Rough Leaf Dogwood (Cornus drummondii) of the Dogwood (Cornaceae) family is a small, deciduous tree with opposite leaves, open clusters of small white flowers, and striking, decorative white fruit. The genus name derives from the Latin for “horn” in apparent reference to the hardness of the wood. The specific epithet recognizes Scottish botanist Thomas Drummond (1790-1835) who collected plant specimens from the western and southern U.S. The species occurs from eastern Texas to southeast South Dakota, east to Alabama and Ohio. In Arkansas, occurrence is mostly statewide with a notable gap in the counties of the Gulf Coastal Plain––perhaps explained by undercollecting. Habitats include various dry to wet soils on sunny and shaded sites, such as woodlands, woodland openings and borders, stream banks, fence rows and abandoned fields. Rough Leaf Dogwood is abundant along the Arkansas River.
Trees grow to 15-20+ feet tall from shallow, spreading roots that sucker to produce clonal trees. Spacing of trees in a colony may be tight or open, as determined by the age of the colony, shading, and rockiness of soil. Trees on more sunny sites develop a dense, broad, leafy crown, while crowded or shaded trees become tall with only a few erect branches. Some branches may exhibit a fast rate of growth (1+ feet per year) reaching for light. Epicormic branches may sprout directly from the trunk.
New twigs, initially pale green with dense, short pubescence, become reddish on their sunny side over several years before becoming gray and glabrous with small white lenticels that roughen with age. Twigs are straight. As they mature, the thin bark becomes shallowly fissured, splitting into small rectangular plates aligned along the branch. Fissuring becomes more pronounced on expanding trunks, with plates remaining relatively small and fairly tight. Lenticels eventually become lost on the rough texture of the bark.
Overwintering, short, slender twigs (1-2 inches long) have small, valvate (2 scales in a praying-hand position) buds. With spring, twigs develop a terminal pair of opposite leaves and one to several pairs of lateral leaves. Most new-twig growth, both vegetative and reproductive, originates from terminal buds. Lateral buds often remain dormant or produce short-lived, stubby twigs. A reproductive twig’s terminal leaves subtend a floral cluster, as well as axillary buds. Vegetative twigs’ terminal pair of leaves subtend a single terminal bud. On sunnier sites, tips of robust twigs become congested with branches and inflorescence peduncles, making this architecture rather obscure.
The opposite, simple, ovate to elliptic leaves are about 4-6 inches long (including a 1-inch petiole) and 2-3 inches wide, with wedge-shaped (cuneate) to rounded or oblique bases and acuminate to abruptly acuminate tips. Leaves are green above and lighter below, with the sunny side of petioles becoming reddish. Pinnate venation is recessed above and expressed below, the secondary veins arching toward, but not reaching, the leaf apex. Both surfaces are pubescent, with moderately scabrous hairs above and softer hairs beneath––the upper surface feels slightly rough. Twigs and petioles are also hairy. In fall, leaves become orangish to purplish with distal leaves somewhat persistent.
The inflorescence, from May to June, to 4 inches wide and 2 inches long, comprises a broad, rather flat-topped panicle on one or a few floral stalks. Fifty to eighty small white to creamy white flowers terminate the twigs of the current year. The pubescent branching stalks and pedicels redden as the fruits mature to white.
Flowers, about ¼ inch wide, have 4 sepals, 4 petals, 4 stamens (filament + anthers), and one pistil (ovary + style + stigma). Sepals, petals (about 3/16 inch long), and stamens (also about 3/16 inch long) are attached at the summit of the inferior ovary. The oblong anthers, set see-saw fashion at the narrowing tip of the filaments, are elevated higher than petals and stigma. The flattened stigma is at the apex of the erect style. A prominent nectary encircles the base of the style.
In August and September, the immature green drupes become white and fleshy as the floral stalks, floral branches, and pedicels become reddish. Each drupe, a slightly flattened sphere about ¼ inch across, contains a single, smooth stone. A dark, rimmed depression with persistent sepals at the fruit’s apex marks the former attachment point of the petals and stamens.
In regard to gardens, Rough Leaf Dogwood has a strong suckering tendency and, for a single-trunk tree, would need continual sucker control. It will grow in the understory, but, depending on degree of shading, its structure may be sparse and flowering and fruiting may be limited. This small tree is ideal for a larger naturalized area, for property barriers, and bank stabilization. Its leafy growth, flower clusters, fruits and fall foliage can be showy. Fruits are highly prized by a wide variety of birds and mammals.
Five other dogwoods occur in Arkansas: 1) Alternate Leaf Dogwood (Cornus alternifolia) with alternate or whorled leaves and twigs as well as panicles of small white flowers and blue fruits, 2) Flowering Dogwood (Cornus florida) with showy white bracts surrounding a densely clustered flower head and red fruits, 3) Stiff Dogwood (Cornus foemina) with panicles of small white flowers and blue fruits, 4) Silky Dogwood (Cornus obliqua) with panicles of small white flowers and blue fruits, and 5) Gray Dogwood (Cornus racemosa) with panicles of small white flowers and white fruits. Of these, Rough Leaf Dogwood is most likely to be confused with Gray Dogwood which has a similar growth habit and inflorescence. However, Gray Dogwood is more shrub-like, has panicles that are about as tall as wide, and its leaves are less pubescent, with smooth upper adaxial surfaces and abaxial hairs being appressed.
Article and photographs by ANPS member Sid Vogelpohl