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[
Rubus calycinoides Hayata ex Koidz.
Rubus elmeri Focke
Rubus hayatae-koidzumii Naruh.
Rubus pentalobus Hayata
Rubus rolfei is an evergreen perennial plant with more or less woody, creeping stems that root at the nodes, sending up erect fruiting stems at intervals. The plant forms a mat of growth up to around 8cm tall[
The fruit is harvested from the wild for local use as a food. The plant is sometimes grown as an ornamental, where it can be used as a ground cover.
E. Asia - Taiwan, Philippines
Open places, mixed forests at elevations of 1,300 - 3,800 metres in Taiwan[
]. Forest and more open places like clearings at elevations of 900 - 2,700 metres in the Philippines[
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Rubus rolfei is native to higher elevations in the subtropical and tropical zones of Taiwan and the Philippines. It has proved to be hardy in the milder regions of the temperate zone[
Easily grown in a good well-drained loamy soil in sun or semi-shade[
]. Succeeds in deep shade.
Plants are evergreen in most climates but they can lose their leaves in severe winters.
Occasionally cultivated for its edible fruit, there are some named varieties[
]. 'Emerald Carpet' is an ornamental thornless form with orange berries that resemble small raspberries[
Plants in this genus are notably susceptible to honey fungus[
Fruit - raw or cooked[
]. Fleshy, with a sweet flavour[
]. The orange-yellow fruits are well-flavoured[
]. The yellow to orange or reddish, globose fruit is up to 14mm in diameter with a reddish persistent calyx[
A good ground cover plant for a sunny position or deep shade[
]. It makes a firmly matted cover though it requires weeding for the first year or so[
]. Plants are best spaced about 60cm apart each way[
A purple to dull blue dye is obtained from the fruit[
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[
Division in early spring or just before leaf-fall in the autumn[