Rheum

This is a group of herbaceous perennials, some of which are grown for ornament and some for food.

Ornamental - Ornamental Rhubarb is grown for its attractive foliage and flowers. They are found wild in China, the Himalayas and Siberia. Since these plants grow very large, they will need plenty of room. R. palmatum can grow up to 5 feet high and has pale green, palmate leaves and crimson flowers. R. emodi has bronze-green foliage and purple blossoms and R. Alexandrae has shiny green leaves and pale yellow bracts.

Vegetable - R. rhabarbarum is the botanical name for the edible Rhubarb plant, also known as the Pie Plant. Rhubarb is a robust perennial that is grown for its plump, pinkish to red leafstalks, which have an agreeable acid taste; these are used to make tart, pies, or as a base for wine. The stalks grow 1 to 22 feet high. Large, reddish-green leaves, up to 18 inches across, grow from these stalks. Rhubarb leaves can be handled safely, though they are poisonous if ingested. Cut off all green leaf matter before using the stalks.

Pot Cultivation

Ornamental - These plants are easy to grow. They need a large space and deeply dug, well manured soil. Place the plants 4 to 6 feet apart in early autumn or spring. Water well in dry weather and give an annual mulch of decayed manure. It is beneficial to provide the simple protection of evergreen branches, salt hay, or dry leaves during the winter in Northern climates.

Vegetable - It is very important to prepare your soil properly. In early spring, a bed 3 feet by 10 feet should be made. Dig in two or three large bags of steam-pasteurized cattle manure to spade depth. Add lime fertilizer if needed. All these ingredients will raise the bed. Cover the bed with landscape cloth or black plastic and cut out small openings. The plants/seeds will be inserted here. You will only need 2 or 3 plants and they should be spaced 3 feet apart. Once in a while, a hose should be inserted into a hole and allowed to trickle for a half hour or so. Rhubarb should be in a position full of sun. In regions with warm summers, plants will need some afternoon shade. Use plastic mulch or lay moistened newspapers thickly over the bed and cover with dried lawn clippings. Snails, earwigs and slugs should be controlled by using metaldehyde plus carbaryl pellets. These plants require winter dormancy and may die where winters are mild. In regions with harsh winters, plant tops will freeze to the ground. Mulch each winter with a mixture of compost, potash sources and phosphate, 2 to 3 inches into the ground. Rhubarb can be harvested in the second growing season. From spring through early summer, carefully snap off the outer stalks at the base. (Don't use a knife, which could slip and sever the growing point.) Harvest sparingly so that you don't shock the plant; stop when you have taken about half the new growth.

Propagation

Ornamental - Lift and separate the plants into pieces in early spring or fall.
Vegetable - It is better to use root divisions of Rhubarb. You can grow them from seed, but production will take about a year longer and the stalks will be thinner and paler.

R. palmatum

Varieties

Ornamental - R. palmatum; R. emodi; R. Alexandrae.
Vegetable - Cherry Red, Valentine and MacDonald are all good varieties to start from plants and are more uniform than seed-grown Rhubarb. Victoria is the only variety widely available from seeds.