The sight of dogwoods in full bloom, highlighted against the darker backdrop of a wooded lot is one that is not easily forgotten. Dogwoods are highly regarded for their all-season interest and especially for their spectacular spring bloom.
We live close to the western limit of where the common flowering dogwood naturally grows. Flowering Dogwood, botanically known as Cornus florida, is native to the United States from southern Maine south to Florida, west to eastern Texas and Kansas. There are several other species in the dogwood genus Cornus, but none is as widely adapted and grown in the south as the flowering dogwood.
The genus name “Cornus” means horn and refers to the very hard wood of the tree. Years ago the hard wood of dogwoods was valued for use in golf clubs, pulleys, engraving blocks and tool handles. Nowadays, dogwoods are prized for the outstanding display of white or pink bloom in early spring when the azaleas and wisteria bloom.
The species name “florida” does not refer to the State but rather an abundance of bloom, which describes dogwoods well.
The common name “dogwood” comes from England where a concoction was made out of the bark a related species to wash mangy dogs. Somehow, the unflattering name stuck.
Dogwoods have been cultivated for landscape use since the 1700′s. In the late 1800′s, a white dogwood was found in Philadelphia with a single branch bearing pink flowers. From that one branch most of the pink and red varieties have descended.
Many outstanding varieties have been developed over the years (well over 100). A few of the more popular ones include ‘Cherokee Chief’ with ruby red flowers, ‘Cherokee Sunset’, a red variety with variegated leaves of pink, green and white, ‘Cherokee Daybreak’, a white selection with variegated leaves, ‘Cherokee Princes’, ‘Cloud 9’ and many, many others.
What are often referred to as the flowers on a dogwood are actually modified leaves called bracts. The tiny, true flowers are clustered in the center of the white bracts.
Dogwoods are valued not only for their spring bloom, but also for their year-round interest. The manner in which the branches grow horizontally provides the landscape with a unique dimension. In the fall, green leaves turn a colorful orange-red, which highlights clusters of bright scarlet fruit which birds relish. In the winter, the scaly bark of the trunk is unmistakable, looking similar to alligator skin.
Dogwoods are typically found as understory trees. They can get up to 40 feet tall, and some specimens have been recorded to be over 150 years old, although they typically have a much shorter lifespan in our area. According to the Texas Forest Service – Texas Big Tree Registry, the Texas Champion Flowering Dogwood is located in Rusk County, measuring at 75 feet in circumference, 38 feet tall, with a 32 foot crown spread.
Dogwoods do best in a well-drained, slightly acid, sandy loam soil which is why they do well in East Texas. Although they seem to grow best in a partially shaded location, many can be found in full sun, provided the soil conditions and moisture are just right. The abundance of blooms is related to the amount of sun received.
When planting dogwoods, dig the hole no deeper than the root ball and about twice the diameter of the ball. Compacted soil should be loosened with a tiller in a 5 or 6 foot diameter to speed root growth into surrounding soil. There is no need to amend the backfill if the soil is well drained.
Both newly planted dogwoods and older established trees should be well mulched with pine needles, pine or cypress bark or other material. The larger the area covered by mulch the better. Mulch reduces competition from weeds and grass, keeps the soil cooler and more evenly moist which dogwoods prefer, and also prevents accidental injury from mowers and string trimmers. Keep the mulch off of the trunk, however.
Injuries from lawn maintenance equipment not only physically damages the tree, but also creates an open wound attractive to diseases and borers, especially the dogwood borer which can girdle the tree, causing it to die back.
Dogwoods have relatively shallow roots. Supply supplemental irrigation in the summer and fall if rainfall is short. Leaves should not be allowed to wilt, resulting in stress.
Although dogwoods are hardy here, they are susceptible to stress from varying sources. Drought, too much water (flooding, poorly drained soils), too much fertilizer, and herbicides are some common stress factors. Stressed trees are susceptible to various types of borers and root rots which can lead to further problems.
Dogwoods do not need much fertilizer, and are quite sensitive to herbicides, so care must be taken for dogwoods growing in maintained lawns.
Some folks may have heard of a disease which is killing many dogwoods on the east coast. The disease is called dogwood anthracnose, and causes leaves to burn on the edges, lower limb die back and eventual death of tree. Fortunately, this disease does not seem to do well or occur in Texas or in nearby states. Dieback on our local trees is usually due to various stress factors occurring over a period of years, coupled with dogwood borer injury and other insects and diseases.