8th Jan 2005
Rhubarb is certainly one vegetable that has managed to totally confuse me over the years; it's classified as a vegetable in all gardening books and show schedules, but always eaten as a fruit. Indeed a vast number of cultivars that we routinely classify as vegetables are in fact botanically classified as fruits. Any vegetable that develops from the flower is a fruit, a good example being peas and beans whilst all the peppers, chilis and Aubergines also fall into the Botanical classification of fruit yet are eaten and exhibited as vegetables.
The Rhubarb, probably as old as any of our vegetables, dating back to over 2000 BC really deserves a far better position in our vegetable garden. Being a perennial, it will grow in the same position for many years, totally unattended, which is probably one reason why it's inevitably planted in some 'out of the way' location which hardly helps it to produce the best crop. In this country we always eat the stalks, stems, sticks or petioles (which are the correct term to call them) and to get the best quality, a little bit of thought needs to go to its growing location. Fortunately it will grow in most soils provided that the location is not prone to prolonged water logging in winter which could cause the crown to rot. It will repay you well if you choose a sunny position and thoroughly and deeply dig over the location; at least two spade depths deep, incorporating plenty of well rotated manure in the process.
Seed or Established Roots?
You can grow Rhubarb from seed but it is better, and much quicker, to obtain established roots. You can do this by purchasing them from seed catalogues or even from a friend who has a healthy, strong plant with well coloured stems. In fact you could be doing your friend a favour by getting him to lift up a root and dividing it.
Lifting and Dividing
Rhubarb, in order to continue to supply you with top quality stems, needs to be lifted and divided up, any time after it"s been growing in the same location for over five years. I well remember carrying out this task many years ago in my first garden and I couldn't believe the size of the roots that came up, they were long and thick and only the spade could eventually cut through them. When dividing the clump, the best and productive material will be around its outer edges; these can be chopped off with the spade making sure that each piece will have at least one shoot or crown as part of it. The black central dead material can then be disposed of.
In theory, rhubarb can be planted at any time of the year but it's preferable to carry out the task during the autumn or early spring. Plant the new divisions with the crowns about two inches below soil level and water them in, should the weather be dry at the time. During the first season the young plant will produce just a few stalks and these must be left to grow on otherwise the plant will be seriously weakened. During the second season you can pick over each plant two or three times thereafter you can pick normally. Should the plant throw up a flower head they have to be removed, don't try pulling or tearing it away, this is best done by cutting the flower stalk as close to the crown as possible. The flower stalks tend to appear from late May to early June onwards, weakening the plant at a time when it should be conserving it's energies after the picking season.
Naturally grown, Rhubarb is a spring and early summer crop, but it can be forced so that it's ready to eat at least two weeks earlier when the stems will be tender and absolutely delicious. You can do this now, cover over a few clumps with some straw, or alternatively, cover each clump with a large plastic pot, half casks or a wooden box. For the best stems, the pots will then need covering over with manure or straw to generate extra warmth.
At this time of year the Rhubarb clumps will be dormant, don't however think that because there is nothing to be seen, nothing needs to be done. An application of well rotted manure now, forked into the soil as well as applied as a covering over the clumps, when there is no frost forecast, will definitely reward you in the spring with strong powerful stems. If you really do want the best out of you clumps then feed the plants once or twice with a balanced liquid fertiliser during the growing season making sure that it's well soaked into the ground.
Rhubarb is easy to grow and is relatively free from pests with the only common disease generally being Crown Rot. This is a fungal infection which causes the terminal bud to rot as well as the tissues below ground. There is no cure for Crown Rot and the whole clump has to be dug up and burnt or placed in a polythene bag and disposed of at your local tip. Always grow new stock plants in a different area of your garden.