Weed of the Week: Japanese knotweed Fallopia japonica | Pitchcare Magazine Weed of the Week: Japanese knotweed Fallopia japonica Weed of the Week: Japanese knotweed (Fallopia japonica) By Laurence Gale What is a weed? By definition a weed is a plant that is growing in the wrong place. Weeds take valuable space, water, sunlight and nutrients that may otherwise be accessible to important crops, in our case turf grasses. Weeds not only compete for these resources they can disfigure and cause problems to playing surfaces. Weeds are very good competitors and take advantage of any opportunities to colonise turf situations, particularly when the sward is under stress and weak, leaving bare soil areas for weeds to populate. Weeds have many mechanisms and characteristics that enable them to do this, having thick waxy cuticle leaves that can be resistant to some chemicals, fast reproduction methods, the ability to reseed in 6 week cycles and deep tap roots enabling the weed to survive in compacted dry ground conditions. Weeds have one of three life cycles: annual; biennial or perennial. Annual weeds: Live for a single season. These weeds germinate from seed in the spring or summer, flower and then die.

Biennial weeds: Live for two seasons. During the first growing season, these weeds remain in a vegetative stage and, in the following year, produce flowers, set seed and die. Perennial weeds: Live for multiple seasons and flower more than once. Perennial structures (rhizomes, stolons, crowns, entire plants or roots) survive from year to year. Some weeds may be harmful to the environment or noxious to your regional ecology. For example Japanese Knotweed (Fallopia Japonica) is fast becoming a major weed problem on road side verges and urban landscape areas, a very difficult weed to eradicate. It is very important to recognise weeds and seek effective controls methods to eradicate them from our facilities. Weeds can also be used as an indicator of soil conditions. For example, knotweed and plantains both indicate soil compaction because they can maintain adequate root respiration at lower oxygen diffusion levels than other plants. Different weeds tolerate different soil conditions, some are alkaline loving and others acid loving. Getting to understand and recognise the physiology of these plants will help you become better turfgrass managers.

This week's weed is: Japanese knotweed Fallopia japonica Fallopia japonica, commonly known as Japanese Knotweed, is also known by the scientific names Polygonum cuspidatum and Reynoutria japonica. This rhizomatous perennial invades habitats primarily through vegetative reproduction, though the plants are known to produce abundant displays of tiny white flowers followed by seed. There are many different approaches to controlling Knotweed, but they all fit into three basic categories; mechanical, chemical and biological - and any permutation of the three. Scientific name perennial Form / Appearance Japanese Knotweed is a prolific weed that grows in dense clumps up to 3m in height, on tubular stems that ascend from the base of the plant. The plant dies back each year, leaving the stems to form a protective framework over the newly forming emerging shoots that begin to grow in the following spring. Roots The roots are woody and have been recorded to depths of 1-5 m or more. The plant forms rhizomes 0.5-5cm in diameter that spread up to 7m laterally each year. The ability of this plant to reproduce itself by rhizomes is the reason this weed so invasive.

Flowers Knotweed forms panicles of white flowers up to 10cm long. The plant flowers from August to October before dying back to leave brittle hollow stems that stand throughout the winter. Leaves Leaves are 6-12 cm x 5-10 cm in size, broadly ovate and truncate at the base. Reproductive method This plant can reproduce itself by seed and by rhizomes. It's vigorous powers of vegetative reproduction mean that it has been able to spread to all parts of the British Isles without the aid of sexual reproduction. Habitat This plant can tolerate most soil conditions, including very acidic soils. The plant is commonly found to populate railway and river embankments. Once introduced will grow in most situations. Establishment and competition with other plant species is aided by a number of characteristics. Firstly, it's ability to grow tall, out smothering many other plant species, it's ability to reproduce by rhizomes and, finally, the amount of debris it leaves behind each year which eventually forms a carpet that shades out other plant flora. This plant is also shade tolerant. Miscellaneous info Knotweed is a native plant of Japan, Taiwan and Northern China.

It was first introduced to Europe and brought to the British Isles in 1825 as an ornamental plant that was collected by gardeners. However, these small collections often changed hands and, over time, the plant began to be spread. Cultural Control Once this weed gets established, it is often difficult to remove or eradicate. However, there are a number of tactics now being used to eradicate or reduce the spread of this weed. In most cases they are labour intensive: Digging out the plant. Often this process must be repeated a number of times to remove all signs of roots and rhizomic growth. All debris harvested must be dealt with as hazardous waste and must be taken to deep land-fill sites suitable for the disposal of live Japanese Knotweed rhizomes. It is an offence to knowingly spread this plant 'in the wild' (Wildlife and Countryside Act 1981). Cutting on a regular basis. Continue to cut down the vegetation back to ground level and keep cutting it until it exhausts itself; not being able to manufacture food from photosynthesis. Covering with plastic or tarpaulins to prevent light getting to the plant, resulting in the plant dying out.

Often difficult to achieve, depending on the location of the plant and possible vandalism problems. A combination of cutting and herbicide is probably the most effective. Chemical control is expensive, not always 100% effective and can have a negative effect on the environment. Due to these problems there is now an increasing interest in the use of biological control, using natural pest and diseases to control the weed. For further information you can link into the Loughborough University web site. Japanese Knotweed | Ontario’s Invading Species Awareness Program Reynoutria japonica var. japonica What Ontario is Doing To prevent the further spread and introduction of this unwanted invader in the province, Ontario has regulated Japanese knotweed as restricted under the Invasive Species Act. For more information on the Invasive Species Act and Regulations visit . Background Japanese knotweed is an aggressive semi-woody perennial plant that is native to eastern Asia. In the 1800’s it was introduced to North America as an ornamental species and also planted for erosion control. It has since spread throughout the United States and Canada. Japanese knotweed is often mistaken for bamboo; however it is easily distinguished by its broad leaves and its ability to survive Ontario winters.

Japanese knotweed is especially persistent due to its vigorous root system, which can spread nearly 10 metres from the parent stem and grow through concrete and asphalt. This invader is very persistent and once it becomes established, is incredibly difficult to control. Range In Canada, Japanese knotweed is established from Ontario to Newfoundland and is also found in British Columbia. In Ontario, it is mostly established in southern and central areas of the province where it mostly grows in gardens, along roadsides and near old buildings or former building sites. Impacts of Japanese Knotweed Spreads quickly, creating dense thickets that degrade wildlife habitats. Reduces plant biodiversity by competing with other native vegetation. Thick layers of decomposing stems and leaves on the ground make it difficult for native plant species to establish. Aggressive plant with a strong root system that has been known to break through asphalt and concrete. Plant populations are extremely persistent. Plants are able to survive severe floods and recolonize areas. It can establish along riverbanks, where pieces of roots can break off and float downstream to start new populations. How to Identify Japanese Knotweed Semi-woody perennial plant capable of reaching 1-3 metres in height.

Stems are round, reddish-purple, smooth and have a bamboo-like appearance. Leaves are ovate with a flat base, reaching 3-6 inches long and 2-5 inches wide with pointed tips. Flowers are greenish-white. Fruit is small and white with wings that help to disperse seeds to new sites. Seeds are brown and shiny. What You Can Do Learn how to identify Japanese knotweed and how to avoid accidentally spreading this invasive plant through its root fragments and seeds. This is especially important if you are planning to do work in an area which contains Japanese knotweed. Learn how to effectively manage Japanese knotweed on your property. The guide to Best Management Practices for Japanese knotweed describes the most effective and environmentally safe control practices for this species. Never buy or plant Japanese knotweed. It is against the law to buy, sell, trade or purposely grow Japanese knotweed. Stay on designated trails and keep pets on a leash. Leaving trails or entering areas containing Japanese knotweed can encourage the spread of this plant.

When leaving an area containing Japanese knotweed, inspect, clean and remove mud, seeds and plant parts from clothing, pets (and horses), vehicles (including bicycles and ATVs), and equipment such as mowers and tools. Do not compost Japanese knotweed in your backyard composter. Both seeds and rhizomes (horizontal plant stems growing underground) could survive and grow in compost, unless high enough temperatures are reached to kill the reproducing structures. Contact your local municipality to determine if plant material can be brought to their composting facility. Ontario composting facilities monitor the compost process and meet provincially regulated temperature requirements. If you have any information about the illegal importing, distribution or sale of Japanese knotweed, report it immediately to the MNRF TIPS line at 1-877-TIPS-MNR (847-7667) toll-free anytime. You can also call Crime Stoppers anonymously at 1-800-222-TIPS (8477).

If you’ve seen Japanese knotweed or other invasive species in the wild, please contact the toll free Invading Species Hotline at 1-800-563-7711, or visit EDDMapS Ontario website to report a sighting. Other Resources Fallopia japonica - NorthWoods Fallopia japonica Fallopia japonica - Japanese Knotweed (Polygonaceae) Also refered to as Polygonum cuspidatum Japanese knotweed Description: Japanese knotweed is a member of the polygonaceae or knotweed family (Weston, 2005). It is a shrub like dioecious herbaceous perennial plant (Seiger, 1997). This species is native to Southeast Asia and was introduced to the United States in the 1870s as an ornamental plant. This species is now classified as highly invasive, exotic, and a noxious weed within the United States, UK, and Canada (Weston, 2005). Japanese Knotwood forms upright with reddish purple bamboo-like stems. These stems turn green with purple speckles once they produce leaves. These hollow stems can grow to a height of 5 meters.

Leaves are usually triangular or heart shaped with a pointed end. The leaves are approximately 15cm long by 8-10cm wide. This plant produces small, white flowers between July and August producing as many as 191,892 seeds per stem. Seeds are about 2.5mm long, triangular, and shiny. Habitat and Range : Japanese knotweed is usually found along riparian zones, where it can receive large amounts of sun and water. This plant is most commonly found beside bodies of water, but because if its invasive nature it is found in many disturbed areas, such as roadsides (Weston, 2005). This plant can also tolerate less than suitable environmental conditions. It can survive in areas of high shade, high temperatures, high salinity, and even areas where there is drought. Along with these conditions, this species has the ability to also live in a variety of soil types and pH levels, silt, loam, sand, and varying levels between a pH of 4.5 to 7.4 (NBII, 2005). This invasive plant species thrives mostly in the Northeast, ranging from Georgia all the way to Maine.

But has successfully dispersed itself across the central US and within the Pacific Northwest. As of 2003, Japanese knotweed had been found in forty of the fifty states (Weston, 2005). Resource Acquisition : Japanese knotweed is a photosynthetic plant that prospers in open area habitats with both full sun and water rich soil. As described before, it can survive in both nutrient poor and sunlight poor areas, but will subsequently grow slower (NBII, 2005). This plant can survive in these areas because of the energy reserves it has within its rhizomes in the root system (Forman, 2003). These rhizomes can grow more than 1 meter in depth and 15-20 meters in length and are usually fleshy to woody texture with a distinct orange interior (NBII, 2005). Reproduction : The key means of reproduction by Japanese knotweed is through vegetative reproduction. This is done by means of rhizomes found in the plants’ roots and the spreading of stem fragments. Rhizomes grow horizontally underground and give way to replications and new stems.

Stem fragments are commonly spread by the movement of water and by interactions of humans. When debris from the plant enters the water source it can travel to a new bank where it can then grow. When soil is transported from an area housing Japanese knotweed it can carry parts of the plant within the soil which can later develop where ever the soil used (Weston, 2005). Plants can grow from as little as 1g of root material and can successfully grow from as deep as 1 meter in the ground (NBII, 2005). Another method of reproduction, that has just recently been proven true, is through seeds. This plant does produce germinating seeds but it is not the main source of reproduction. Most often, seedlings will not survive if they try to germinate under well established knotweed stands. This is because sunlight can not penetrate the dense canopy of the mature plants above the seedling. Seeds can be successful if they can be dispersed into an open area. It is much easier for Japanese knotweed to grow horizontally from its rhizomes underground, but can reproduce through seeds (Forman, 2003).

Dispersal : In reference to the reproduction practices of Japanese knotweed there are many forms of dispersal. As mentioned before, movement by water currents and transportation of habitat material are the most common forms of plant dispersal. Waste from cutting plants and doing garden management can give rise to new plants where ever the waste is dumped. Seeds are dispersed through wind(NBII, 2003). Defenses and Natural Enemies : One defense mechanism that this plant has is a compound, polygonum, found in its root systems. This compound is thought to have a potential allelopathic property, which could be a reason for its successful invasive behaviors (Weston, 2005). Japanese knotweed has no dominating enemies. Grazing animals can eat this plant but usually it is only eaten when first placed in the animals’ environment specifically for forage. Research looking for possible biological controllers of the plant has begun; candidates include a specific beetle, a possible pathogen, a specific fungal species, and even herbivorous insects (Weston, 2005). Environmental Damage: Japanese knotweed is considered a top invader and this is because of its capabilities of taking over a habitat and subsequently pushing native flora out.

This plant is extremely persistent in limiting the amount of light that reaches the soil and surrounding vegetation. This very dense plant kills off species by reducing their light source. Along with decreasing the amount of sunlight reaching other plants it has very slow decomposing leaf litter. This can consequently change the surrounding plant growth and diversity but continue to keep a strong habitat for Japanese knotweed. The changes in habitat and a species diversity from japanese knotweed affects both plants and animals in the environment. This is because the plant forces both to leave the area. This plant can also change the available water supply, carrying capacity, and increase erosion along the banks of rivers and streams (Weston, 2005). It is very difficult to erradicate Japanese knotweed. The top photo shows a plot of land directly after mowing, the bottom photo shows the same plot two months later. Management: The management and eradication of Japanese knotweed is extremely difficult, if not impossible. There are three management styles, cutting, uprooting, and herbicides. Cutting is the most frequently used method where the above ground biomass is cut during the growth season.

It is impossible to eliminate the plant by just cutting, but cutting can control the species and therefore allow for other possible forms of management. Plants should be cut every four weeks throughout the growing season and also before August when the plants flower and seeds are dispersed. It has been proven that by using the cutting technique underground rhizome biomass is also reduced. More than one year of cutting may be necessary in order to establish control over the plant. Once there is control, cutting needs to continue to be persistent. Even though cutting does have positive outcomes in decreasing the growth of this invasive species it might also cause damage and disturbance due to the continuous trampling (Seiger, 1997). Herbicides and uprooting are the two other methods but neither are as effective as cutting. Herbicides can be effective when trying to decrease the spread and growth of Japanese knotweed, but are more damaging in the long run. They are usually expensive, they are not healthy or suggested for use in riparian zones, they impact non-targeted plant species, and the herbicides can stay in the soil long after use as ceased. Uprooting requires much more work than cutting and has detrimental effects to the habitat.

All stem and rhizome fragments must be collected in order to prevent re-growth of the area, the waste from the process must be disposed of in an appropriate manner (burning), and the habitat will be severely damaged as the soil and area of the plant will be completely dug up (Seiger, 1997). Reference individual in the Northwoods: A stand of knotweed can be found in the Northeastern corner of the Northwoods apartments, at the intersection of the woods and apartment space near the powerline. Related species (congeners) in Northwoods: Japanese knotweed has five close relatives of itself. - Fallopia sachalinensis, syn. Polygonum sachalinense = Giant knotweed - Fallopia baldschuanica, syn. Polygonum aubertii, Polygonum baldschuanicum = Silver lace vine - Fallopia japonica var.

compacta = The dwarf form of Fallopia japonica - Fallopia x bohemica = the hybrid between Fallopia japonica and Fallopia sachalinensis - Polygonum wallichii = Himalayan knotweed (Alberternst, 2006) None of these species exist in the Northwoods, but there is a species that has a similar characteristic of Japanese knotweed that can be found in Northwoods. This is the bracken fern, also known as Pteridium aquilirum. The similar feature between these two species is that they both are difficult to get rid of. Cutting alone will not eliminate either of these plants, because the plant can regenerate itself once cutting stops (Seiger, 1997). Even though there are no relatives of Japanese knotweed in the Northwoods there are similar plants and also other invasive species, such as Euonymus alatus (Burning bush). NOTE: consider searching the site for certain terms/species that a reader may not understand or recognize, and create internal links to those objects. References: Alberternst, B. & Bohmer, H.J.

NOBANIS – Invasive Alien Species Fact Sheet – Fallopia japonica. Online Database of the North European and Baltic Network on Invasive Alien Species. (2006): Forman, Jennifer, and Richard V. Kesseli. "Sexual Reproduction in the Invasive Species Fallopia Japonica." American Journal of Botany 90 (2003): 586-592. National Biological Information Infrastructure, and Invasive Species Specialist Group. "Fallopia Japonica." Global Invasive Species Database. 28 Nov. 2005. < >. Seiger, Leslie A., and Henry C. Merchant. "Mechanical Control of Japanese Knotweed." Natural Areas Journal 14 (1997): 341-345. Weston, Leslie A., Jacob N. Barney, and Antonio Ditommaso. "A Review of the Biology and Ecology of Three Invasive Perennials in New York State: Japanese Knotweed, Mugwort, and Pale Swallow-Wort." Plant and Soil 277 (2005): 54-58. Fallopia japonica var.

japonica (Japanese Knotweed): Minnesota Wildflowers Fallopia japonica var. japonica (Japanese Knotweed) Plant Info part shade, sun; moist, disturbed soil, fields, along roads and railroads, gardens Bloom season: Pick an image for a larger view. See the glossary for icon descriptions. Detailed Information Flower: Flowers are in branching spike-like clusters in the upper leaf axils. Individual flowers are 1/8 inch across, white to greenish or pinkish, with 5 petals and 8 stamens. Male and female flowers are separate (dioecious). Leaves: Leaves are simple, toothless, hairless, alternate, broadly oval to egg-shaped with a pointed tip, 3 to 6 inches long, 2 to 4½ inches wide, on a long stalk. A semi-woody perennial, it is fast growing and has hollow, bamboo-like stems that form dense, leafy thickets becoming woody with age. Shoots arise from coarse, spreading rhizomes that can attain lengths up to 50 feet. Fruit: Female flowers can produce small 3-angled black-brown fruit but seed production is rare, primarily spreading by rhizomes.

Notes: Japanese Knotweed goes by both latin names Polygonum cuspidatum (more common in North America) and Fallopia japonica (more common in Europe), with the latter accepted by “Flora of North America” (FNA, our definitive reference). Native to Japan, Japanese Knotweed was introduced to the UK in 1825 by gardeners as an ornamental. In the late 1800's it was brought to North America and quickly escaped cultivation. It is widespread in the eastern US and is likely now present in all of the lower 48 states. It is scattered across Minnesota and is winter hardy. While a major ecological threat to Minnesota's riparian areas, it is still carelessly moved from place to place by gardeners and is even still available in the garden trade. It is possibly in a garden center near you. FNA notes 4 varieties of F. japonica but there are also cultivars in the garden trade. The species described on this page is var. japonica. Dwarf Japanese Knotweed, var. compacta, is smaller with pink flowers and is less common but has also been widely planted in Minnesota.

A hybrid between Japanese and Giant Knotweeds—Bohemian Knotweed (Fallopia × bohemica)—is also present in the state. If you have Japanese Knotweed on your property: We discourage the movement and use of this plant for landscape purposes as it can quickly get out-of-control. We recommend control and removal wherever this plant is found. Control of this plant is extremely difficult once it becomes established. Digging of even small clumps is labor intensive and safe disposal of the rhizomes is problematic. Intensive mowing of tops or mowing in combination with herbicide applications (such as Arsenal®) can deplete this plant's energy reserves over time. There are no biological controls for Japanese Knotweed at this time. Japanese knotweed - Invasive Species IrelandInvasive Species Ireland ISI Forum Japanese knotweed Please note, the Invasive Species Ireland Japanese Knotweed Best Practice Management document has been withdrawn until further notice (1st November 2016) Japanese Knotweed stems Japanese knotweed (Fallopia japonica), is an invasive herbaceous perennial (a plant that can live more than one year).

Since it was introduced as an ornamental plant in the 19th Century from Japan, it has spread across the island of Ireland, particularly along watercourses, transport routes and waste grounds where its movement is unrestricted. Japanese knotweed can: Seriously damage houses, buildings, hard surfaces and infrastructure growing through concrete, tarmac and other hard surfaces, usually where weaknesses already exist. Threaten native plants and animals by forming dense thickets and releasing a chemical subsatnce to inhibit other plants growth. Block routes used by wildlife to disperse. Riverside Japanese knotweed damages flood defence structures and reduces the capacity of channels to carry flood water. Identification National Biodiversity Data Centre’s ID sheets Red/purple shoots appear early in spring which in some case resemble an asparagus like appearance but, as the canes grow, the leaves unfurl and the plant takes its more characteristic appearance. The mature canes are like bamboo, being hollow, and have a characteristic pattern of purple speckles. The plant can grow to over 3m in height. Flowering occurs in late summer/autumn and consists of small creamy white flowers. During the winter the leaves die back and reveal orange/brown woody erect stems.

The underground rhizomes which can extend up to 7 meters from the parent plant and up to 3 meters in depth (sometimes further in exceptional cases) are thick and woody with a knotty appearance and when broken reveal a bright orange-coloured centre. Only female Japanese knotweed plants have been recorded to date in Ireland, Northern Ireland and GB, hence it is spread entirely from site to site through the deliberate or accidental movement of rhizome fragments or cut stems. Some reports suggest a fragment of knotweed as little as 0.6 grams can result in new growth. The key features of the plant are summarised below; Produces fleshy red tinged asparagus like shoots when it first breaks through the ground in an established stand. Himalayan Knotweed – image courtesy of Jenny Seawright Has large, heart or spade-shaped green leaves which are approximately the size of your hand. Has leaves arranged in a zig-zag pattern along the stem. Grows up to 3 metres in height. Yellow / cream flowers in late summer Hollow bamboo like stems which have distinctive ring like nodules at regular intervals along it. Brown stem in winter once it has died back.

Extensive rhizome system (roots) (7m x 3m approximately) Orange centred rhizome. Spread entirely via the movement of plant and rhizome fragments. Similar species The following species are commonly confused with Japanese knotweed: dock; buddleja (butterfly bush); knotgrass, Russian Bohemian Knotweed vine (also known as mile a minute weed), red osier dogweed, some species of viburnum and redshank (herb). Be aware that in Northern Ireland, Ireland and other parts of the UK other knotweed species occur. Namely giant knotweed , hybrid knotweed , IFI_Bohemian_knotweed_Dec-2011-version-1 and Himalayan knotweed which are all listed under legislation. Both the giant and hybrid knotweed can easily be confused with Japanese knotweed and can be distinguished by their leaf size and shape (see below from the GB NNSS ID sheet for drawings on page 2). Impacts and key issues Japanese knotweed grows vigorously and outcompetes native plants. Japanese knotweed forms tall thickets that exclude all other vegetation, shading the area below. Native plants can rarely compete with this invasive species and local plant biodiversity is reduced.

Rivers, hedgerows, roadsides and railways can form important wildlife corridors for native plants and animals to migrate and disperse along, and large infestations of Japanese knotweed can block these routes for wildlife. Japanese knotweed can also seriously damage buildings, hard surfaces and infrastructure in some cases. Once established underneath or around the built environment, it can be particularly hard to control, in some cases growing through concrete and tarmac and other areas of hard-standing. When Japanese knotweed colonises riverbanks, it can damage flood defence structures and reduce the capacity of channels to carry flood water. The following provides a summary of the key impacts of the species: Excludes native species; Dies back in winter leaving river banks vulnerable to erosion; Subsequent potential sedimentation impact on fish spawning areas; In some cases where existing weaknesses occur, it can damage building foundations; Collects litter in urban areas; and Can damage hard surfaces where cracks or weaknesses occur, by forcing its way through. How is the species spread Even though Japanese knotweed plants flower the principal means of spread is entirely through the deliberate or accidental movement of rhizome fragments or cut stems.

Japanese knotweed has an extraordinary ability to spread vegetatively from crown, stem and rhizome (underground root) if disturbed. Even tiny amounts of cut stem, crown or rhizome are capable of producing a new plant. Controlling spread is therefore dependent on preventing the spread of the stem, crown or rhizome. Management summary N.B. It is the responsibility of the operator to ensure that all appropriate legislation is followed when using herbicides and that their training is commensurate with their duties. Chemical control In GB and Northern Ireland the only chemicals which can now be used to eradicate Japanese knotweed are those containing Glyphosate as the herbicide active ingredient. Glyphosate is known to be residual in the environment for 24 – 48 hours after spraying/application. The optimum time of application is late season or before the foliage starts to die back. TO PROTECT POLLINATORS, TRY NOT TO SPRAY PLANTS WITH HERBICIDE WHILE THEY ARE STILL IN FLOWER!! However, the goal to achieve Japanese Knotweed removal along with the restoration of those habitats to native species is a much more sustainable long term solution. Sometimes non -target species will be unavoidably effected but these impacts should be reduced where possible.

An early season spray maybe required in year 1 to assist with access for the late season spray. Glyphosate will also kill grasses – only approved for use near water in certain products, always check first. Please note; As from 26th November 2015 anyone who purchases herbicides/pesticides authorised for professional use must ensure that the intended end user holds the relevant specified certificate(s). (Section 9 (5), The Plant Protection Products (Sustainable Use) Regulations 2012) & (Part III of the Food and Environment Protection Act 1985, and related Codes of Practice). Deep excavation and deep burial This is an option that is used in situations where there is a pressing development need for the site and time which would not allow for insitu herbicide control over a longer period of time. If you require more information on this method, it is recommended in these instances to seek advice from a suitably experienced knotweed specialist. The Environment Agency Knotweed COP guidance has also been withdrawn by the GB Environment Agency. Non-chemical control Biological: This method is not usually recommended for control of this species.

Grazing is not an eradication tool but is helpful in suppressing the plant and reducing spread in certain circumstances. You must remember that Japanese knotweed has an extensive rhizome system that will not be grazed. The psyllid bug Aphalara itadori was released in England in 2010. The effectiveness of this species at reducing the vigour of Japanese knotweed is still being assessed. There are no current plans to release this species in Ireland or Northern Ireland until more information is available. It is illegal to release any non-native animal into the wild in both Ireland and Northern Ireland without a licence. CABI weed biocontrol summaries May 2015 In general Herbicides can be applied using a range of suitable applicators such as a knapsack sprayer. Control is easier if dead winter stems are tidied over the winter months to assist with access before growth commences i.e. to prevent tripping on them or them interfering with your knapsack lance. It is advised to leave the canes in situ on a barrier membrane if possibe, to reduce the risk of spread to other sites. Be careful to avoid spreading knotweed crowns when tidying dead canes.

Application in sensitive vegetation areas is best achieved by stem injection or weed wiper. Further details on control measure Remember that it is illegal to dump Japanese knotweed waste in the countryside. It is illegal to plant or otherwise cause Japanese knotweed to grow. In Northern Ireland it is illegal to dispose of Japanese knotweed, or knotweed contaminated soil, at a landfill site without informing the landfill site that the waste material is Japanese knotweed. In Northern Ireland Waste Transfer Notes are required by the licensed haulier to transport the material to the landfill site. To move soil in the Republic of Ireland that contains Japanese knotweed will require a license from NPWS. Japanese knotweed can regenerate from very small fragments of rhizome (as little as 0.7 grams). Plant material should not be composted as it is ineffective and may result in further spread. Plants should be treated in the same season as they are identified. Try not to let stands of Japanese knotweed become established as this species is very difficult to control. If it is a recent introduction it is best to tackle it quickly to prevent the rhizome system from fully establishing. Japanese knotweed is not an easy plant to control due to its extensive underground rhizome system.

Therefore treatment often needs to be repeated until no regrowth is observed over several years for eradication to be achieved. Repeated herbicide treatments over several years are normally recommended for complete control of Japanese knotweed. Continued monitoring of the treated areas should also be carried out to ensure that no new shoots appear. If you intend to deep bury the dead Japanese knotweed material or dispose of it off-site for deep burial, it is recommended that you should only use glyphosate formulations. Other persistent herbicides may not be allowed for deep burial under various waste regulations and due to a potential risk of pollution of groundwater. It is recommended not to deep bury or bund Japanese knotweed onsite within 10 metres of the site boundary as a precaution. When planning works with Japanese knotweed ensure you have built in biosecurity measures into your management plan. For example fencing off and creating a buffer around the area if it is a development site, warning signs, use of set haulage routes, covering loads, ensuring all staff working on the site are aware of the presence of knotweed, use of a set cleaning area etc.

Sources of further information: Please note, the Invasive Species Ireland Japanese Knotweed Best Practice Management document has been withdrawn until further notice (1st November 2016) How to Kill Japanese Knotweed - Killing | Treatment | Control How to kill Japanese Knotweed. Fallopia japonica japonica control and treatment Japanese Knotweed. Fallopia japonica var. japonica - Killing this invasive weed Japanese Knotweed has been around for years. Many many years, for as a young boy, I used to use the hollow stalks for peashooters. My friends also used to 'smoke' the dead stalks in the winter, but that is another story! Nowadays - some 55 years on - it has become public enemy number one insofar as weeds are concerned - it is not easy to kill or control! No longer a toy, but now a serious menace - so much so that there are strict rules (laws) governing what you can and cannot do if you have the wretched weed! Japanese Knotweed treatment is essential as it can cost building contractors and developers dearly - sometimes many thousands of pounds if they have it on their building site. Control of Japanese Knotweed is essential.

Furthermore, if soil removed from a building site is proven to have any trace of Japanese Knotweed, then there are hefty fines that can be imposed, together with which there can by claims for compensation if the recipient's land becomes contaminated with Japanese Knotweed. You need to know how to kill and then control Japanese Knotweed Killing Japanese Knotweed It is an invasive weed - spreading relentlessly through the UK after being introduced by some unsuspecting plant hunter as a highly desirable exotic garden plant in the middle of the nineteenth century. It does not spread by seed, for it is infertile. So all of the weed crops are seen throughout the UK were spread vegetively. They started their new life as a little bit of plant - maybe just a centimetre long that was transported to the new home! This can happen by way of topsoil import, being carried by birds or animals, or even by some unsuspecting and untidy human. Certainly the transportation of building site excavation material and debris has been a contributory factor in the spread of Japanese Knotweed - as has the moving of general garden waste and rubbish from an infected area to a landfill site and thereafter to anywhere!

Waterways, railway embankments, roadside verges, building sites, and of course, gardens, are all potential home to the Japanese Knotweed (- Fallopia japonica var. japonica). In the native habitat, Japanese Knotweed has several 'predators' ranging from certain insects and a few diseases. These keep the 'problem' confined. In the UK, no such predators exist - though experiments suggest that a small insect can now be released, which will feed on the invasive weed, and hopefully control its spread if not in time totally eradicate it. Hopefully this insect will not then turn its attention to our ornamental varieties of Knotweeds - Persicarias and Polygonum! As a garden weed, it can cause many problems in borders, or invade lawns - where the small fragments cut up by a lawn mower can then spread to other parts of the garden. These lawn mowing can also then be transported to other areas by way of household waste, or by fly-tipping garden maintenance operatives. Not all garden maintenance firms are fly-tippers of course! Structural Damage caused by Japanese Knotweed As well as being a 'weed' Japanese Knotweed is a serious problem in terms of structural damage.

Once it has taken hold in ground near to buildings, it can soon cause problems of damage to buildings and certainly paved areas such as footpaths and patios. The underground stems (Rhizomes) are capable of diving down into the soil to a depth of 3 metres. Japanese Knotweed has even been found to be growing through the floorboards of a living room, after presumable growing under the foundations of the house! So - NOT to be ignored. One it takes hold, it is capable of spreading over an area of a few hundred metres within the space of a year! Control and Treatment If you find Japanese Knotweed (Fallopia japonica var japonica) on your land, it is your responsibility to eradicate it - kill it - control it, and prevent its further spread. It is no use just phoning the local council. It is your problem. You are responsible for your own Japanese Knotweed Control. If of course, it has been bought on to your land with a load of topsoil, or other similar provable source, then you have a claim against the persons who imported it onto your land.

If you are in a new build property, and suffer from the weed, then it may well be that there is a case against your builder! Don't try composting it, this will not kill or control it - it is a waste of time and will lead to problems if you then use that compost on your garden! Weedkillers and how to Kill Japanese Knotweed No weedkillers which are persistent in the ground should be used for controlling, treatment or killing Japanese Knotweed (Fallopia japonica var japonica). The two Japanese Knotweed Treatments which seem to offer the best solution in the UK are those with Glyphosate as main treatment ingredient, or weedkillers containing 2,4-D. Glyphosate is normally sold under the brand name of Roundup, Tumbleweed or Elimin8. There are others! If you mean business with getting rid of Japanese Knotweed, then you should invest in a good sprayer and use the concentrate form of the weedkillers, rather than the silly little Ready to Use spray cartons. Glyphosate and 2,4-D can be used as a Japanese Knotweed Treatment foliar spray - READ THE DIRECTIONS!.

It will need to be applied over 2-3 years to totally kill off the Knotweed. This is a long term war, and for success you will need to win several battles! A further method that can be adopted - though rather time consuming - is that of 'injecting' the stems with a strong solution made from the concentrate. In this case, it will need to be around plus ten times the recommended dilution used for spraying. It has been said that the best time for 'injection, is during the Autumn months. We disagree with this, and have seen this carried out very successfully in the full growing season. The mixture can be directed directly into the hollows stems, but far better to cut the cane stems to around 8-10in from the ground - just below a visible joint. This will give you a hollow receptacle into which you can pour approximately your mixture - about 2-3 cm deep. Any further re-growth - and there will be some, can then be foliar sprayed in the normal manner. Remember, both Glyphosate and 2,3-D are weedkillers that will also kill off any of your prized plants if you accidentally spray them. The same is true of your lawn!

Alternatively, you can enlist the help of a professional weed clearance company. Recommendations for for control of Japanese Knotweed for contractors and building development The costs - direct and indirect - can be quite considerable if found on building land. Directly, you can negotiate a better price or price adjustment to take into account the expense of dealing with Japanese Knotweed. You cannot simply ignore it, as a buyer or a seller. By law, Japanese Knotweed has to be dealt with. Early identification of Japanese Knotweed is essential in obtaining land for development purposes, or land that has laid vacant and is now being considered for development. Soil which has been contaminated with Japanese Knotweed will need to be treated before it can be re used on the site for landscape or other purposes. The alternative being that untreated soil will need to go to landfill - at cost. It is essential that your staff can identify Japanese Knotweed or a consultant employed to advise. Likewise, no topsoil should be allowed on to your site until there has been an inspection of the load, and it is assessed as being free form the weed. A suitable member of staff should be delegated to ensure that all of this is in place.

It is an offence under the Wildlife and Countryside act 1981 to allow Japanese Knotweed to be spread into the wild. Together with this, all waste containing Japanese Knotweed is subject to control under the Environmental Protection Act 1990. Developers and contractors may get advice on the Environmental hotline - 08708 506 506. Copyright ï¿½ Gardenseeker.com - 2000 - 2017 Weed of the Week: Yarrow (Achilles millefolium) | Pitchcare Magazine Weed of the Week: Yarrow (Achilles millefolium) Weed of the Week: yarrow (Achilles millefolium) By Laurence Gale What is a weed? By definition a weed is a plant that is growing in the wrong place. Weeds take valuable space, water, sunlight and nutrients that may otherwise be accessible to important crops, in our case turf grasses. Weeds not only compete for these resources they can disfigure and cause problems to playing surfaces.

Weeds are very good competitors and take advantage of any opportunities to colonise turf situations, particularly when the sward is under stress and weak, leaving bare soil areas for weeds to populate. Weeds have many mechanisms and characteristics that enable them to do this, having thick waxy cuticle leaves that can be resistant to some chemicals, fast reproduction methods, the ability to reseed in 6 week cycles and deep tap roots enabling the weed to survive in compacted dry ground conditions. Weeds have one of three life cycles: annual; biennial or perennial. Annual weeds: Live for a single season. These weeds germinate from seed in the spring or summer, flower and then die. Biennial weeds: Live for two seasons. During the first growing season, these weeds remain in a vegetative stage and, in the following year, produce flowers, set seed and die. Perennial weeds: Live for multiple seasons and flower more than once. Perennial structures (rhizomes, stolons, crowns, entire plants or roots) survive from year to year. Some weeds may be harmful to the environment or noxious to your regional ecology.

For example Japanese Knotweed (Fallopia Japonica) is fast becoming a major weed problem on road side verges and urban landscape areas, a very difficult weed to eradicate. It is very important to recognise weeds and seek effective controls methods to eradicate them from our facilities. Weeds can also be used as an indicator of soil conditions. For example, knotweed and plantains both indicate soil compaction because they can maintain adequate root respiration at lower oxygen diffusion levels than other plants. Different weeds tolerate different soil conditions, some are alkaline loving and others acid loving. Getting to understand and recognise the physiology of these plants will help you become better turfgrass managers. This weeks weed is: Achilles millefolium (common yarrow) Scientific name Perennial Form / Appearance The leaves are lanceolate and divided into narrow segments, appearing fern-like. The leaves of yarrow are strongly scented. Yarrow flowers are rarely seen in mowed situations. Roots Yarrow has a very fibrous root system that consists of many rhizomes which play a major role in the plant's ability to establish itself in turf and make the plant difficult to eradicate. Flowers White or yellow flowers are formed at the ends of stems in dense, flat clusters.

Flowering occurs in June to October. Leaves Leaves on mature plants are finely dissected, giving them a feathery appearance, and resemble a fern. Reproductive method Yarrow reproduces itself from seed and Rhizome development. Habitat Yarrow is a drought tolerant perennial that can endure dry, impoverished / infertile sandy soils and survive with little or no maintenance. Yarrow's main growth period is from April through to September. Yarrow is a good indicator of infertile soil conditions. Miscellaneous info Yarrow is also known as milfoil, thousand leaf or woundwort. Yarrow is used as medicinal remedies by herbalists, it has been valued since ancient times for its ability to stop bleeding, hence its nickname "nosebleed." Today, yarrow is valued for its ability to fight off colds and flu. Yarrow is a tough, durable and aromatic weed. Cultural Control Yarrow can be mechanically or physically removed. Care should be taken to assure that all roots are thoroughly removed. Close mowing prevents seed head formation, whilst maintaining a dense sward will deter or prevent yarrow from establishing. Good soil fertility is essential, maintaining a soil pH of 6.5 to 7.

Chemical Control Apply selective broadleaf herbicides when plant growth is active. There are a number of products available for controlling broad leaf weeds in established turf. These chemicals are best used when the weeds are actively growing, usually between April-October. Tritox (Contains 178g/L (16.2%w/w) MCPA 54.g/L(4.9%w/w) mecoprop-p and 15g/L (1.4%w/w) dicamba and potassium salts. Scotts. Intrepid 2. (Contains 20.8g/L dicamba,166g/L dichlorprop-p ans 166.5g/L MCPA). Scotts. Greenor. (Contains: 40g/L fluroxypyr, 20g/L clopyralid and 200g/L MCPA). Rigby Taylor. Bastion T. (Contains: 72g/L fluroxypyr and 300g/L mecoprop-p ). Rigby Taylor.

Dormone (Contains 465g/L2,4-D(38.1%w/w) as the diethanolamine salt). A herbicide which can be used near water. Bayer Environmental Science. Supertox 30 (Contains 95g/L (8.8%w/w) mecoprop-p and 93.5g/L(8.7%w/w) as the diethanolamine salts). Bayer Environmental Science. These herbicides are usually applied as a liquid using watering cans, knapsack sprayers and vehicle mounted sprayers. Ensure you follow manufacturer's directions, health & safety and product data sheets, and comply with COSHH regulations, when using these chemicals. Herbicides are an effective tool where high quality turf is desired. However, they must be applied with care and accuracy and in the context of a good overall turf management program. Before using any herbicide, carefully review the label for conditions of use including rates, methods of application, and precautions. Never use an herbicide in any manner contrary to its label and be sure that the herbicide will not injure the turfgrass species Like this article?

Japanese Knotweed Control | LoveTheGarden.com Japanese Knotweed Control Japanese Knotweed Control By Geoff Hodge, Botanical Expert (BSc, MCIHort) Japanese knotweed (Fallopia japonica) is a garden weed that is a real thug. It needs to be controlled before it spreads and becomes a severe problem. Its root system is so strong that it can cause severe damage to paths, drives and even house foundations. What is Japanese Knotweed? Japanese knotweed is a perennial plant – living for many years – that spreads rapidly through the ground thanks to its deep penetrating rhizomes (creeping underground stems). These are strong enough to push up through concrete, Tarmacadam and similar surfaces and can even damage buildings. Each spring it produces bamboo-like stems, growing to more than 2.4m (8ft) high that will suppress other plants below. In winter, the stems die back to ground level. Its presence in gardens is such a problem that many property lenders are refusing to offer mortgages for properties affected by it, and in some cases property values have fallen by many thousands of pounds where it exists. Interestingly, Japanese knotweed was introduced into Britain in the 19th century as an ornamental plant!

The leaves, stems and creamy-white flowers produced in late summer and early autumn were considered very attractive. It does not produce seeds, but spreads and is propagated from even very small pieces of its rhizome. Japanese Knotweed removal and control is not an easy or quick task, but one that may save you a lot of money in the long run. Japanese Knotweed Identification Japanese Knotweed is quite easy to indentify due to the disctintive heart shaped leaves and hollow green canes with purple speckles. The canes will start to appear in early spring and be mature by early summer. Spikes of white flowers will appear in late summer, but as the seeds are very rarely fertile they have little benefit to the spread of this weed. Japanese Knotweed will tend to grow in dense clumps, the canes will turn brown in the autumn but can remain standing throughout the winter with fresh shoot growing up around them the following spring. How to Get Rid of Japanese Knotweed Early action on Japanese Knotweed control is essential to prevent it spreading. You can start by digging up plants, but the rhizomes are very tough and deep and you may have to attack them with a pickaxe or similar.

No matter how careful you are, pieces of root are bound to remain and regrowth will occur. Then repeatedly destroy any regrowth to exhaust the strength and energy remaining in the rhizomes. This could take several years to give full control. Legislation on Japanese Knotweed In accordance with The Anti-social Behaviour, Crime and Policing Act 2014 individuals and companies must take action to remove and prevent the spread of invasive non-native plants such as Japanese Knotweed. Digging out the rhizomes does create a problem over disposal, since Japanese knotweed is classed as 'controlled waste' under the Environmental Protection Act 1990. Under the provisions of the Wildlife and Countryside Act 1981, it is an offence to cause Japanese knotweed to grow in the wild, so it is illegal to simply dump it anywhere. Much of its spread is through topsoil movement, for instance. Once dug up, it can be destroyed by allowing the plants to thoroughly dry out and then burning it. Japanese knotweed/RHS Gardening Other related species What is Japanese knotweed? Japanese knotweed is a strong-growing, clump-forming perennial, with tall, dense annual stems.

Stem growth is renewed each year from the stout, deeply-penetrating rhizomes (creeping underground stems). New legislation An amendment to the Anti-social Behaviour, Crime and Policing Act 2014 includes Japanese knotweed and other invasive non-native plants. Full details of how this will work for the homeowner are not yet available, but here are some key points: It is not illegal to have Japanese knotweed in your garden On your property, you should aim to control this plant and other invasive non-native plants such as Himalayan balsam and giant hogweed , to prevent them becoming a problem in your neighbourhood. If they have a "detrimental effect of a persistant or continuing nature on the quality of life of those in the locality", the legislation could be used to enforce its control Control can be carried out by the homeowner (see the control section below) and doesn't require a specialist company. However, a specialist company will be skilled at control and can dispose of the plant waste For more information, see the Home Office Information Note: Japanese knotweed . Appearance In spring and summer, bamboo-like shoots grow to 2.1m (7ft) tall.

Leaves are up to 14cm (5½in) in length and the creamy-white flower tassels produced in late summer and early autumn reach up to 15cm (6in). The stems die back to ground level in winter. ‹ › Japanese knotweed is a perennial weed, producing tall canes, up to 2.1m (7ft) in height during the summer. The canes have characteristic purple flecks, and produce branches from nodes along its length. These branches support shovel-shaped leaves.Bare stems typical of Japanese knotweed's appearance in winter The problem Japanese knotweed was introduced from Japan in 1825 as an ornamental plant. The plant is not unattractive but its rapid annual growth and relentless spread, allows it to easily overwhelm other garden plants. Where established as a wayside weed, native plants are also aggressively over-run. Although it does not produce seeds, it can sprout from very small sections of rhizomes and, under the provisions made within the Wildlife and Countryside Act 1981, it is an offence to cause Japanese knotweed to grow in the wild. Much of its spread is probably via topsoil movement or construction traffic.

Control Non-chemical controls When tackling Japanese knotweed, cultural control methods pose some problems; Digging out is possible, but due to the depth that the rhizomes can penetrate, regrowth usually occurs. This method also creates problems over disposal as Japanese knotweed is classed as 'controlled waste' under the Environmental Protection Act 1990. This requires disposal at licensed landfill sites. Specialist Japanese knotweed contractors are usually licensed to safely remove the weed from site but check first before employing their services. Alternatively, it can be destroyed on site by allowing it to dry out before burning. On no account should Japanese knotweed be included with normal household waste or put out in green waste collection schemes If digging out is attempted, remove as much root as possible, then repeatedly destroy regrowth. In this way the energy reserves in the remaining underground parts will be gradually exhausted; a process which may, however, take several seasons Biological control A plant sucker (psyllid) is being released in the UK as a biological control for Japanese knotweed. It is currently only being released at a handful of trial sites and is not available to gardeners.

However, if successful it will be released more widely and will become widespread in Britain over the next five to ten years by natural spread Chemical controls When using weedkillers, always follow the instructions on the pack to make effective and economic use of the product while minimising risks to people and the environment. Glyphosate Perhaps the most effective and simplest method for the home gardener to tackle Japanese knotweed is with the glyphosate-based weedkiller Scotts Roundup Tree Stump & Rootkiller. This has label recommendation for controlling Japanese knotweed, instructing it to be applied to the cut canes. Bayer Garden Super Strength Weedkiller also has label control for this weed Alternatively, try other tough formulations of glyphosate (e.g. Scotts Roundup Ultra, Scotts Tumbleweed, Bayer Tough Rootkill, Doff Maxi Strength Glyphosate Weedkiller or Westland Resolva Xtra Tough Concentrate) Glyphosate is usually applied to the foliage and is passed within the plant to the underground parts It is useful to cut away old stems during the previous winter to allow good access. As with other weeds, the most effective time for spraying Japanese knotweed with glyphosate is at the flowering stage in late summer.

However, it is difficult to spray at this stage, when the weed is 2.1m (7ft) or more high A more practical approach is to allow Japanese knotweed to grow to about 90cm (3ft), which will usually be reached in May, and spray then. There will be regrowth and consequently a second application in mid-summer is useful. Check during September and if it has grown once more, spray again before growth begins to die down in the autumn. Check again the following spring Avoid spray coming into contact with garden plants. Glyphosate-treated knotweed will often produce small-leaved, bushy regrowth 50-90cm (20in-3ft) in height the following spring. This is very different in appearance to the normal plant and it is essential that this regrowth is treated It usually takes at least three to four seasons to eradicate Japanese knotweed using glyphosate. Professional contractors, however, will have access to more powerful weedkillers that may reduce this period by half Residual control The residual weedkiller Bayer Ground Clear Weedkiller containing glyphosate/flufenacet/metosulam comes in a soluble sachet.

It may provide a moderate check in growth, but because of the extremely persistent rhizomes, is unlikely to eradicate the weed Seeking help from the professionals Some professional companies offer Japanese knotweed removal. They can usually report on risk for mortgages with suggested treatment plans and offer insurance-backed guarantees where required. The British Association of Landscape Industries (BALI) has a directory of members offering invasive weed control . See our page on hiring contractors for more guidance. Download Weedkillers for gardeners (Adobe Acrobat pdf document outlining weedkillers available to gardeners; see sections 4 and 5) Other related species Several species of Persicaria and Polygonum, including Persicaria lapathifolia and Persicaria maculosa can also be troublesome weeds. Where possible, attempt control at the seedling stage by hoeing or using a contact weedkiller(e.g. Bayer Garden Ultrafast or Doff 24/7 Superfast Weedkiller). Once established amongst soft-stemmed plants (such as herbaceous border plants, bedding plants or vegetables) removal by hand or by hoe is the only safe approach. Download Weedkillers for gardeners (Adobe Acrobat pdf document outlining weedkillers available to gardeners; see section 3) Links

Question: `Fallopia japonica' is a perennial weed, very difficult to eradicate. How is it better known?
Answer: JAPANESE KNOTWEED