The Dogwood, Its History, And Why We Love It
In the cold climate where I, now a Floridian, grew up, nothing told us more definitively that winter is over than the arrival of the dogwood blooms. We would ride, in early spring, into the local woods. The dogwoods were a lace edging to the understory of the hardwoods and pines of New England. The horses were not impressed and were happy to gallop in the new warmth.
The Name Dogwood
No one is sure where it came from. There is a similar Celtic word that means a sharp spear. Dogwood is a dense hardwood. The botanical name Cornus means horn, like an animal horn.
Wherever it is native in the world, it lives naturally on the edge of a hardwood forest. Keep this in mind and try to duplicate those conditions if you can. Sun in the morning and a little afternoon shade will make them happy at your house.
Good companions for aesthetics and compatibility of growing conditions include Rhododendrons, Azaleas, Witch-Hazel, and Mountain Laurel.
The native dogwood Cornus florida, has attractions all year. It flowers in springtime in shades of pink or white. In late summer, the green leaves turn dark red, and red berries develop, which feed songbirds. In winter, the tree has an attractive silhouette. This tree ranges from the milder areas of New England south to North Florida and to Mexico.
This tree is hardy and beautiful. It is attacked, currently, by Dogwood anthracnose. There are newer cultivars that are more resistant to this disease. They tend to have larger flowers and more colorful leaves. Ask your local grower, garden center, and county extension service for the best and most local information for your garden.
These dogwoods are successful in zones 5-9 in the eastern part of the country. If the devastating disease, anthracnose (leaf blight) is present in your territory, you can plant the kousa or Cornelian cherry dogwood, instead.
The Pacific Dogwood is Cornus nuttallii. It grows between San Francisco and British Columbia, but not in the eastern part of the country; this is a more tender plant, rated to zone 7. It offers fewer selections than the Eastern version. Try North Star, Asconia, or Goldspot.
The Kousa Dogwood is native to China, Korea, and Japan. It is similar to the North American natives and blooms a little later. Its fall berries can be messy; they are rated for zone 5-8, blooms a little later in the spring, and are more resistant to disease and cold than the Cornus florida. Before choosing your tree, check with local experts for conditions in your local area.
The Cornelian Cherry Dogwood Cornus mas is a European Tree and grows in zones 5-8. The yellow blossoms arrive late, and the fruits can be used in jams.
The Giant Dogwood is also called the Wedding Cake Dogwood for its layers of variegated foliage. It grows in zone 5-8 and reaches heights of 25-30 feet, rarely to 50′. Once mature, it is low maintenance.
How to Use Dogwoods in Your Landscape
The trees’ variety in size and color can serve as a focal point, screen, or accent.
Dogwood trees prefer moist, well-drained soil, slightly acidic with organic matter. The quality of the drainage is particularly important for success.
In their natural state, Dogwoods are an understory tree that can be used as such. They perform best in partial shade but can tolerate full sun with sufficient water. The Chinese varieties tolerate the sun better than the American natives.
The timing of feeding is important to Dogwood. Feed in the spring and again in 3 months. Do not feed trees in their first year.
How To Test For Drainage
Dig a hole one foot deep and 8-12″ inches wide. Fill the hole with water and refill it 12 hours later. Time the drainage, the water should be gone in 2-3 hours. If it takes less than 2 hours or longer than ten the drainage is not adequate for dogwoods. In fact, many plants will not do well. In that case, you can amend the soil, or move the plant.
How To Plant It
Dogwood can be planted in early spring or early fall. Bareroot plants should be planted in spring.
Soak the new tree in water before planting. Dig the hole as deep as the root ball but three times as wide. Amend the soil and remove the tree from the pot carefully. Cut the pot away if needed and loosen the roots with your fingers. If the water drains well, make the top of the plant 1″ above the soil line. If the drainage is slow, raise the top 2-3″.
Holding the tree in place, fill the hole 1/2 way and soak slowly, then finish filling. Do not put soil on top of the plant; you can mulch the top. You can build a soil berm around the tree, which will help retain rainwater. If you choose to do this, leave it for about one year.
Dogwood requires little pruning. Prune in the fall about six weeks before they begin to drop their leaves. This should permit the bark to heal before they become dormant. Remove any dead or damaged branches in order to reduce the opportunity for disease. Use clean trimmers (rubbing alcohol works well) and cut on a forty-five-degree angle facing upward to encourage growth.
Pests and Diseases of Dogwood
Nothing can rob your pleasure in your garden more than plant disease. Dogwood can be injured by several. As with other plants, the best line of defense is good maintenance.
Dogwood Anthracnose is the most prevalent and dangerous. It is capable of killing large numbers of trees in the landscape. It is caused by a fungus called Discula destructiva. How expressive a name! it presents itself as spots on the leaves and flower bracts. The spots appear first on the lower branches of the trees and move upward. The spots are tan with purple edges. They develop dry brown margins or large blotches.
The infection then spreads, and brown, sunken areas occur (these are cankers)
How to Prevent and Treat
Observation is the first step in IPM (integrated pest management), and it is the best and easiest practice in the garden. Look at the plants often. It is a great way to drink morning coffee while walking in the garden. Look for changes every day. It is free and pleasant.
Plant disease-resistant varieties. Check with your local County Extension Service. This service will have access to the latest and most local research from your own state university.
This is the most devastating disease of dogwood. Mechanical and chemical aids will help. Remove any damaged leaves and branches from near the trees. Rake debris. Use fungicide sprays in early spring to protect the new buds. Follow the directions on the label.
Insects and Pests
Dogwood Borer is the larvae of a clearwing moth that looks like a wasp. They need to find a wound or opening in the bark to do the damage. Healthy maintenance is the best defense and reduces the need for chemicals. If needed, use a product labeled for the borer.
Dogwood club ball midge-here, a small fly lays its eggs on the tree, and the gall develops. An early symptom is a wilted and deformed leaf. Cut off and burn the affected branch.
Scales- are immobile, small, legless insects that look like small grayish bumps. Spray with horticultural oil in spring. This will smother the scales and their eggs. Make sure to cover all of the foliage. insecticides are a last resort as they can also kill predators of scale.
The Dogwood tree is an addition to your garden with a four-season appeal. You can use it as a specimen in small groupings around the house, near the patio, or lawn. Also, it is effective in borders and in woodland gardens. It is valuable in a garden designed to attract pollinators and to support wildlife. Your songbird population will grow. The tree belongs in your naturalized areas. Enjoy it every season.