The genus Rubus, (especially the blackberries, which are often loosely referred to as Rubus fruticosus agg.) presents some of the most difficult taxonomic problems. This is partly due to the frequency of polyploidy; also to the frequent occurrence of hybridization; and also due to apomixis, where minor differences between plants are preserved because seedlings are genetically identical to their parent. As a result, differences of opinion on the number of species to be recognized from a given region can vary tremendously (for example, a treatment by M. L. Fernald[] in 1950 recognized 205 species for the northern half of the eastern United States plus parts of southeastern Canada, whilst H. A. Gleason and A. Cronquist in 1991 recognized only 25)[]. Where possible, a relatively conservative approach is taken here[].

Common Name: American Dewberry

General Information

Rubus canadensis is a deciduous shrub producing a cluster of erect to arching, biennial stems from a woody rootstock. The stems can be unarmed or sparsely armed, growing from 50 - 300cm long[, ]. The stems only produce leaves, and do not flower, in their first year of growth; forming flowering branches in their second year and then dying after fruiting. The plant can form extensive thickets, spreading by means of rhizomes and tip layering of the stems[].
The plant is harvested from the wild for local use as a food. Ii is cultivated as a fruit crop in North America, Great Britain and Central Europe[].

Known Hazards

None known

Botanical References

, ,

Range

Eastern N. America - Ontario to Newfoundland, south to Minnesota, Tennessee and Georgia

Habitat

Thickets, woods and clearings[, ]. Mountainous highlands, cool, shaded intermediate regions within deciduous and boreal forests, margins of lakes and woods; at elevations up to 2,000 metres[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Shrub
Height	2.00 m
Pollinators	Apomictic
Cultivation Status	Cultivated, Wild

Cultivation Details

Easily grown in a good well-drained loamy soil in sun or semi-shade[, , ]. Dislikes shady sites[].
The stems are free from prickles[].
The plant produces apomictic flowers, these produce fruit and viable seed without fertilization, each seedling is a genetic copy of the parent[].
The plant is very resistant to fire - top growth is killed, but the plant resprouts vigorously from the roots[].
Plants in this genus are notably susceptible to honey fungus[].
Rubus canadensis has a wide range and is the most northerly of all the highbush blackberries. The species is morphologically similar to Rubus allegheniensis except that the plants have little armature, are not as hairy, and have no glands. It also has characteristically lustrous leaves. The open and edge habitats in which it grows can greatly influence the phenotype, as with most highbush blackberries. At higher elevations or in poorer soil conditions, the plants are smaller; when partially shaded, leaves of primocanes may be larger. Leaves of floricanes vary in size and shape and are unreliable for identification[].

Edible Uses

Fruit - raw or cooked in pies, jams etc[, , , , ]. Sweet, juicy and richly flavoured, it is generally preferred to most other species of blackberries[, ]. The fruit can be pressed into cakes and then dried for later use[]. The black, globose fruit can be up to 25mm long[].

Medicinal

The stems and the fruit have been used in the treatment of dysentery[].

A decoction of the root has been used in the treatment of dysentery[].

Agroforestry Uses:

The plant has good erosion control value. It grows satisfactorily on barren and infertile soils and invades and occupies eroded areas. It also establishes quickly on burns, old fields, and logged areas. Forming extensive and nearly impenetrable thickets, it provides excellent cover for wildlife and nesting sites for small birds. It is a natural pioneer species, paving the way for woodlands to develop, but should only really be used within their native range to avoid risks of the plant invading other habitats[, ].

Other Uses

This species is involved in the origin of numerous blackberry cultivars. It is considered valuable in breeding programmes especially for its high tolerance to frost[].

A purple to dull blue dye is obtained from the fruit[].

Propagation

Seed - requires stratification and is best sown in early autumn in a cold frame. Stored seed requires one month stratification at about 3°c and is best sown as early as possible in the year. Prick out the seedlings when they are large enough to handle and grow on in a cold frame. Plant them out into their permanent positions in late spring of the following year.
Cuttings of half-ripe wood, mid summer in a frame[].
Tip layering in July. Plant out in autumn.
Division in early spring or just before leaf-fall in the autumn[].