Rubus suavissimus Seeds | Chinese Blackberry

Sweet tea berry shrub with white flowers and red aggregate fruit on arching canes — Sweet Tea Berry (*Rubus suavissimus*): Rosaceae, mountains of Guangxi in southern China.

LATIN NAME: Rubus suavissimus

COMMON NAME: Chinese Blackberry

Plant Profile

Sweet tea berry is a deciduous shrub of the rose family from the mountains of Guangxi in southern China, grown for leaves that taste sweet without sugar. It reaches one to two metres, with arching, reddish-brown canes armed with small prickles, three- to five-lobed leaves and white, five-petalled flowers in spring. Small red aggregate fruits follow in summer, edible but insipid. The leaves are the crop: dried and brewed, they give a pale, sweet infusion used in the region for centuries and now sold as a natural sweetener. The plant grows on forest margins and roadsides in the Dayao Mountains, in acid soil and humid air, and it spreads by suckering into loose thickets. It is one of the few sweet-tasting members of a genus better known for raspberries.

Science & Biotechnology

The sweetness comes from rubusoside, a diterpene glycoside that is roughly sixty times sweeter than sucrose and that survives drying and boiling, which makes it unusual among plant sweeteners. The leaves also contain steviol-related compounds in small amounts, and the combination gives the infusion a sweetness that arrives slowly and lingers. Rubusoside is now produced commercially by enzymatic conversion and used to mask bitterness in beverages, and it has been studied for its ability to solubilise other compounds. The species is closely related to Rubus chingii, and some taxonomists treat it as a variety, which matters because the two are sold for different purposes: one as a sweetener, the other as a tonic fruit. Cytological work shows a higher chromosome number than the diploid raspberries, suggesting a polyploid origin.

Uses & Benefits

The dried leaf is brewed as sweet tea and used as a sugar substitute in Guangxi and Guangdong, often blended with other herbs to soften the aftertaste. The fruit is eaten fresh and made into jam, though it is not the reason for growing the plant. In the garden the shrub is ornamental in its own right, with white flowers in spring, red fruit in summer and reddish canes in winter, and it is a good choice for a wildlife hedge. It is also used in China as a ground cover on acid slopes, since it suckers freely and holds soil. The leaves can be picked from the second year without harming the plant, and a single bush supplies a household.

Growing from Seed

Sow the seed in autumn, either fresh or after three months of cold stratification in damp sand. Surface-sow on a mix of leaf mould, sand and compost, cover with three millimetres of grit, and keep at eighteen to twenty degrees. Germination is slow and uneven, sometimes taking three months. The seedlings are small in their first year; grow them on in half shade with steady moisture. Plant out in autumn or early spring into acid, humus-rich soil in sun or half shade. Water through the first summer, mulch with leaf mould, and cut out old canes at the base each winter to keep the bush productive and the leaves easy to pick.

Our Take

A rose-family shrub whose leaves sweeten tea without sugar. It fruits, it flowers, and it earns its space twice over.

Herb Seeds