Rhubarb is often commonly mistaken to be a fruit but rhubarb is actually a close relative of garden sorrel and is, therefore, a member of the vegetable family.
Rhubarb leaves grow from the ground in early spring. In some countries, the leaves can grow up to a foot or more in width and length and the plant may grow to a height of several feet.
The blade or green leaves of the plant are the part that is poisonous. They contain high concentrations of oxalic acid crystals, which can cause serious problems when eaten. These crystals can cause the tongue and throat to swell, preventing breathing.
The edible petioles (stalks) can grow up to 18 in. (45cm) long, 1 to 2 in. (25mm-50mm) in diameter, generally somewhat hemispherical in cross-section. These petioles are cut and used in pies, jams, jellies, sauces, and juice. Rhubarb rhizomes and the crown persist for many years.
While seeds can be sown, rhubarb is usually planted in roots or crown form.
A piece of root with at least one bud or root is planted with the crown just at soil level. Plant outdoors as soon as the soil can be worked. Rhubarb is hardy and will survive late spring frosts. If there is a really hard frost, the leaves and stalk could be damaged, but new ones will soon replace those that are damaged.
Space two or three crowns of Rhubarb two to three feet apart and they will spread. Rhubarb tolerates a little crowding, but the stalks and leaves will grow bigger and healthier if you allow them plenty of space. A few plants are all you will need for a home garden.
Days to Maturity
It is important to allow the plant to become well established before you begin to harvest the sticks; there they should not be taken until their second or third year after planting.
Rhubarb can be picked in the spring as soon as the stalks are large enough to harvest in sufficient quantity for the recipe you are planning to use.
Before planting, select a location where they will not be disturbed for years and where they will not be in the way when tilling your garden in future years.
Rhubarb can be planted in partial shade but will do much better in full sun.
Being easy to grow, Rhubarb will thrive in most garden soils. But to ensure that better tasting, larger cropping should be your rewards; you must add plenty of manure and compost to the soil each year. Use a liquid feed during the growing season at two-week intervals for well-established plants, to promote leaf and stalk growth.
Make sure ample water is in the soil during the harvest period. After harvest, don’t forget to provide water to keep your plants healthy all year long. Healthy Rhubarb will grow and spread. Separate or thin the plants every five years or sooner if the plants become crowded.
Rhubarb is long-lived and suffers from very few diseases.
The stalks can be harvested regardless of length. When harvesting, grasp a stalk firmly close to the ground. Twist and pull the stalk and it should break free of the plant.
While harvesting, pick the largest stalks first. Don’t let them get too big, as some of the flavour will be lost. Rhubarb stalks will remain sweet and flavoursome until the warm summer weather begins and the stalks become less sweet.
Rhubarb can be forced into growing earlier. While the ground has not warmed up sufficiently for the plant to really get growing, cover a couple of plants with a five-gallon bucket, preferably black. You can also use a thick layer of straw or leaf mulch. The plants will begin growing earlier and you can harvest them days or weeks before you would normally do.