INTRODUCTION

The natural range of dogwoods extends from

Maine to the Gulf of Mexico. The trees color cities

and countrysides white with dazzling displays in the

early spring.

Although they are most spectacular in spring, part

of the attraction of dogwoods lies in their year-round

beauty. They are truly a four-season plant, displaying rich green luster in the summer followed by deep

red leaves in the fall. Bright red clusters of seeds decorate the tree in the winter months.

The native dogwood, Cornus forida, is a small,

bushy tree reaching 15 to 30 feet in height. Its short

trunk has several large, wide spreading branches

forming a dense rounded crown. Dogwoods usually

grow best in the shade of other hardwoods.

A wide variety of dogwoods is available. The Bay

Beauty is more tolerant to drought and heat than are

other varieties and can be planted in full sun with

better results than the native dogwood. Other cultivars have been developed to highlight different characteristics. Cherokee Chief has deep red flowers

while Plena has white semi-double flowers. Rubra

is the original pink dogwood, and Fragrant Cloud

boasts slightly scented white blossoms. Another dogwood to consider is the or Japanese dogwood. It is

similar to the native dogwood except that it’s petallike flower bracts are pointed (rather than notched),

and it blooms from late April through May after full

foliage has been attained.

All dogwoods have the potential to flower. The age

at which they begin flowering will vary with genetic

differences and site conditions. Generally, it takes 3

to 5 years before the first flowers are produced, then

flowering recurs almost yearly with a heavy crop

about ever other year.

Dogwoods are a valuable and enduring asset to

any homeowner’s property. This brochure presents

the main points to consider when you select your

dogwood, and how to maintain it in good health for

many years. If you have any questions, contact your

local nursery, your State forestry agency or Cooperative Extension Service.
SOURCES OF PLANTS SOURCES OF PLANTS

Dogwoods grow widely on most sites in the East,

if you want additional dogwoods, the source of your

new trees will he important in getting and maintaining

healthy plants.

Buy your tree from a local nursery. This source

ofters you the best prospects for a healthy tree. inspect all trees carefully. Avoid trees with broken or

dead branches, trunk damage or leaf spots, all of which

indicate unhealthy trees.

Digging plants trom the wild is not a good idea.

Wild dogwoods may transmit insects and diseases to

healthy trees.

PLANTING SITE PLANTING SITE

Dogwoods naturally grow as an understory plant in

forests where organic material and natural surface

mulch are present. When planted in poorly drained

areas, dogwoods do not grow well and may even die,

If dogwoods are not properly planted and cared for,

they will grow poorly when exposed to full sun. Marginal leaf burn or scorch often result from this condition. Good planting sites should have at least partial

shade. Avoid areas where the soil is often wet.

Preparing the planting site properly is extremely

important. If this is not done at the outset, then poor

growth will result. Dig a hole at least 18 inches deep

and 3 feet in diameter, regardless of the tree size. Current research has shown that the addition of soil amendments to the planting hole is unnecessary. In most

cases, the soil removed from the planting hole is sufficient for good tree growth.

It is very easy to plant trees too deep. Dogwoods

are very shallow-rooted plants, so avoid planting your

tree deeper than it grew in the nursery.

Potted or container-grown dogwoods can be planted

any time if they are watered regularly. Balland-burlap

and bare-root trees should be planted from November

through April. Prune off only broken or damaged

branches for the first few years so that a good root

system can be established.
MAINTENANCE OF MAINTENANCE OF

ESTABLISHED TREES ABLISHED TREES

Healthy dogwoods usually result from regular,

etfective maintenance programs. Watering, fertilizing,

pruning, and mulching are vital components of a good

maintenance program.

In the absence of regular rainfall, dogwoods will

need supplemental water during the summer and tall,

Watering once a week, in the morning, with a soaker

hose is recommended for their shallow root systems.

The soil should be watered to a depth of 6 inches.

Watering with a sprinkler is not recommended because

it wets the foliage, creating ideal conditions for certain diseases.

Dogwoods in natural areas usually do not require

fertilization. However, trees in yards and restricted

growing sites can benefit from a suitable fertilizer.

Soil testing is recommended to determine fertility levels and application rates. Broadcast fertilizer on top

of the soil. Fertilize trees in late spring or early summer after leaves complete expansion. Never use fertilizers containing weed killer, Always thoroughly

water the area after fertilization.

Regular pruning serves many purposes. Removing

dead and diseased branches helps prevent the spread

of disease and insect pests, Pruning improves the tree’s

structure as well as its appearance, With a few exceptions, winter is an excellent time to prune your tree.

All pruning cuts should be made with clean, sharp

tools and should be properly positioned and made in

the proper order. First, locate the tree limb’s branch

collar (see figure 1). Follow the steps shown for proper

pruning cuts. Pruning paint is not needed.

Figure 1 - Pruning guide.
Mulching is one of the easiest and most protective

things you can do for your trees. A mulch is used for

appearance, weed control, water conservation, erosion control and improvement of soil structure.

Mulches also insulate the roots from cold or heat.

Apply pine straw or bark 4 to 6 inches deep underneath the limb spread to achieve the above goals. A

mulch also reduces the need for mowers and string

trimmers next to the trunk, thus reducing injury from

these tools.

MECHANICAL INJURY

A common mechanical injury to dogwoods is

caused by I awnmowers hitting the base of the trunk

(figure 2). Such injuries invite basal stemrot disease

and insect borer infestation. Place a permanent barrier around the trunk to avoid injury.

Mulching around the base of the tree discourages

weeds and reduces the need to mow close to the trunk.

String trimmers pose a similar danger and will bruise

or girdle the cambium, the vital layer of tissue under

the bark. This damage is not easily detectable until

sudden tree decline or leaf drop result.

Dogwoods and other woody ornamental are very

susceptible to herbicides. Distorted yellowing leaves

can result from herbicide use. Browning or leaf scorch

may also be observed (figure 3).

Figure 2 - Lawn mowers and string trimmers cause

significant damage.
Spray equipment that has been used for herbicides

should not be used to apply insecticides or fungicides

to dogwoods.

In many cases, reduced growth results from chemical damage or mechanical injury. Discolored foliage

and scorched leaves are usually followed by branch

dieback and eventual death. Periods of stress brought

on by drought heighten these symptoms. Identify the

problem before attempting to solve it.

DOGWOOD DISEASES DOGWOOD DISEASES

Dogwood Anthracnose Dogwood Anthracnose

Dogwood anthracnose causes leaf spots, stem cankers, and kills shoots. Infected trees, if not properly

maintained, may decline. This disease should not be

confused with spot anthracnose.

Initial symptoms are medium-large, purplebordered leaf spots, and scorched tan blotches that

Figure 3 - Leafscorch is common on poorly managed

dogwoods.
may enlarge to kill the entire leaf (figure 4). Blighted

leaves often cling to stems after normal leaf drop in

the fall (figure 5). Trunk sprouts occur during the latter stages of disease development. The fungus infects

twigs and can grow down a limb and infect the main

stem (figure 6). Cankers that form on the main stems

can be detected when the bark is peeled back. Cankers are identified by distinct margins surrounded by

healthy cambium tissue (figure 7).

Dogwood trees that are adjacent to natural stands

of dogwoods may be more susceptible. Prune any

dead wood in the tree before disease reaches the main

trunk. Destroy the pruned wood to eliminate

Figure 4 - Leaf spots on dogwood caused by dogwood

anthracnose.

Figure 5 - Blighted dogwood leaves cling to branches

after infection by dogwood anthracnose.
any sources of fungus from the area. Water during

droughts, protect the root zone with a mulch and fertilize according to soil analysis. Avoid fertilizers with

a high nitrogen content. Fungicides registered for anthracnose on dogwoods can be used. These steps will

keep the disease incidence low.

Do not transplant dogwoods into urban areas from

trees dug in the woods. You may be transporting the

disease into an area where it did not previously

occur..

Spot Anthracnose Spot Anthracnose

Flower bracts are usually infected first, but this kind

of anthracnose also occurs on leaves, young shoots,

and fruit.

The initial symptoms are small, reddish-purple leaf

spots that are circular or elongated (figure 8). They

are first noticed in early spring. The spots are usually

%Sth inch in diameter (pinhead size). The centers are

yellowish, with brown or black margins. As additional

infections occur, the spots become numerous and eventually merge, forming larger leaf spots.

Severely infected flower bracts usually fall from

the plant prematurely. Those diseased bracts that do

remain on the tree are generally small and distorted.

Figure 6 (left) - Dead shoot and stem canker caused by

dogwood anthracnose.

Figure 7 (right) - Discoloration is evident when bark is cut

away from twighs infected with dogwood anthracnose.
Infection from the bracts then moves to the foliage.

The leaf spots are usually circular, although they

may be somewhat angular or elongated. The spot centers are yellow to grayish, with a dark purple border.

The centers will eventually drop out. Young shoots

and berries may develop elongated, scabby lesions that

have a distinct purple border.

Spot anthracnose is caused by the fungus, Elsinoe

corni. The fungus persists from year to year in infected twigs, fruit, and other tissues. If the weather is

dry before or during the flowering period, very little

disease will be observed. Infections will vary from

year to year because of this dependency on free moisture.

In most cases, fungicide sprays are not needed, as

this disease does not result in significant damage. If

fungicides are used, apply them from bud swell

through bloom.

Septoria Leaf Spot Septoria Leaf Spot

The symptoms of septoria leaf spot include medium

uniform, purplish spots, or lesions on the leaves. These

lesions do not retain the deep, purple border, although

the centers of these spots become grayish. This disease

occurs near the end of the summer. Stressed or weakened trees are more susceptible than those growing on a

natural site, or those in a healthy condition. Septoria leaf

spot is generally more of a problem when wet conditions persist and humidity is high.

Figure 8 - Spot anthracnose causes small, purple-bordered leafspots in the spring and may extend into the

growing season.
Botrytis Petal Blight etal Blight

Botrytis Petal blight is caused by the fungus,

Botrytis cinerea. This fungus affects foliage and green

shoots as well as petals. Disease is generally observed

during wet spring weather, often foIlowing winter

injury. The fungus reproduces on diseased tissue during periods of high humidity. Spores are spread by

wind and water.

Usually, this disease does not cause significant

damage to warrant application of any fungicide. The

best disease control is to keep plants healthy with ,

regular pruning, watering, mulching and fertilization.

Trunk Canker runk Canker

Basal trunk canker, caused by the fungus,

Phytophthora cactorum, is a major problem for urban dogwoods and is generally associated with low,

poorly-drained areas. Injuries caused by lawn mowers and insects are ideal sites for fungus infection.

The leaves of infected trees are stunted and generally turn red prematurely. The basal portion of the

trunk sinks, causing constriction and decay. The bark

eventually peels away, exposing the wood. Some

bleeding from the canker can occur, and sprouting may

occur below this damaged area. Avoid injury to the

tree base, select proper planting sites and control insects to help reduce trunk canker disease.

INSECTS INSECTS

Insect damage to dogwoods is very common. Most

of the damage is considered minor; however, when

other stress conditions are present, damage can be significant.

Dogwood Twig Borer wig Borer

and Clubgall Midge and Clubgall Midge

Both of these insects cause tip dieback. Damage

usually appears as withering leaves on branch tips

during the growing season. For minor infestations

prune and destroy dead twigs and branches yearly.
Dogwood Borer Dogwood Borer

The dogwood borer is a common insect pest on

established dogwoods. The larvae of the borer enter

the tree through openings in the bark and feed on the

cambium layer of the tree. Most attacks occur around

basal wounds caused by lawn mowers and string trimmers. The best prevention for this insect is to protect

the trees from wounds.

TEN ESSENTIAL STEPS

TO MAINTAINING HEAL AINING HEALTHY DOGWOODS

1. Select healthy trees to plant.

2. Purchase trees from a reputable nursery; do not

transplant trees from the wild.

3. Select good planting sites to promote rapid foliage

drying.

4. Use proper planting technique

5. Prune and destroy dead wood and leaves yearly;

prune trunk sprouts in the fall.

6. Water weekly in the morning, during drought.

Caution—do not wet foliage.

7. Maintain a 4- to 6-inch deep mulch around trees;

do not use dogwood chips as a mulch.

8. Fertilize according to soil analysis.

9. Use proper insecticide and fungicide where

appropriate.

10. Avoid mechanical and chemical injury to trees.

Figure 9 - Clubgall midge produces spindle-shaped swelling on the twigs.
Prepared by

Kenneth R. Bailey, District Forester

Georgia Forestry Commission

Edward A. Brown II, Plant Pathologist

Cooperative Extension Service,

University of Georgia

USDA Forest Service, Southern Region

1720 Peachtree Road, NW

Atlanta, GA 30367-9102

This brochure has been published through the cooperative efforts of the following to clarify some dogwood diseases to the public and illustrate the benefits

of proper maintenance to growing healthy trees.

• Carson-Newman College, Jefferson City, TN

• Champion International Corporation,Stamford, CT

• Georgia Forestry Commission, Macon, GA

• Izaak Walton League of America

• Southern Appalachian Man and the Biosphere, a

cooperative of Federal agencies and a nonprofit

foundation

• Southern Nurserymen’s Association, Marietta, GA

• Tennessee Valley Authority

• U.S. Department of Agriculture, Forest Service,

Southern Region

• University of Georgia, Cooperative Extension Service, Athens, GA

• Your local nursery professional

ACKNOWLEDGMENTS ACKNOWLEDGMENTS

The authors acknowledge the review of this manuscript by H. Daniel Brown — USDA Forest Service,

Atlanta, GA; Robert L. Anderson — USDA Forest

Service, Asheville, NC; Dr. R.W. Roncadori — Plant

Pathologist, University of Georgia; Dr. Floyd Hendrix

— Plant Pathologist, University of Georgia; Dr. Kim

D. Coder, Extension Forester, University of Georgia.

April 1989, revised March 1991, PDF revised

June 1997