Rubus allegheniensis aka Allegheny Blackberry

Rubus allegheniensis is also called Allegheny blackberry. It belongs to the rose family. This shrub sheds its leaves each year. It comes from eastern Canada and the United States. Its native range extends west to Nebraska, Kansas, and Oklahoma. It grows in woods, clearings, and dry thickets. It also grows on grassy mountain sites. Plants in California and British Columbia likely escaped from gardens. Garden plants reach about 5 feet [1.52 metres] tall. Some reach 8 feet [2.44 metres], with a similar spread.

The plant forms thickets of canes that start upright. These canes later bend into arches. Its roots live for years, but each cane lasts two. New canes grow leaves in their first year. They bear fruit the next year, then die. Young tips are green. Older stems turn reddish brown or purple-red. Thick prickles cover the canes. The branches have hairs with glands at their tips. Leaves grow in turn along the stems, not in pairs. Each has three to seven leaflets, often five. Each leaflet has coarse teeth along its edge. Its underside is paler and hairy. Fall leaves may turn red, orange, or purple.

White flowers open from May to June. They form loose racemes, or flower clusters, at stem tips. Each flower has five petals and little or no scent. Bees and butterflies come for nectar and pollen. Fruit ripens in summer. Reports from North Carolina note ripe fruit in July. Each blackberry joins many small drupes, each with a seed. Fruit starts green or white, turns red, then black. Picked berries keep their central core, unlike raspberries. Ripe fruit tastes sweet but has many seeds. Eat it fresh, cooked, dried, frozen, or in preserves. PFAF also lists peeled spring shoots as safe to eat.

Grow this blackberry in sun or light shade, not heavy shade. It grows well in rich loam that drains well. It also tolerates clay loam and rocky ground. NC State lists acidic soil and USDA zones 3–8. The plant can cope with drought and needs little routine care. It grows fast and spreads to form colonies. These traits suit food gardens and meadows. They also suit sites where plants can spread and grow freely. Dense growth with prickles can form a barrier.

Birds and mammals eat the fruit and find shelter among canes. Some bees nest inside dead stems. Deer and rabbits eat leaves, though deer cause moderate damage. Prickles and strong spread can make the plant hard to remove. NC State lists cane borers as a possible pest. It also lists Fusarium wilt as a possible disease. It reports no major problems overall. PFAF records no known hazards and notes dyes made from fruit. It also lists past uses of the plant as medicine. Those uses do not prove that it works as a treatment.