ABC's of Gardening: Flowering dogwood versatile ornamental

Q. I just purchased a flowering dogwood. How do I take care of it? — Tom, White Lake

A. The flowering dogwood (Cornus florida) is native to much of the eastern half of the United States. It can be grown wherever the winter temperature does not normally go below minus 15 degrees F.

Dogwood is a versatile ornamental tree. As a landscaping plant it is as suited to one-story houses and small yards as it is to large estates. It is adaptable to several types of soil, though it grows best in a moist, fertile loam that is slightly acid. Its primary demands are good soil drainage and protection from drought.

When it grows in the open in full sunlight, dogwood normally reaches a mature height of 12-15 feet. In shade or when crowded by other trees, it grows somewhat taller and does not flower as freely as it does in full sun.

Most of the flowering dogwoods that are sold are either the white-bracted wild form, Cornus florida, or the pink-bracted form, C. florida rubra. Several other forms are sometimes available. C. florida Rpendulas has weeping branches; Rpluribracteatas has double flowers, and Rxanthocarpas has yellow fruits. All of the varieties of flowering dogwood are similar in their hardiness and cultural requirements.

The best time to plant dogwoods is in late winter or spring, before growth begins.

Dig a planting hole twice the diameter of the root ball. If the roots of the dogwood are balled and burlapped, you need not remove the burlap before setting the tree in the hole. After the tree is set, you can cut the twine around the top of the root ball and fold back or cut off exposed parts of the burlap.

Place the dogwood in the hole and pack soil under the root ball until the tree sits slightly higher than it grew in the nursery. Then refill the hole with a mixture consisting of equal parts of soil and organic matter, peat moss, well-decayed manure, or leaf mulch. Press the soil mixture firmly around the root ball and water thoroughly.

After the plant has settled, its depth should be about the same as it was before transplanting. Avoid planting too deep.

After planting, cover the soil beneath the branches with a mulching material peat moss, oak leaves, or forest litter. Apply a layer about 3 inches deep. Add new mulching material periodically to maintain the mulch. Mulch helps to keep the soil moist near the surface, where dogwood roots are most active. As the mulching material decays, it releases nutrients for use by the dogwood tree.

If you maintain an adequate amount of mulch around dogwood trees, few weeds should grow there. Those that do grow can easily be pulled by hand. Be careful if you use a hoe or other weeding tool around dogwoods; these implements may harm the shallow roots of the tree.

Normal rainfall ordinarily provides enough moisture for mulched dogwoods. During droughts, however, the trees should be watered at weekly intervals. When you water, soak the root area thoroughly. Be careful, however, that you do not drown trees growing in poorly drained soils.

If dogwoods are planted in reasonably fertile soil that is well supplied with organic matter, they seldom need fertilizing. Free blooming is promoted by moderate rather than quick growth.

If you want to stimulate growth of your trees after they have recovered from transplanting, or if they show signs that the soil is infertile, you can apply the same fertilizers that you use for your lawn or garden. Apply them from late winter through early summer. Signs of low soil fertility are small, sparse, pale leaves and short twig growth. Do not place fertilizer near the trunk.

Dogwoods seldom need pruning, except for removal of dead, injured, diseased, or insect-infested parts. Make pruning cuts back to a crotch.

Poor appearance of dogwood trees often is because of factors other than disease. Poor planting site, low soil fertility, heat, or drought can cause your tree not to thrive. A few diseases affect dogwood, however. Some of them are temporarily disfiguring but have no lasting effect on the trees.

Susan M. Dollard is the Master Gardener program coordinator at the Cornell Cooperative Extension of Sullivan County.