Description: This introduced perennial vine becomes woody with age and can reach 60' in length. The young stems are green, pubescent, and round, becoming purplish brown and glabrous with age. The opposite leaves are up to 3" long and 1½" across. They are oval or ovate, smooth along the margins, and evergreen. Young leaves are slightly pubescent and ciliate, while older leaves become glabrous. Each leaf has a short petiole that is also pubescent while young.
From the axil of each leaf, there is one
or two flowers on short petioles. Each flower is about 1–1½" long,
consisting of a long tubular corolla with upper and lower lips, 5 strongly
exerted white stamens with light tan anthers, a strongly exerted white style
with a knobby green stigma, and a small calyx with 5 teeth that is green and
pubescent along its outer surface. The corolla is initially white, but become
tannish yellow with age. It has a long upper lip that curls upward and
terminates into 4 narrow lobes, while a long lower lip curls downward and
terminate into a single narrow lobe. The tubular base of the corolla is finely
pubescent on the outer surface. At the base of each flower, there is a pair of
leafy bracts. Each bract is up to 1" long, ovate, and slightly pubescent. The
blooming period usually occurs during the summer and lasts about 2 months. The
flowers have a delightful honeysuckle fragrance that is quite strong. Each
flower is replaced by a black berry about ¼" across that contains 2-3
flattened seeds. The seeds are pointed at one end and well-rounded on the
other. The root system produces rhizomes, which enables this plant to spread
vegetatively. Japanese Honeysuckle can climb adjacent woody vegetation,
otherwise it has a tendency to sprawl across the ground in disorderly
heaps.
Cultivation: The preference
is partial sun, moist to mesic conditions, and a fertile loam to support the
rampant growth. This plant is very aggressive, and can smother shrubs and small
trees.
Range &
Habitat: Japanese Honeysuckle is common in southern Illinois,
occasional in NE and east central Illinois, and uncommon or absent elsewhere.
It was introduced into the United States from east Asia as an ornamental plant.
Habitats include floodplain woodlands, thickets, seeps, limestone glades,
power-line clearances in woodland areas, semi-shaded areas along roadsides and
railroads, and edges of yards. Because of the attractive flowers, this plant is
often cultivated in residential areas. It occurs in both disturbed and natural
areas, and has the capacity to displace many native species of plants in
woodland areas.
Faunal Associations:
The nectar of the flowers attracts hummingbirds, Swallowtails and other
butterflies, and Sphinx moths (including Hummingbird moths). The caterpillars
of the moths Hemaris thysbe (Hummingbird Moth) and Callizzia
amorata (Gray Scoopwing) feed on the foliage. The foliage is also eaten by
many mammalian herbivores, including the Cottontail Rabbit and White-Tailed
Deer. Various upland gamebirds and songbirds eat the berries, including the
Wild Turkey, Bobwhite, Eastern Bluebird, Purple Finch, Eastern Goldfinch,
Slate-Colored Junco, and Hermit Thrush. These birds distribute the seeds far
and wide. The dense vines and foliage help to provide cover for small mammals
and nesting habitat for some species of songbirds.
Photographic Location: Edge of a yard in Urbana,
Illinois, where the vine smothered a shrub.
Comments: While the flowers and foliage are quite
attractive, Japanese Honeysuckle is one of the worst invaders of woodland areas
and thickets. On the positive side, it is moderately valuable to various fauna,
as indicated above. It is easy to distinguish Japanese Honeysuckle from other
Lonicera spp. (Honeysuckles), as the latter are shrubs or much shorter
vines. Other Honeysuckle vines terminate in a small cluster or interrupted
spike of flowers. Their terminal leaves surround the stem and merge together at
the base (they're connate). Japanese Honeysuckle usually produces axillary
flowers; when terminal flowers are produced, they occur in a panicle. The
flowers of Japanese Honeysuckle are larger in size (1" in length or more) than
the flowers of other Honeysuckles, with the exception of Lonicera
sempervirens (Trumpet Honeysuckle), which has bright orange-red
flowers.