Rhubarb must be one of the easiest vegetables to grow. Being a long-lived perennial plant, it needs little attention and, whether you get round to forcing or not, it offers the first ‘fruit’ of the year. Most people inherit a clump, often tucked away at the bottom of the vegetable plot or beside the compost heap.
With its huge leaves and bright-red leaf stalks, rhubarb also makes a spectacular addition to a herbaceous border. The flowers are stunning, although flowering will weaken the clump. Regular harvesting of the young leaf stalks will keep the clump trim. It is a very easy crop to propagate; just cut off small sections of the clump and replant in the autumn. You can improve the quality of the stalks by blanching, or force it indoors for an earlier crop.
Seakale
This is an unusual perennial vegetable, which grows naturally on sea shores. Grown and forced in much the same way as rhubarb, it is also attractive enough for a place in the ornamental border. Grow it in an open, unshaded spot and well-drained, preferably sandy soil, with plenty of organic matter.
Blanch by placing a forcing pot or a large (30-cm diameter) upturned flower pot over the crown in January to exclude light. Cut the succulent white stems that grow underneath when they are about 10cm long. Stop cutting by May to allow the plants to recover.
Cook seakale lightly, like asparagus, to avoid destroying its subtle flavor. The young flower heads can also be eaten. But cut off any flower heads in the summer if you want to force the plant next year.
In a border you could leave some plants to flower – seakale is related to the ornamental Crambe. Plants are raised from seed or from root cuttings; or as ‘thongs’ from mail-order suppliers. Seed is slow to germinate, so start it off in pots in a cold frame in the spring or autumn. ‘Lily White’ is the variety most often offered as seed.
Calendar
Rhubarb prefers a sunny position and moist but not waterlogged soil.
March
Early rhubarb varieties left uncovered should be ready to pull. In late March feed established clumps with a general fertilizer to increase the size of next year’s crop. Mulch around the clump with well-rotted manure if you did not do this in the autumn.
Rhubarb can also be raised from seed. Germinate the seed in pots at about IOC in March and plant outside when the plants are large enough.
April –May
Harvest the sticks regularly.
June
Boost leaf growth by scattering a handful of a nitrogen fertilizer (e.g. sulphate of ammonia or dried blood).
July
Stop harvesting. Allow the plants to build up their strength for next year.
November
Established clumps should be thinned about every five years. Dig around the crown and trim it back to four or five good buds. You can slice off sections of crown with a sharp spade, each with a couple of buds, to make new plants.
The best time to plant new crowns is November or December, into well-manured ground. The top bud should be just below the surface. You can also plant in the spring. Whenever you plant, do not harvest until the second summer.
December
For an early crop of blanched rhubarb in February, cover the dormant clumps to exclude light. If your budget does not run to a terracotta forcing pot, a large flower pot or an upturned dustbin will be perfectly adequate.
Harvesting
Young stalks are the most tender and tasty. Always pull rather than cut them. The leaves are poisonous and should be cut off, though they can be composted. The reddish leaf stalks contain low levels of these poisons and should not be eaten raw.
