Description: This native perennial shrub is 2-5' tall, forming arching woody canes. First-year canes produce leaves that are palmately compound (usually 5 leaflets), while second-year canes produce trifoliate leaves (3 leaflets). First-year canes are infertile, while second-year canes bear flowers and fruit. The latter die down after bearing fruit, but they often start new canes vegetatively when their tips touch the ground. Young canes are light green, stout, and rather angular, but they later become red, reddish brown, or black. Stout prickles occur along the sides of the canes; these prickles are usually curved, rather than straight.
The compound leaves of first-year canes
span up to 6" long and 6" across (excluding their petioles). The terminal
leaflet is larger than the lateral leaflets; it is up to 3" long and 2½"
across (less than twice as long as its width). Each terminal leaflet is ovate
to oval in shape, rounded or cordate at the base, and coarsely serrated along
its margins; the lateral leaflets are similar, except they are more slender in
shape. At the base of each terminal leaflet, there is a conspicuous stalk about
½" long, while the lateral leaflets are sessile, or nearly so. On the
upper surface, each leaflet is medium green and either hairless or sparsely
hairy; on the lower surface, each leaflet is light green and finely pubescent,
especially along the veins. The petioles of the compound leaves are up to 4"
long, pale green, and either hairless or sparsely pubescent; there are often
1-2 tiny curved prickles along the length of each petiole. The leaflets of
second-year canes are slightly smaller in size than those of the first-year
canes, and their terminal leaflets are more slender than the terminal leaflets
of the latter. Otherwise, the leaflets of both types of canes are very similar
to each other. Second-year canes bear short corymbs of flowers spanning about
2-4" across. Each flower is about 1" across, consisting of 5 white petals, 5
light green sepals, a cluster of light green pistils, and numerous
stamens. The petals are
oblanceolate in shape and rather wrinkled in appearance; they are much longer
than the slightly pubescent sepals. At the base of the pedicel of each flower,
there is usually a leafy bract of varying size; the flowers are often nearly
hidden by these bracts. The blooming period of this blackberry occurs during
late spring to early summer. Each flower is replaced by a juicy fruit (compound
drupe) that is globoid-ovoid in shape and up to ¾" long. The fruit
becomes black at maturity; it has a pleasant sweet-tart flavor, sometimes with
a slightly bitter aftertaste. Each drupelet within the fruit contains a single
seed. The root system is woody and branching. Loose colonies of plants are
often formed from vegetative propagation of the canes.
Cultivation: The preference is full or partial sun,
moist to dry-mesic conditions, and soil containing loam, clay-loam, or some
rocky material. The size of the fruit is strongly influenced by the amount of
precipitation during the first half of summer.
Range & Habitat: Leafy-Flowered Blackberry is
fairly common and it can be found throughout Illinois (see
Distribution
Map). Habitats include woodland openings, woodland edges, savannas,
thickets, weedy meadows, and fence rows. This shrub is typically found in areas
with a history of disturbance, although it is intolerant of regular
mowing.
Faunal Associations: This
species and other blackberries (Rubus spp.) are important to many kinds
of wildlife. The nectar and pollen of the flowers attract many kinds of
insects, including long-tongued and short-tongued bees, wasps, bee flies,
butterflies, and skippers. The larvae of many moths feed on the leaves and
flowers, or bore through the canes (see
Moth Table). Other insects
that feed on various parts of blackberries include several leaf beetles, larvae
of long-horned beetles, stinkbugs, aphids, sawfly larvae, and others (see
Insect Table). The fruit is
an important source of food to many songbirds and upland gamebirds (see
Bird Table). Many mammals feed
on the fruit of blackberries as well, including the Deer Mouse, White-Footed
Mouse, Jumping Mouse, Eastern Chipmunk, Fox Squirrel, Gray Squirrel, Red
Squirrel, Red Fox, Raccoon, Striped Skunk, and Black Bear. White-Tailed Deer
and Cottontail Rabbits feed on the leaves and twigs. The prickly canes and
leaves of blackberries also provide protective cover for small mammals and
birds.
Photographic Location: A
grassy meadow near Urbana, Illinois.
Comments: The different species of blackberry (Rubus spp.) can be difficult to identify and different authorities don't always agree on their taxonomic classification. Leafy-Flowered Blackberry is very similar in appearance to Rubus pensilvanicus (Pennsylvania Blackberry) and some authorities consider them to be variants of the same species. For Leafy-Flowered Blackberry, the terminal leaflets of sterile canes are usually cordate (indented) at the base, while the terminal leaflets of Pennsylvania Blackberry are rounded at the base. Furthermore, the floral bracts of Leafy-Flowered Blackberry are all leafy, while the floral bracts of Pennsylvania Blackberry are a mixture of leafy and stipule-like bracts. However, in the field, some shrubs display mixed characteristics. These two species of blackberries differ from other blackberries in one or more of the following features: 1) their terminal leaflets are no more than twice as long as they are across, 2) they usually lack glandular hairs, 3) their corymbs of flowers are short and often partly hidden by the leafy bracts, and 4) at least some of their floral bracts are large and leafy, rather than small and stipule-like.