Invasive plant

Question: Invasive plant taking over our garden. Started in the wood chip pile; spreading into the walkways and beds. See attached photos from last summer. I've been digging it by hand -- the roots are long and aggressive and it's spread several yards in every direction. It's even popping up in disconnected areas far from the main infestation. Questions:
1. What is it?
2. What's the best way to get rid of it? For example, do I need to put down plastic and try to cook it? We garden organically, so I want to avoid Roundup, etc.
3. Can I compost it?
Any guidance appreciated.

responder: Enrique Peredo, UVM Extension Master Gardener Volunteer www.uvm.edu/extension/mastergardener  Replied May 22, 2023, 7:08 AM EDT
response: Thank you for contacting the UVM Extension Master Gardener Helpline. This aggressive plant that you're dealing with is commonly called horsetail.  It likes moist and acidic soil probably the right conditions in your paths.  The following link from Purdue University Extension identifies it and illustrated how it reproduces itself by spores and as you've discovered runners below the soil surface.   https://www.extension.purdue.edu/extmedia/ws/ws-29-w.pdf It is a very difficult native invasive to control, even surviving the application of herbicides.   This next link is a response made by on of my colleagues addressing horsetails.  It may help you strategies how to at least control its spread. https://ask2.extension.org/scp/tickets.php?id=828722  This last link from the University of Maine Extension.  The question starts as yours does, 'getting rid of horsetails'.  Some of the key points here is making sure your soil ph is suitable for the plants you want to grow. This can be determined by doing a soil tests. Improving drainage in the soil and targeting just the garden beds when watering could also help.  Do not till the area nor compost any of it.   Pulling out the top grove repeatedly may be the best way to weaken it and its spread.  Long term option is to cover the whole area where it is present with a black tarp although it may be several years before it is irradicated.  https://extension.umaine.edu/gardening/2021/06/01/horsetail/ Success to you.

responder: The Question Asker Replied May 22, 2023, 1:41 PM EDT
response: Thanks, this is helpful. I need authorization to open the second link: Email or Username and Password. AR  On 5/22/2023 7:08 AM, Ask Extension wrote:

responder: An Ask Extension Expert Replied May 23, 2023, 7:43 AM EDT
response: Hi Andy:  Here is the info. from the second link.  Lisa   Horsetail is one of the most difficult plants to remove and control. It sounds like it's just starting in your garden so that is to your advantage. I researched this topic and this was the best answer I found from the university of Maine Extension.  Rebecca Long, Agriculture and Food System Professional Horsetail is a tough one! Adjusting pH alone is unlikely to be a solution, while horsetail may prefer acidic conditions, it can grow in a range of conditions so if you raised the pH high enough to be totally inhospitable for horsetail, it would likely be unsuitable for most  plants. Here are some approaches you could take, unfortunately, none of them are quick or easy. 1. Test the soil and adjust pH and fertility as recommended. While this alone is unlikely to be enough, this step will help ensure that the site is suitable for the plants you want and help them out compete weeds. 2. Horsetail likes wet conditions so if you can, improve drainage or adjust your irrigation  practices to focus on just watering desirable plants (soaker hose or a drip irrigation system could help). 3. Avoid tillage, since horsetail spreads by rhizome. 4. Employ a strategy to exhaust the plants energy reserves: One option is repeated pulling/mowing/hand cutting of the stalks as they appear. This would need to be done multiple times per year, perhaps 5 -6 times. Don’t compost plant parts. The other option would be to shade out the plants with cardboard, a tarp, ground cloth, or by densely planting large plants. This may take several years, vigilance, and trying several of these approaches together. Herbicide options have limited effectiveness and application is difficult around desirable plants.    Here is another answer from Washington State University Extension:  Horsetail, (Equisetum arvense L.), belongs to a prehistoric plant family that was dominant in the world 230 million years ago and significantly contributed to the formation of coal deposits. The Pacific Northwest is home to about 20 Equisetum species. Horsetail is a perennial plant that grows from underground tuber-bearing rootstocks. It is unique in that it has two types of stems and growth habits. Field horsetail does not produce flowers or seeds.  For reproduction it relies heavily on its extensive, creeping root system and to a lesser extent on spore production. Fleshy tubers arranged at joints of the deep-penetrating rhizomatous root system store energy reserves (carbohydrates) and provide the plant with a remarkable regenerative capacity. Field horsetail thrives in acidic, poorly drained sandy or gravelly soils and full sun. Although it is considered a wetland plant, it can also be found in drier areas. Control Methods Cultural Control: First, improve the drainage, then raise the pH by applying dolomite lime at the rate recommended on the package. Wait at least two weeks before  increasing your soil’s fertility by adding fertilizer, since lime and fertilizer tend to cancel each other out if applied together. Because horsetail does not respond to nitrogen fertilization and wants sunlight, its growth can be suppressed through the use of a fertility program and competitive cover crops. Other control options that have met with some success include use of inorganic mulches and weed barrier fabrics. Improving drainage in the area can also be helpful. Mechanical/Physical Control: The tenacious root system of field horsetail makes it very difficult to control, particularly when using mechanical methods that can actually worsen the problem by spreading rhizomatous pieces that can regenerate. The fertile horsetail stems should be cut or burned before they form spores in order to reduce spread potential. Repetitive tillage or mowing over at least a 2-year period may be effective if timed to eliminate regrowth before the plants are able to replenish their energy reserves—shortly after emergence and before reaching 8 inches in height. Shallow tillage is not recommended. As is the case with most invasive  plants, the most effective management approach will involve a combination of methods, such as applying herbicides after mowing. Chemical Control: Few herbicides have any effect on field horsetail and their use depends on the situation in which it grows. In non-food areas, diclobenil (Casaron) is labeled for field horsetail use. Multiple chemical treatments may be necessary but cannot be applied by a homeowner, you  must be a licensed applicator. Reference: http://extension.wsu.edu/whitman/wp-content/uploads/sites/28/2013/11/Horsetail2010_000.pdf?x11869

responder: The Question Asker Replied May 23, 2023, 10:00 AM EDT
response: Thanks!  On 5/23/2023 7:43 AM, University of Vermont wrote: