Swamp Dewberry
Rubus hispidus
Rose family (Rosaceae)

Description: This is a branching woody vine with trailing stems up to 8' long. The stems are light green to red, angular or terete, and sparsely to moderately covered with bristly hairs. In addition, sometimes softer hairs and widely scattered small prickles are present along the stems. Alternate trifoliate leaves occur along these stems on long petioles up to 4" long. On rare occasions, some leaves may have 5 leaflets, instead of the usual 3 leaflets. Individual leaflets are 1-2" long and about one-half as much across; they are ovate to obovate and coarsely toothed along their middle to upper margins. The upper leaflet surface is medium green, hairless, and somewhat shiny, while the lower surface is more pale and sometimes softly hairy. The terminal leaflet of each trifoliate leaf has a short petiolule (basal stalklet) about 1/8" long, while the lateral leaflets are sessile.

Occasionally, small cymes of 3-6 flowers are produced from axils of the leaves on peduncles up to 6" long. The peduncles are light green to reddish green and sparsely to moderately covered with small bristles or hairs. Each flower is -" across, consisting of 5 white petals, 5 light green sepals that are united at the base, a ring of numerous stamens, and a compound pistil at its center that is light green. The petals are oblong-elliptic in shape, while the sepals are ovate and softly hairy. The blooming period occurs during early to mid-summer for about 3 weeks. Fertile flowers are replaced by compound drupes that are -" in length at maturity. Immature drupes are light green or white, becoming red during an intermediate stage, and finally dark purple or black when they are ripe. Each drupe consists of a cluster of small drupelets; each fleshy druplet contains a single seed. Usually, the flavor of mature drupes is sour. The root system is woody and branching. Sometimes the tips of trailing stems develop rootlets on moist ground, enabling this vine to spread vegetatively. The leaves are semi-evergreen and often become reddish during the fall or winter.

Cultivation: The preference is dappled sunlight, wet to moist conditions, and an acidic soil containing sand or peat.

Range & Habitat: The native Swamp Dewberry is occasional in northeast Illinois and either rare or absent elsewhere in the state. Habitats include swamps, moist sandy woodlands, moist sandy thickets, moist sand prairies and sandy shrub prairies, edges of marshes, and bogs. This vine is found in both degraded and higher quality habitats, favoring areas that have been burned over by fire during periods of drought.

Faunal Associations: The flowers of Swamp Dewberry are visited primarily by bees, including both long-tongued and short-tongued bees. Other insects that may visit the flowers include Syrphid flies, bee flies, small butterflies, and skippers. Both nectar and pollen are available as floral rewards to such visitors. The remaining information about floral-faunal relationship applies primarily to Rubus spp. in general, which consist of blackberries, raspberries, and dewberries. Many insects feed on the leaves, stems, fruit, plant juices, and other parts of these woody plants. These species include leaf beetles, aphids, leafhoppers, treehoppers, the larvae of sawflies, and the caterpillars of many moths. Both the Insect Table and the Moth Table list many of these species. Vertebrate animals also use Rubus spp. as sources of food, particularly their fruits. The fruits of dewberries are sometimes eaten by turtles, including Clemmys insculpta (Wood Turtle), Terrapene carolina (Eastern Box Turtle), Terrapene ornata (Ornate Box Turtle), and Kinosternum subrubrum (Eastern Mud Turtle). Many mammals also feed on the fruits of dewberries and other Rubus spp., including the Black Bear, Gray Fox, Red Fox, Raccoon, Opossum, Eastern Chipmunk, Red Squirrel, Gray Squirrel, Fox Squirrel, White-Footed Mouse, and Woodland Deer Mouse. In wetland areas, muskrats feed on the roots to a minor extent, while White-Tailed Deer and the Cottontail Rabbit feed on the foliage and woody stems in a wider range of habitats. The fruits of Rubus spp. are also eaten by upland gamebirds and many songbirds (see Bird Table). These various animals help to disperse seeds of the fruits into new areas.

Photographic Location: A sandy swamp at the Indiana Dunes State Park in NW Indiana.

While most blackberries and raspberries produce arching canes up to 6' high, dewberries produce trailing stems that creep along the ground. Compared to the upland species, Rubus frondosus (Common Dewberry), Swamp Dewberry has leaflets with tips that are more blunt and its stems are bristly, rather than prickly. The flowers of Swamp Dewberry are also smaller in size (-" in across) than those of Common Dewberry (-1" across). Another species, Rubus pubescens (Dwarf Raspberry), also produces trailing stems like a dewberry and it is found in habitats that are similar to those of Swamp Raspberry. Dwarf Raspberry usually has leaflets with more pointed tips than those of Swamp Dewberry, and its stems have soft hairs, rather than sharp bristles or prickles. Dwarf Raspberry usually produces its flowers individually, rather than in small corymbs, and its mature fruits are red, rather than dark purple or black. Another dewberry, Rubus trivialis (Southern Dewberry), occurs in southern Illinois. This latter species differs from Swamp Dewberry by having stems with both prickles and gland-tipped hairs. Its non-flowering stems produce leaves with 5 leaflets, rather than 3 leaflets, and its flowers are produced individually, rather than in small corymbs.