April – Rhubarb
Rhubarb is technically a vegetable as we eat the lovely pink stalks but we use it in cooking like a fruit. It is a great fruit (or vegetable) and is ready to harvest at a time when there is no other fruit available.
A short history of rhubarb
Rhubarb is thought to date back to as early as 2700 BC in China where it was originally used as for its medicinal properties. From China, rhubarb was taken to Europe most likely for trade and was even written about by Marco Polo.
It was until the late 18th century that rhubarb was written about as a food source, where it appeared in recipes for pies and tarts much like how we use rhubarb today. From Europe, rhubarb also made it across the Atlantic ocean to the Americas and was in popular use by the early 19th century.
In the UK, forced rhubarb production dates back to the 1800s by many small farmers and growers. Forced rhubarb production became much more extensive towards the late 19th and early 20th century especially in a 30 square mile area in Yorkshire (between Leeds, Bradford and Wakefield) which became known as the Rhubarb triangle. After the second world war, rhubarb popularity declined due to the availability of more exotic fruits.
Why should we eat Rhubarb?
When we talk about eating rhubarb we are talking about the stalks of the plant. You can’t eat the leaves of Rhubarb as they are toxic. This is due to the high levels of oxalic acid which is nephrotoxic (toxic to the kidneys). Oxalic acid is still present in the stalks but in much lower quantities so is not harmful but does contribute to the sour acidic taste of raw rhubarb stalks.
However, there are health benefits to eating rhubarb. The vegetable contains a lot of water so is only 21 calories per 100g. They are a good source of fibre and an excellent source of vitamin K which is vital for proper clotting of the blood and has been shown in studies to have a neuro-protective effect against diseases such as Alzheimer’s. It also contains a good source of Vitamin C as well as being a source of calcium and manganese.
How to grow Rhubarb
Rhubarb is relatively easy plant to grow and care for. In my own experience, it is not massively demanding.
Plants are normally bought from suppliers as crowns. Dormant or bare-root crowns can be planted in Autumn and early spring whilst pot grown crowns can be planted at any time.
The ground should be prepared before planting by thoroughly weeding and working in organic matter such as compost and/or well-rotted manure. Dig a hole where the rhubarb will be positioned, and if bare root, spread the roots out in the hole with the crown just poking above the top. Back fill the hole with compost and soil and firmly press the soil around the base. If the plant is pot-grown then dig a hole slightly bigger but not deeper than the pot and transplant the crown into the hole. Back-fill and press the soil firmly down around the base. Water the plant well and continue to water it to help it get established.
The rhubarb should be left to grow and you shouldn’t take any stalks from the plant in the first year. If you do this will weaken the crown and it won’t establish well. If left alone, the plant will grow and produce food and energy which will be stored in the crown. In the second year, it is best to also leave the plant alone but if you just can’t wait then taking a few sticks shouldn’t hurt it too much. In the third year you can start to harvest more and by the fourth you can crop it continuously form March until the end of June taking up to half of the stems. Never pick all the stems from the plant, always leave some behind. From July onwards, you should leave the plant alone to recover and build up energy stores once again in its crown.
Every year, the crown should be mulched well with organic matter before the buds begin to open. The plant is susceptible to hard frosts and will lose it’s foliage over the winter. Remove dead leaves so they don’t rot on the crown.
You can force rhubarb to give you an earlier crop but this will sap the crown of its energy so once you have harvested the forced stalks you should leave it alone for the rest of the year and you shouldn’t force it again for another three years.
Forcing is relatively simple. You cover the crown with a large bucket or forcing jar in January to ensure that no light is reaching the plant. Any hole is pots should be covered with brisks or stones. The stalks and leaves will grow long searching for the light and you will be rewarded with tender pink stems which are typically ready three weeks before the normal harvesting season.
Harvesting rhubarb is very simple. Pull the stems from the base of the plant by pulling and twisting. Don’t cut the stalks off as this can leave a wound were disease and infection can set in. Cut of the leaves and put them in your compost bin. Then take home your lovely rhubarb stalks!
Rhubarb doesn’t have many problems but do watch out for pests such as slugs, snails and aphids. Slugs and snails don’t tend to go for mature rhubarb plants but may attack young seedlings (if you grow from seed). The other problem to watch out for is crown rot. You can avoid this by maintaining good hygiene practices such as clearing up dead leaves and stalks promptly, harvesting stalks properly and when mulching don’t cover the crown as this can aid the onset of rot, mulch around the crown and avoid letting the mulch touch the crown.
How to cook rhubarb
Rhubarb is definately much better cooked with sugar. The sugar mellows the acid taste of the rhubarb. Rhubarb can be baked, poached or stewed and can be made into a variety of sauces, compotes, pies, tarts and crumbles. It can also be used in jams and chutneys.
- To bake rhubarb cut it into chunks, scatter with sugar, cover with foil and bake in a medium oven for about 15 minutes until soft.
- To poach rhubarb cut into sticks, scatter with sugar, add a splash of water and simmer gently for 8 minutes until soft and longer to cook it to a puree or compote.