Rubus armeniacus

Rubus armeniacus Himalayan Blackberry
Shoot with immature fruit
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
Order:	Rosales
Family:	Rosaceae
Genus:	Rubus
Subgenus:	Rubus
Species:	R. armeniacus
Binomial name
Rubus armeniacus Focke
Synonyms[citation needed]
R. discolor Weihe & Nees nom. illeg. R. procerus auct. non P.J.Muell.

Himalayan Blackberry flower, Bay Area, California. Note spider on bottom petal.

Rubus armeniacus, Armenian Blackberry or Himalayan Blackberry, is a species of Rubus in the blackberry group Rubus subgenus Rubus series Discolores (P.J. Müll.) Focke. It is native to Armenia in southwest Asia, and widely naturalised elsewhere. Both its scientific name and origin have been the subject of much confusion, with much of the literature using one or the other of the two synonyms, and often mistakenly citing its origin as western European.

Description

Rubus armeniacus is a perennial plant which bears biennial stems ("canes") from the perennial root system. In its first year, a new stem grows vigorously to its full length of 4-10 m, trailing along the ground or arching up to 4 m high, stout, up to 2–3 cm diameter at the base, and green, or reddish-tinged above if open to bright sun. The leaves on first year shoots are 7–20 cm long, palmately compound with five leaflets; flowers are not produced on first year shoots. In its second year, the stem does not grow longer, but produces several side shoots, which bear smaller leaves with three leaflets (rarely a single leaflet); the leaflets are oval-acute, dark green above and pale to whitish below, with a toothed margin, and thorns along the midrib on the underside. The flowers are produced in late spring and early summer on panicles of 3–20 together on the tips of the second-year side shoots, each flower 2–2.5 cm diameter with five white or pale pink petals.

The fruit, in botanical terminology, is not a berry, but an aggregate fruit of numerous drupelets, 1.2–2 cm diameter, ripening black or dark purple. Both first and second year shoots are spiny, with short, stout, curved, sharp spines. Mature plants form a tangle of dense arching stems, the branches rooting from the node tip when they reach the ground.

Cultivation

Berry crop

The species was introduced to Europe in 1835, and Australasia and North America in 1885. It was valued for its fruit, similar to that of common blackberries (Rubus fruticosus and allies); but larger and sweeter, making it a more attractive species for both domestic and commercial fruit production. The cultivars "Himalayan Giant" and "Theodore Reimers" are particularly commonly planted.

Invasive species

Himalayan Blackberry was first introduced to America from Europe in the late 1800s as a cultivated crop. Because it is so hard to contain, HBB quickly got out of control, with birds and other animals eating the berries and then spreading the seeds. From this, HBB eventually spread to the Pacific Northwest, where it is now widespread. Rubus armeniacus soon escaped from cultivation and has become an invasive species in most of the temperate world. However, anthropogenic ecological disturbance often underlies damage that Himalayan blackberries appear to cause.^{[citation needed]} In light of this, the species may perform a valuable ecosystem service by mitigating frequent disturbance (i.e. erosion control, deterring humans^{[citation needed]}).