Description:
This tree is 40-65' tall at maturity, forming either a single trunk
about 1½-3' across or developing multiple trunks. The crown is
relatively open and irregular. On older trees, trunk bark is gray and
rough-textured from coarse irregular furrows, while on young trees it
is greenish yellow to golden brown and relatively smooth. Branches and
twigs are greenish yellow, golden yellow, or golden brown,
while young shoots are light green;
the twigs and shoots are relatively slender and flexible. Alternate
leaves about 2-4½" long and ¼-¾" across occur along the twigs and
shoots; they are narrowly
elliptic or narrowly lanceolate in shape and finely serrated along
their margins. The upper surface of mature leaves is medium green
and glabrous, while the lower surface is somewhat whitened, glabrous,
and glaucous. Young leaves are yellowish green and they may have a few
fine silky hairs. The narrow petioles are pale yellowish green and up
to ½" long. At the bases
of these petioles, pairs of stipules are either absent or
early-deciduous.
Golden Willow is dioecious, producing male (staminate) flowers and
female (pistillate) flowers on separate trees. These flowers are
arranged in narrowly cylindrical catkins about 1-2½" long; the catkins
occur on short side shoots up to ¾" long that have 1-2 small leaves.
Each male
flower consists of 2 stamens (rarely 3) with yellow anthers. The
filaments of the stamens are hairy below the middle and hairless above.
Each female flower consists of a glabrous ovary on a short pedicel
(about 1-2 mm. in length) with a pair of stigmata above. The green
ovary is lanceoloid-pyriform in shape and 3-5 mm. in length. At the
base of each flower (whether male or female), there is a yellow floral
bract that is short-oblong in shape and hairy. The blooming period
usually occurs from mid- to late spring for about 1-2 weeks. Female
flowers become mature seed capsules about a month later, when they turn
brown and split open to release their tiny seeds. These seeds are
embedded in fine cottony hairs and they are distributed by the wind.
The woody root
system is abundantly branched and widely spreading.
Cultivation:
The
preference is full or partial sun, wet to mesic conditions, and fertile
soil is loamy or silty. This tree develops relatively rapidly, but it
is not
long-lived. The aggressive roots can clog underground water pipes and
sewer lines. This tree is attacked by numerous insects and disease
organisms. It is also prone to storm damage.
Range
&
Habitat: The introduced Golden Willow rarely naturalizes
in Illinois. Wild specimens of this tree have been found in
only a few counties of the state. It is native to Eurasia. Habitats
consist of
riverbanks, areas near drainage ditches, shorelines of ponds, edges of
floodplain woodlands, vacant lots, and roadsides. This willow can be
found in disturbed areas in cities, suburbs, and neighboring areas. It
is occasionally cultivated as a landscape tree because of its
attractive yellow bark.
Faunal
Associations: The flowers of
willows are cross-pollinated primarily by various kinds of bees and
flies. Both nectar and pollen are available as floral rewards. Several
Andrenid bees that can be found in the Midwest are oligoleges
(specialist pollinators of willows):
Andrena andrenoides,
Andrena
bisalicis,
Andrena
erythrogaster,
Andrena
illinoiensis,
Andrena
mariae,
Andrena salictaria,
and
Andrena sigmundi.
Other insects feed
destructively on the leaves, sap, catkins, and wood of these trees. For
example, the following leaf beetles are known to feed on White Willow
(
Salix alba),
of which the Golden Willow is a cultivar or variety:
Calligrapha multipunctata,
Chrysomela knabi,
Chrysomela scripta,
Crepidodera solita,
and
Plagiodera
versicolora. Other insect feeders
include the larvae of metallic wood-boring beetles, the larvae of
long-horned beetles, various kinds of weevils, the larvae of gall
flies, plant bugs, stink bugs, aphids, leafhoppers, thrips, katydids,
and the caterpillars of many moths. Caterpillars of the butterflies,
Limenitis archippus
(Viceroy) and
Nymphalis
antiopa (Mourning Cloark)
feed on willow foliage, as do caterpillars of the skipper,
Erynnis
icelus (Dreamy Duskywing).
Willows are an important resource to many
vertebrate animals. Beavers use the wood, bark, and branches of willows
as a source of food and construction material for their lodges and
dams. The buds and/or catkins are eaten by the Ruffed Grouse, Red
Squirrel, Fox Squirrel, and Gray Squirrel during the spring when other
sources of food are limited. Both White-Tailed Deer and Elk browse on
the twigs and leaves, while the Cottontail Rabbit gnaws on the bark of
young trees and the Meadow Vole feeds fallen catkins. Because
willows are host plants of a large number of insects, insectivorous
songbirds often forage among their branches and leaves. These trees
also provide nesting habitat for such birds as the Yellow Warbler,
Warbling Vireo, and Rusty Grackle.
Photographic
Location: Along a drainage ditch in Urbana, Illinois.
Comments:
The yellow bark of Golden Willow is very unusual in appearance and
interesting. There are some differences of opinion among authorities
whether this tree should be considered a variety or a cultivar of
Salix
alba (White Willow). The typical variety (or cultivar) of
White Willow differs from
Golden Willow by having brown branches and twigs and leaves with
white-hairy undersides. The Golden Willow should not be confused with
the hybrid,
Salix ×
sepulcralis (Golden Weeping Willow), which has
strongly drooping branches. The Golden Weeping Willow is probably a
hybrid between the Golden Willow and
Salix babylonica (Weeping
Willow). Like the Golden Willow, Golden Weeping Willow has
striking yellow
bark on its branches and twigs.