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:

General Information

Rubus trifidus is an evergreen shrub producing a cluster of erect, unarmed, stems up to 200cm tall[, ]. The stems only produce leaves in their first year, producing flower and fruit-bearing branches in their second year of growth
The plant is harvested from the wild for local use as a food. It is often cultivated as a fruit crop in Japan, especially in regions close to the sea[, ]. It is sometimes grown as an ornamental.

Known Hazards

None known

Botanical References

, ,

Range

E. Asia - central Japan.

Habitat

Near sea shores in the warmer areas of C. Japan[].

Properties

Edibility Rating
Habit	Evergreen Shrub
Height	2.00 m
Pollinators	Insects
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Rubus trifidus is native to the temperate regions of central Japan, where winters are generally mild. Plants often do not flower very freely outside the plant's native range[].
Easily grown in a good well-drained loamy soil in sun or semi-shade[, , ].
Plants are evergreen when grown in a sheltered woodland[].
Plants have perennial stems that are thornless[].
Plants in this genus are notably susceptible to honey fungus[].

Edible Uses

Fruit - raw or cooked[, , , ]. A grateful taste[]. A globose, yelow or red, raspberry-like fruit[, ].

Medicinal

None known

Other Uses

None known

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[].