Throughout the northern hemisphere of the world, close to 50 varieties of dogwoods (Cornus) exist. In the United States 17 grow. Around 80 cultivars now exist and most are available in variegated leaf form, according to the University of Tennessee. Dogwoods grow as large, multi-stemmed shrubs or as small to moderate size trees.
In leaves, chlorophyll produces the varying shades of green color. Variegated leaves occur when a tree is bred to produce mutations in chlorophyll production. The varying layers of the cell tissue of the leaf will show varying effects, which create cream- or white-colored variegation to occur, mixed with areas of the leaf that contain ample chlorophyll to maintain its green coloration. To produce yellow or cream variegation, some yellow pigment must exist within the leaf. When all pigments are bred out of the leaf, the color is a pure white.
Maintaining the Dogwood's Variegation
Plant variegated dogwood trees in full sunlight to maintain their variegation color. When planted in the shade the green pigmentation will take over the leaf and soon the variegation will begin to disappear. Even partial shade will result in a less dramatic variegation appearance on the dogwood.
All variegated dogwood trees and shrubs grow slower than green leaf varieties. Variegated leaf varieties contain less chlorophyll than their green leafed relatives. The lack of chlorophyll causes leaves and buds to develop slowly. Variegated cultivars often show instability in their growth patterns and they will often develop shoots that contain all green leaves. These must be promptly removed to maintain the tree's overall appearance. Due to the variegated tree's lack of chlorophyll, the tree is the first to show brilliant fall colors each year.
Variegated dogwood trees that experience stress will often show leaf scorch on the white of the variegation. Try to maintain the tree's overall health with regular watering. Dogwoods enjoy moist, well-draining soil conditions. Begin fertilizing the dogwood tree in its second year of life. Fertilize in the spring with a well balanced 10-10-10 or 12-12-12 fertilizer. A good rule of thumb is to apply 1 cup of fertilizer for every inch of diameter in the tree's trunk. Apply the fertilizer when the buds of the tree first appear.
Dogwood trees require very little pruning. Each spring remove any dead or damaged wood. Low limbs can be removed if they impend walkways or other areas. Most dogwoods want to grow with multi-trunks. The lower stems can be pruned away to maintain a singular trunk or allowed to grow. The tree can be pruned prior to flowering or during flowering. Apply 2 inches of mulch around the base of the dogwood tree to keep unwanted weeds at bay and also help the soil retain water. Apply 1 inch of water per week during the summer if there is not ample rainfall, according to the National Gardening Association. Adequate water will help insure the variegated dogwood maintains its health and appearance.