5. Lonicera maackii (Rupr.) Maxim. (Amur honeysuckle, bush honeysuckle)
Map 1425, Pl.
335 e, f
Plants shrubs
1.5–4.0(–5.0) m tall, the main stems erect or ascending, self-supporting. Twigs
moderately to densely pubescent with short, curved, sometimes more or less
tangled, unbranched hairs, the pith hollow. Winter buds ovoid, hairy. Leaf
blades 3.5–9.5 cm long, 1.5–4.0 cm wide, elliptic to ovate-elliptic, angled or
rounded to more commonly tapered at the base, tapered to a sharply pointed tip,
the surfaces (and margins) sparsely to moderately pubescent with fine, mostly
curved hairs, at least along the main veins, not glaucous, but the undersurface
light green to pale green. Flowers in pairs in the axils of the leaves on
current years growth (first-year wood), each pair at the tip of a stalk
2–5(–8) mm long (often appearing sessile at fruiting), the 2 bracts each 1–4 mm
long, free, linear, hairy, the pair of bractlets on opposite sides of each
flower 1/2 as long to about as long as the ovary, free, oblong-obovate to
nearly circular. Calyces with stalked glands and long, straight hairs, the
lobes 0.2–0.5 mm long, triangular. Corollas 15–25 mm long, strongly
zygomorphic, divided about 1/2 of the way to the base into 5 more or less
spreading lobes of about equal length, the upper lip shallowly 4-lobed, the
lower lip 1-lobed, the tube not or very slightly swollen or pouched on the
lower side near the base, white (sometimes pinkish-tinged toward the base of
the tube), turning yellow or orangish yellow after pollination or with age.
Stamens and style exserted from the corolla, shorter than the corolla lobes,
the style hairy. Ovaries free. Fruits 4–7 mm in diameter, orangish red to red.
2n=18. April–June.
Introduced,
scattered, mostly around urban areas (native of eastern Asia, introduced widely
in the eastern U.S. west to North Dakota and Texas, Canada). Bottomland
forests, mesic upland forests, bases and ledges of bluffs, and banks of streams
and rivers; also fencerows, gardens, railroads, roadsides, and shaded,
disturbed areas.
Luken and Thieret
(1995, 1996) reviewed the spread of Amur honeysuckle in North
America, from its first introduction in the late 1800s to its
establishment as a serious pest. So-called improved cultivars of L. maackii
were developed by the U.S.D.A. Soil Conservation Service beginning in 1960 and
the species was planted widely for erosion control, as a hedge or screen, and
for ornamental purposes through the mid-1980s, when its invasive potential was
first realized. In the Midwest, L. maackii
largely replaced other bush honeysuckles in the horticultural industry and it
remains available through some specialty nurseries today. Lonicera maackii
was first reported for Missouri by Mühlenbach
(1983) from the St. Louis railyards, but it
remains undercollected in the state (for example, it is a problem plant in the Kansas City metropolitan
area but is still undocumented from those counties). It has proven to be
aggressively invasive in most midwestern states and has become the dominant
species in the understory of many remnant wooded areas in and around cities.
More recently it has used rivers and highways as dispersal corridors and is
beginning to invade more rural portions of Missouri. Dense stands of Amur honeysuckle
leaf out earlier in the spring than other understory plants, reducing sunlight
required by spring ephemerals and germinating seeds of other species.
Similarly, the species remains green until after other woody species have
already lost their leaves. Because the plants strongly impact the structure of
forest understories, they have been implicated in changes in nesting patterns
of some native bird species, rendering the eggs and chicks more prone to
predation. Luken and Thieret (1995) further noted that the berries are mildly
toxic to humans but are strongly unpalatable.