Growing rhubarb

Rhubarb (Rheum rhabarbarum or Rheum x hybridum, as most varieties are known as) is a popular fruit on our allotments though technically it is a vegetable. It is from the Polygonaceae family and is generally the only member of this family which most of us grow as a crop on our allotments. You may possibly have another member of this family growing on your plots, Rumex spp (Docks) which if you look carefully you can see the family resemblance especially when both flower.

Cultivation is fairly simple, usually the fleshy ‘crown’ is planted while dormant in a well manured planting hole. The crown must sit above the soil surface. It does really well if mulched with compost or manure and straw in the autumn. However, I have been asked over and over recently by some allotment holders when they’ve passed by my plot why their rhubarb doesn’t do very well and why my rhubarb grows so well. It was only when I was asked this question by someone with one of the new allotments that I realised what the problem was…..lack of patience.

To have a successful crop of rhubarb you need to be patient. It should not be picked in its first year and only very, very lightly in the second year if at all. You should also stop picking your rhubarb in mid July to allow the plant to recover before it dies down in the autumn, much like asparagus. The other reason rhubarb picking stops in mid July is that the oxalic acid levels in the stems supposedly increase over the summer, whether this is true or not I don’t know I haven’t located much experimental evidence yet that confirms this common belief. There is some experimental evidence that seasonal variation of oxalic acid concentration occurs in the rhizomes and the leaves; with the concentration in the rhizomes decreasing over summer and at the same time the concentration in the leaves increases. This suggests that the oxalic acid is translocated from the rhizomes to the leaves then it appears to be recycled back to the rhizomes when the plant dies back, in which case the concentration of the oxalic acid would increase in mid to late summer in the stems as it is moves through them to the leaves.

Oxalic acid is found in dangerous concentrations in the leaves and it is important that you don’t include any leaf material when you cook your rhubarb. There are other poisonous compounds found in rhubarb leaves. However contrary to popular belief it is safe to compost the leaves.

Forced rhubarb is grown to get an early crop of sweeter and more tender stems. To force you rhubarb you need to exclude the light with a bucket or purpose made rhubarb forcing pot. First the crown is covered in compost and straw and then the pot is placed over the top usually in January. If you force your rhubarb you then need to leave the plants to recover for at least one but preferably two years without picking to restore them to their normal vigour.

There are many varieties available and it is possible to extend your season by growing early and late varieties as well as getting some variation in flavour. The most common ones are Timperley Early ; Victoria; Champagne; Stockbridge, but there are a huge number of varieties available.

Though mostly used in desserts rhubarb can be used to make jams, chutneys, fruit liqueurs, wines and as sauces for savoury dishes. Although normally eaten cooked it is possible to eat it raw, as a child I ate it raw dipped in sugar.