Allegheny Blackberry, Rubus  allegheniensis

Allegheny Blackberry

Rubus allegheniensis

Benefits:
Sun Shade:
Bloom Time: Late Spring/Early Summer
Zones: 2, 3, 4, 5
Soil Conditions: Loam
Soil Moisture: Moist
Color: White
Fragrance: No
Height: 6-12 feet
Spacing: 6 feet


Description

Allegheny Blackberry, Rubrus allegheniensis, is a native perennial shrubby plant with stems that are erect to arching, from 2 to 7 feet long with thorns that are large and nearly straight. Arching canes do not usually root at the tips if they touch the ground. Canes live for two years. They are green initially then becoming a dull reddish brown, without any whitish bloom.

The leaves are alternate, 3 - 7 parted, not lobed but with deep teeth, and on long stalks which have a pair of very short stipules at the base. Upper leaves on the fruiting branches will usually have three leaflets with only the terminal leaflet stalked; larger lower leaves will have 5 leaflets and all can be stalked. The terminal leaflet is always larger. The upper surface is medium green, the lower surface much paler due to fine hair. There is glandular hair on the leaf stalks. Fall color can be a brilliant red.

The 5-part showy flowers are large, around 1 inch wide with the wrinkly white petals longer than the yellow-green sepals. Sepals are triangular and have pointed tips. These reflex when the flower opens. Petals have somewhat rounded tips and narrowed bases. The central section of the flower contains numerous yellow-green carpels, each with a style and these are surrounded by the numerous male stamens that have yellow anthers attached to yellow-green filaments. The anthers turn dark with pollen maturity. The flower stalks have glandular hair as do the stalks of the cluster and the calyx lobes.

Fertile flowers produce a conic to thimble shaped edible berry composed of many drupelets, each containing a single seed. The fruits turn from green to red to purple-black when mature. Fruit forms on second year stems. Picked fruit does not separate easily from the torus (the part of the flower around which the fruit forms). Bloom begins in late May and can continue till July.

Allegheny Blackberry grows in rich to poor soils, needing at least partial sun. It will develop good fruit only with lots of sun but does tolerate drier moisture conditions. The root system is a branching taproot and colonies are frequently formed from underground lateral stolons. Patches can become quite large and at Eloise Butler, thinning is practiced to cut down the volume.

Plant Notes and Herbal Uses
  This is among the largest of our Rubus species.
  Thorns are formidable.
Further Information

Wild Ones of the Fox Valley Area
Prairie Nursery
Wisconsin DNR
Wisconsin Native Plant Nurseries