Rhubarb

Profile

Family

Polygonaceae

Habit

perennial

Height

1.5 m

Spread

2 m

Growth

very fast

Lifespan

15 years

First yield

after 3 years

Hardiness

zone 3–9

Shade tolerance

partial shade

Soil

Silt, Loam, Clay

Soil moisture

semi-dry – very moist

pH

5.9 – 8.1

Synonyms

R. undulatum. L.

Uses

Edible: Leaf stalk – raw or cooked. It tastes sour and is used in spring as a fruit substitute, usually boiled with sugar and made into cakes, jams etc. The juice of cooked rhubarb gives fruit punch colour and flavour. Because of the oxalic acid content, the stalks should not be consumed in large quantities – see the toxicity notes above. Unripe flowers – cooked and used like cauliflower. According to one report the plant contains 0.7% rutin. The plant part is not specified, but it is most likely the leaves.

Other uses: The leaves can be simmered in hot water to produce an insecticide.

Growing

Rhubarb is a very easy-care and undemanding plant that even tolerates neglect. It prefers deep, fertile, moderately heavy, humus-rich, moisture-retaining and well-drained soils in sunny or semi-shaded positions. It thrives in most soils provided drainage is good, and also grows in the dappled shade of trees, as long as there is enough side light. It grows well in heavy clay soils. It tolerates acid soils, but prefers a pH between 6.5 and 7. The plants are very hardy and tolerate temperatures down to at least -20°C. Hot summers, however, are not to its liking, and it can die out in warmer climate zones. Rhubarb is a long-lived and almost indestructible perennial. It is often grown for its edible leaf stalks; there are many cultivars. Most cultivars produce edible stalks from spring to early summer, with the cultivar 'Glaskin's Perpetual' being harvestable throughout the summer. By lifting the roots in autumn and exposing them to frost, earlier growth is encouraged. These roots can then be transplanted into a cold frame or other sheltered area where they form their edible stalks in late winter. Earlier outdoor harvests can also be achieved by covering the plants with a layer of straw and an upturned bucket. This species is probably a hybrid (R. rhaponticum x R. palmatum). It hybridises readily with other species of the genus. Plants of this genus appear to be immune to rabbit browsing.

Propagation

Sowing – best in autumn in a shady cold frame. Sowing can also be done in spring in a cold frame. As soon as the seedlings are large enough, prick them out into individual pots and overwinter them in a greenhouse or cold frame. They can be planted out in spring. This species is a hybrid and does not necessarily come true from seed. However, sowing offers the opportunity to select particularly attractive plants among the seedlings. Division in early spring or autumn. Divide the rootstock with a sharp spade or knife and make sure that each division has at least one bud. Larger divisions can be planted directly at their final position. Smaller divisions should be potted up before planting out and grown on in a semi-shaded cold frame until well established. They can then be planted out in late spring or early summer.

Origin & habitat

E. Asia - Siberia.

Steppe, open woodlands and sandy soils.

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