Description: This shrub is up to 25' tall, developing widely spreading branches that are often arranged in tiers. The trunk bark of older shrubs is light brown and slightly rough; it has furrows that are shallow and narrow. The trunk bark of younger shrubs is more smooth and pale greenish brown. Alternate leaves are located toward the tips of small branches and twigs; they are spaced closely together, sometimes appearing opposite or whorled.
The leaf blades
are 2-5" long and about one-half as much across; they are ovate in
shape and smooth along their margins. The upper leaf surfaces are
medium to dark green and glabrous, while their lower surfaces are pale
green to white and canescent (very short fine hairs). Leaf venation is
pinnate; for each leaf blade, there are 5-6 curving lateral veins on
each side of the central vein. The slender petioles of the leaves are
light green to red and up to 1" long. Flat-headed panicles of flowers
are produced from among the leaves. Each panicle spans about 2–3½"
across and contains numerous small flowers that are cream-colored to
white. Each flower is about ¼" across, consisting of a 4 narrowly
lanceolate petals, a tiny calyx, 4 stamens, and a central style. The
petals spread widely from the center of each flower, drooping downward
somewhat later. During the
blooming period, the
branches of the panicle
are
light green. The blooming period occurs from late spring to early
summer and lasts about about 2-3 weeks. The flowers have a pleasant
fragrance. The flowers are replaced by small drupes about 1/3" across
that become ripe during the early fall. At this time, the drupes are
dark blue and the branches of the panicle are orange-red. Each fleshy
drupe contains a single large seed (or sometimes two). Ripe berries are
sour and bitter. The root system is woody and branching. This shrub
reproduces by reseeding itself.
Cultivation:
This shrub prefers partial sun, moist well-drained conditions, and a
rich loamy soil that is somewhat acidic. It also adapts to full sun and
light shade. Growth and development is rather slow.
Range & Habitat:
Alternate-Leaved Dogwood is found mostly in the northern half of
Illinois, where it is uncommon. In the southern half of the state, it
is rare or absent. This shrub is native to the state. Habitats include
mesic deciduous woodlands, mixed
woodlands (both coniferous & deciduous trees are present),
woodland borders and openings, thickets, and shaded or partially shaded
banks of streams. This shrub is normally found in high quality natural
areas. It is often cultivated as an ornamental landscape plant.
Faunal Associations:
The nectar and pollen of the flowers attract many kinds of insects,
including long-tongued bees, short-tongued bees, wasps, flies, and
butterflies. The short-tongued bee, Andrena fragilis,
is an oligolectic visitor of the flowers. Many insects feed on the
leaves, wood, and other parts of Cornus spp.
(Dogwood shrubs). These species include moth caterpillars (see Moth Table),
caterpillars of the butterfly Celastrina argiolus
(Spring/Summer Azure), long-horned beetles, leaf beetles, plant bugs,
aphids, and other insects (see Insect Table). The berries are a
popular food source of many birds (see Bird Table);
they are also eaten by the White-Footed Mouse and Eastern Chipmunk.
White-Tailed Deer and the Cottontail Rabbit feed on the leaves and
twigs, while Beavers feed on the branches of this shrub when it grows
near sources of water.
Photographic Location:
Meadowbrook Park in Urbana, Illinois.
Comments: A well-developed specimen of this attractive shrub has branches that are arranged in horizontal tiers, somewhat resembling the multiple roofs of a pagoda. As a result, it is sometimes referred to as the 'Pagoda Dogwood.' This is the only Cornus sp. (Dogwood) in Illinois that has alternate leaves; others species in this genus have opposite leaves. Alternate-Leaved Dogwood has 5-6 conspicuous lateral veins on each side of the central vein of a leaf; the leaves of other Dogwood species usually have fewer lateral veins that are less conspicuous. The color of the ripe berries is also useful in making an accurate identification, as Alternate-Leaved Dogwood has dark blue berries, while other Dogwood species in Illinois usually have berries that are white, red, or pale to medium blue.