Stone Bramble

• Growing form

  Perennial herb. Stems biennial, dies after flowering. Rhizomatous.

• Height

  10–35 cm (4–14 in.). Runners up to several metres long. Stem rough, with sparse, delicate spines.

• Flower

  Corolla regular (actinomorphic), whitish, 3–5 cm (1.2–2 in.) long; petals usually 5, narrow, 3–5 mm (0.12–0.2 in.) long. Sepals 5. Stamens many. Gynoecium separate, pistils several. Inflorescence a 3–15-flowered corymb.

• Leaves

  Alternate, stalked, stipulate. Blade palmate, with 3 leaflets. Leaflets ovate–elliptic, terminal leaflet stalked, lateral leaflets unsymmetrical, all leaflets with doubly serrated margins.

• Fruit

  Bright red, shiny, quite acidic aggregate of drupes.

• Habitat

  Broad-leaved forests, young forest heaths, ridges, rocky and stony ridged forests, meadows, banks.

• Flowering time

  June.

Stone bramble’s relatives include many respected and financially important berry plants. Even though its berries are juicy and taste good, it often produces such a poor crop that they are hardly worth picking. Forest mammals and birds eat the fruit and spread the seeds, but sexual reproduction is rare. Stone bramble spreads very efficiently, however: rooting runners grow from the base and can snag passers-by. A single runner can grow up to 3.5 metres (140 in.) in a summer, and the combined length of a plant’s runners can be as much as 40 metres (135 feet). Runners root at the end of the summer and the new plants become independent when the connection to the mother plant is severed. Stone bramble thrives in many kinds of damp and at least moderately rich forests as its long runners can bypass any small, unfavourable areas. Stone bramble exploits human activity as thinning and clear-felling in the forest creates more light, allowing the stands to become denser and wider, and the plants can produce more fruit.

Stone bramble cross-breeds with its close relative arctic bramble (R. arcticus). The hybrid is quite like arctic bramble but it grows more exuberantly and flowers more brilliantly – albeit without any berries. From stone bramble it inherits a tendency to produce runners and it can produce large stands in this manner.

Rubus humulifolius

Rubus humulifolius

Finland’s wild flora includes (or included) another stone bramble species, Rubus humulifolius, a low-growing plant that resembles stone bramble. On closer inspection, however, its leaves do not have 3-5 lobed leaflets like stone bramble, but are rather like hop leaves, and it also lacks stone bramble’s characteristic runners. The species’ only known Finnish habitat in Jyväskylä was destroyed by construction in 1957, but the plant was saved for cultivation. Attempts have been made to return R. humulifolius to the wild, close to its original habitat, but with limited success. Luckily, however, it is being preserved in a botanic garden.