Stone bramble (Rubus saxatilis, L. 1753)

Identity

Stone bramble (Rubus saxatilis L., 1753) is an accepted species of Rubus in the Rosaceae family. Linnaeus described it in Species Plantarum in 1753. Its flowering stems stand only 10–30 cm (4–12 in) tall and carry few prickles, setting it apart from the large, heavily armed brambles of hedgerows. ^{1 2}

Rocky limestone habitats give this plant several of its names. In French, ronce des rochers describes the screes and limestone faces of its upland habitat. The standardized French flora name grélotte des rochers coexists with that everyday name, with neither used exclusively. ^{6 4}

The English name stone bramble points to the same rocky habitat. The less frequent name roebuck berry associates the plant with roe deer, regular visitors to its woodland fruit. ⁸

Recognition

Low perennial subshrubs of Rubus saxatilis bear upright flowering stems 10–30 cm (4–12 in) tall. Creeping runners root where they touch the soil and can extend much farther. Unlike most Rubus, its prickles are fine, sparse or sometimes absent. ^{7 3}

Trifoliate, stalked leaves remain green on both surfaces, without the white felted underside of raspberry leaves. This often rules out raspberry before the prickles need examination. Leaflets have coarse, double teeth, and the central leaflet has its own short stalk. ⁷

Small white flowers, about 5 mm (0.2 in) across, form loose corymbs of 3–10 flowers at the top of the flowering stems. The small aggregate fruit often has only 2–6 large drupelets, red and glossy, far fewer than the dozens in a typical blackberry. ^{7 5}

Useful taxonomy

Historical varieties now treated by Plants of the World Online as synonyms include Rubus saxatilis var. canadensis Michx., Rubus saxatilis var. inermis Wallr., Rubus saxatilis var. spinulosus Wallr., Rubus saxatilis f. multiloba Hiitonen and Rubus saxatilis var. elongatus H.Post. The name Cylactis saxatilis (L.) Á.Löve, using a formerly separate genus, denotes the same species. ¹

André Michaux reused the name Rubus saxatilis in 1803 for a North American plant distinct from Linnaeus’s European species. This illegitimate usage refers to the species now accepted as Rubus pubescens Raf., rather than the stone bramble described here. The full name with its author, Rubus saxatilis L., 1753, avoids that confusion. ^{1 2}

Habitat and range

Greenland and Iceland mark the western end of a Eurosiberian and cold circumboreal range extending across Europe to Siberia, the Russian Far East and the western Himalayas. The plant grows in northern lowlands and, farther south, in mountains, always on base-rich substrates. ^{1 7}

Within mainland France, stone bramble is strictly montane and limestone-loving, occurring in the Alps, Jura, Vosges, Massif Central and Pyrenees. It is absent from the west, where suitable limestone relief meeting its soil requirements is lacking. ⁶

Native British populations occupy base-rich screes, ravines and rocky woods, reaching more than 1,100 m (3,600 ft) above sea level. Conservation status there remains Least Concern, despite local declines linked to habitat destruction, atmospheric nitrogen deposition and browsing by game animals in some regions. ⁵

Life cycle and reproduction

Altitude and latitude shift flowering within the period from May to July. Each flowering stem carries a loose corymb of small white flowers. Fruit follows from late July to September, with drupelets changing from firm red to a brighter shade and becoming distinctly softer at full ripeness. ^{3 7}

Flowering stems are often biennial and die after fruiting. The plant persists and spreads mainly through creeping runners that root on contact with soil to form new clumps, a vegetative process compared with that of raspberry. ³

For cultivation from seed, one month of cold stratification is required before germination. Semi-ripe cuttings are taken in summer, while division is carried out in early spring or just before autumn leaf fall. ³

Uses and risks

Its tart fruit is edible raw or cooked, with a pleasant flavor despite a modest edibility rating of 2 out of 5 from Plants For A Future. Eastern European preparations include kissel, kvass, jam and syrup; its sharper taste than raspberry often suits cooked dishes better than fresh use. ³

Fruit also yields a purple to dull blue dye, a traditional use less often documented elsewhere in Rubus. Leaves rich in astringent tannins have occasional traditional use for dysentery and intestinal disorders, while a root decoction was used for whooping cough. ³

Plants For A Future lists no known hazards for this species, either for humans or domestic animals, distinguishing it from many ornamental Rosaceae. ³

Varieties, look-alikes and related plants

No recognized horticultural cultivars are listed for Rubus saxatilis. Unlike raspberry and blackberry, it has not undergone commercial cultivar selection. Its apparent diversity instead reflects historical varieties now treated as synonyms of the typical species. ¹

Young raspberry or blackberry shoots are the most frequent field look-alikes. Their white felted leaf undersides and sturdy hooked prickles contrast with the green undersides and absent or very fine prickles of stone bramble. ⁷

Woodland strawberry shares trifoliate leaves green on both sides and limestone woodland habitat, but remains entirely herbaceous and creeping, without producing an upright flowering cane or drupelet fruit. Two to six drupelets distinguish stone bramble from the dozens in a typical blackberry, even without examining the leaves. ⁵

Main sources

• Plants of the World Online / Kew, Rubus saxatilis L.
• International Plant Names Index, Rubus saxatilis L.
• Plants For A Future, Rubus saxatilis
• INPN, Rubus saxatilis L. 1753, stone bramble
• Botanical Society of Britain and Ireland, Rubus saxatilis
• Tela Botanica / eFlore BDTFX, Rubus saxatilis
• Info Flora, Rubus saxatilis L.
• Royal Horticultural Society, Rubus saxatilis - stone bramble