The chances are if you know anyone who grows rhubarb, they’ll have tried to pass some off on you in the summer. However, by this time it’s often the tough, stringy stuff that puts many people off growing and eating it themselves.
What raises rhubarb to gourmet status is the first tender, slender pink stems in April and May, and if they’ve been grown in the dark, or ‘forced’ then all the better. No one gives away these first delicious stems and you’ll only find them in the shops at an eyebrow-raising price, so the epicurean gardener must get to grips with growing their own supply.
At Hampton Court we grow three great varieties. ‘Timperley Early’ for the earliest stems, ‘Champagne’ for its delicate flavour and ‘Victoria’ which is a reliable late cropper, extending the season.
Easy to grow
Luckily, rhubarb is one of the unfussiest crops going. All it needs is some sunshine and a soil that is moist but not waterlogged. The soil at Hampton Court Palace is quite sandy and prone to drying out, but as the main growing season is April to June, this is less of a problem as there is usually adequate rainfall over the late winter and early spring. The rhubarb patch will appreciate a few spadesful of well-rotted manure just before growth begins in February to keep it in top productivity.
Rejuvenate old rhubarb
An old, neglected patch will often only throw up only weak, spindly stems due to overcrowding. If this looks familiar, the best thing is to dig up the whole root (called a ‘crown’) in winter and split it using a spade, making sure there are a few buds on each new piece. Replant these with the buds just above soil level and give a generous mulch of well-rotted manure and they should reward you with strong new growth.
When you have a strong plant that is a few years old, you can start to force it. The technique was discovered by accident when a gardener at the Chelsea Physic garden covered a plant in soil whilst digging a trench, and then realised how much tastier the stems were after they were uncovered. The plant sends up long, pale stems in search of the light, which are sweeter and tenderer. Rhubarb was only really used medicinally before then, because before cheap sugar was available it was far too tart to eat by itself.
The Victorians developed the terracotta forcing pot to cover individual plants, complete with lid to check on progress. In the rhubarb triangle in Yorkshire, warehouse sized sheds lit only by candlelight produce this delicacy en masse. However, the thrifty gardener will be pleased to hear that the same effect can be got from an upturned dustbin, or large bucket. This should be placed over the dormant plant in late January, which will hopefully give you forced shoots by April.
This artificial cropping takes a lot out of the plant so it’s best to take off the cover in late May and then give the plant a couple of years to recover before trying again, so if you want this treat every year you’ll need a few plants to cover in rotation. Plants left uncovered will crop a few weeks later, but will go on cropping until June at least. Then the heat tends to get the better of them and they become tough. Leave the plants then to grow and regain energy for next year’s harvest.
I shall be watching our plants closely this year to see the effects of the strangely mild weather we’ve had this winter. Rhubarb is a native of Siberia and needs a spell of cold weather to trigger it into vigorous growth. However, as I write this in late January, we’ve only had a handful of days here below 5 degrees. Some of the Yorkshire growers have resorted to digging up roots and refrigerating them to ensure a harvest. It’s likely to make you very unpopular at home if you fill your fridge with rhubarb crowns, so I’m hoping for a few more cold days before this winter is out.