Description: This shrub is about 6-20' tall, forming single or multiple trunks. Most branches are erect to ascending and little-branched. An older shrub forms a gray-brown bark near the base that is slightly rough and fissured, while the bark of upper branches and twigs is reddish brown to brown and smooth. Actively growing stems are yellowish green to light green
and either smooth, slightly pubescent, or densely pubescent (rarely the latter). The alternate leaves of these stems are up to 4" long and 1½" across; they are ovate to narrowly ovate in shape and irregularly crenate-serrate to nearly smooth along their margins. The upper leaf surfaces are medium to dark green and hairless, while their lower surfaces are hairless, glaucous, and whitened. Shrubs with pubescent leaf undersides are probably hybrids. The slender petioles are up to ¾" long and glabrous to slightly pubescent. At the base of some petioles (particularly for vigorously growing shoots), there is a pair of large stipules up to ¼" long and across; these stipules are somewhat cordate in shape and either crenate-serrate or moderately lobed. On second-year twigs, catkins of either male or female florets develop from sessile scales. Pussy Willow is dioecious, with either all male or all female florets on separate shrubs. As the male catkins begin to open, they are covered with dense hairs that are silky gray. Shortly later, they become larger in size (up to 1" long) and yellowish in appearance from many stamens. Each male catkin consists of a dense mass of male florets; each floret has 2 stamens. The female catkins are spike-like racemes of female florets; these greenish catkins are 1-4" long at maturity. Each female floret consists of a pistil with a pair of tiny stigmata at its apex; the pistil is narrowly lanceoloid and canescent. The blooming period occurs from early to mid-spring for about 2 weeks. The female florets are replaced by seed capsules about 1/3" (6-8 mm.) long. During the summer, these capsules split open to release tiny seeds with cottony hairs. These seeds are distributed by wind or water. The root system is woody, branching, and shallow.
Cultivation: The preference is full sun, wet to moist conditions, and sandy or non-sandy soil with some decaying organic matter. The easiest method of propagation is to cut off a branch and stick it into moist ground. The branch will eventually form leaves at the top and develop roots underground. It also possible to scatter the tiny seeds across the ground, but it will take longer to develop a mature shrub. Because the seeds remain viable for only a week or two, they must be sown immediately.
Range & Distribution: The native Pussy Willow is occasional in NE Illinois and uncommon or absent elsewhere in the state. Illinois lies along the southern range limit of this primarily boreal species. Habitats include openings in floodplain forests, soggy thickets, marshes, shrub swamps, fens, low areas along rivers and other bodies of water, wet prairies, and ditches. This shrub is found in both sandy and non-sandy habitats. In areas that are prone to invasion by trees, some disturbance is necessary to maintain populations of this species.
Faunal Associations: The nectar and pollen of the florets attract a wide variety of insects, including honey bees, bumblebees, little carpenter bees (Ceratina spp.), cuckoo bees (Nomada spp.), mason bees (Osmia spp.), Halictid bees (including green metallic bees), Andrenid bees (Andrena spp.), Ichneumonid wasps, ants (non-pollinating), sawflies, butterflies (Nymphalis spp., Polygonia spp., & others), various beetles, and various true bugs (Graenicher, 1900; Lovell, 1915; Krombein et al., 1979; Wilhelm & Rericha, 2017). Several Andrenid bees are speciaist pollinators (oligoleges) of willows (Salix spp.). Other insects feed destructively on various parts of Pussy Willow and other willows. These insect feeders include the larvae of metallic wood-boring beetles (Buprestidae), larvae of long-horned beetles (Cerambycidae), leaf beetles (Chrysomelidae), weevils (Curculionidae), larvae of leaf-mining flies (Agromyzidae), larvae of gall flies (Cecidomyiidae), plant bugs (Miridae), stink bugs (Pentatomidae), aphids, spittlebugs, leafhoppers (Cicadellidae), armored scales (Diaspididae), larvae of sawflies (Tenthredinidae), larvae of tiger moths (Arctiidae), larvae of Geometer moths, larvae of leaf blotch miner moths (Gracillariidae), larvae of slug caterpillar moths (Limacodidae), larvae of Lyonet moths, larvae of owlet moths (Noctuidae), larvae of prominent moths (Notodontidae), larvae of giant silk moths (Saturniidae), larvae of Sphinx moths, thrips, larvae of hairstreak butterflies (Satyrium spp.), and larvae of the Viceroy butterfly (Limenitis archippus) and other brush-footed butterflies (Nymphalidae). The Insect Table provides more information about these species. Various bird species use the Pussy Willow and other willows as a source of food, nesting sites, and/or protective cover. Examples of such birds are the Wood Duck, Northern Pintail, Mallard, Common Redpoll, Evening Grosbeak, Pine Grosbeak, American Goldfinch, Common Grackle, and Ruffed Grouse. The Bird Table provides more specific information about these species. Because willows attract a large number of insects, they provide excellent foraging sites for various insectivorous birds. Mammals also use these shrubs and trees as sources of food. This includes the American Moose and White-tailed Deer (twigs, foliage), American Beaver (bark, wood), Muskrat and Cottontail Rabbit (bark), as well as the American Black Bear, Fox Squirrel, Meadow Vole, and Prairie Vole (leaves, buds, and/or catkins); see Martin et al. (1951/1951), Hamerstrom & Blake (1939), and Romain et al. (2013). Even turtles, such as the Snapping Turtle and Wood Turtle, feed on the fallen leaves (Ernst et al., 1994; Lagler, 1943). Beavers often use the branches of willows to construct their lodges and dams.
Photographic Location: A wet sand prairie at the Iroquois County Conservation Area in NE Illinois. The photographed shrub has an unusually hairy stem.
Comments: This shrub should not be confused with the non-native Salix caprea (Goat Willow). This latter species is often cultivated and it is also called 'Pussy Willow.' The Goat Willow has even larger male catkins than the native Pussy Willow, but it rarely escapes into the wild. While it is rather variable across its range, the native Pussy Willow can be distinguished from other similar willows by its leaves: 1) they are more wide than the leaves of some willow species, 2) their margins are irregularly crenate-serrate to nearly smooth, rather than finely serrated or entirely smooth, 3) its leaf undersides are hairless, glaucous, and whitened, and 4) the large stipules at the base of the leaf petioles are about as wide as they are across and they are often persistent. Because the young stems of Pussy Willow can be hairless, slightly pubescent, or even densely pubescent, their level of hairiness is unreliable in making an accurate identification. The leaves of Salix glaucophylloides (Blue-Leaved Willow) are rather similar to those of Pussy Willow, however Blue-Leaved Willow has leaves with finely serrated margins.