Common Blackberry
Rubus allegheniensis
Rose family (Rosaceae)

Description: This native woody shrub forms canes that are initially erect, but often bend downward to re-root in the ground. These canes actively grow and form leaves during the first year, and develop fruits in the form of drupes during the second year, afterwhich they die down. The canes are about 3-6' tall; they are green where there is new growth at the tips, otherwise they are brown or reddish brown with stout prickles that are straight or somewhat curved. The alternate leaves are usually trifoliate or palmately compound; they have long petioles. The leaflets are up to 4" long and 3" across; they are up to twice as long as wide. A typical leaflet is usually ovate with coarse, doubly serrate margins; it may have a few scattered white hairs on the upper surface, while the lower surface is light green and pubescent. 

The canes develop racemes with about 12 white flowers; these racemes are much longer than they are wide. There are conspicuous glandular-tipped hairs on the peduncles and pedicels of the inflorescence. A flower has 5 white petals and 5 green sepals with pointed tips; this flower is about -1" across. The petals are longer than the sepals, rather rounded, and often wrinkly. In the center of each flower, are numerous stamens with yellow anthers surrounding a green reproductive structure with a prickly appearance. The flowers bloom during late spring or early summer for a month; there is little or no floral fragrance. The drupes develop later in the summer; they are about " long and 1/3" across, although their size varies with moisture levels. The drupes are initially white or green, but eventually turn red, finally becoming almost black. They are seedy and have a sweet flavor when fully ripened. The root system consists of a taproot. This plant often forms loose colonies vegetatively.

Cultivation: The preference is light shade to full sun, and mesic conditions; some drought is tolerated, although this can reduce the size of the drupes. Growth is best in rich fertile soil; a clay-loam or rocky soil is also acceptable. This plant is easy to grow from transplants or cuttings of young growth. It can become aggressive and be difficult to eliminate; the use of herbicides may be required on some occasions.

Range & Habitat: Common Blackberry occurs in most counties of Illinois; it is common in most areas of central and northern Illinois, and somewhat less common in southern Illinois (see Distribution Map). Habitats include moist to slightly dry prairie edges along woodlands, thickets, open woodlands, savannas, woodland meadows, limestone glades, fence rows, areas along roadsides and railroads, and abandoned pastures. This plant favors disturbed, burned-over areas in and around woodlands; it is one of the shrubby invaders of prairies.

Faunal Associations: The nectar and pollen of the flowers attract many kinds of insects, especially long-tongued and short-tongued bees. This includes honeybees, bumblebees, Little Carpenter bees, Nomadine Cuckoo bees, Mason bees, Green Metallic bees and other Halictid bees, and Andrenid bees. Other visitors of the flowers include wasps, flies, small to medium-sized butterflies, skippers, and beetles. Many of the flies and beetles feed on pollen and are not very effective at pollination. The caterpillars of the butterfly Satyrium liparops strigosum (Striped Hairstreak) and several species of moths feed on the Common Blackberry (see Moth Table). Also, various upland gamebirds, songbirds, and mammals feed on the fruit, stems, or foliage of this plant (see Wildlife Table). Among the upland gamebirds, the Greater Prairie Chicken, Wild Turkey, Bobwhite, and Ring-Necked Pheasant have been observed eating the drupes of blackberries. These various animals help to distribute the seeds far and wide. The Common Blackberry provides some shelter and shrubby protection to various ground-nesting birds and small mammals, such as the Cottontail Rabbit. In general, the ecological value of blackberries is very high.

Photographic Location: The photographs were taken at Meadowbrook Park in Urbana, Illinois.

Comments: Occasionally, blackberries (Rubus spp.) are found along the edges of prairies. It can be difficult to tell the different species apart. This is one of the more common blackberries in Illinois. The fruits of Common Blackberry tend to be a bit larger and more elongated than those of other blackberries, and they usually have an excellent flavor. This blackberry is distinguished from other blackberries by the numerous glandular hairs on the peduncles and pedicels of its elongated racemes of flowers. Furthermore, its mature leaflets are usually no more than twice as long as they are wide. These two characteristics distinguish the Common Blackberry from other Rubus spp. in Illinois.

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