Rhubarb is a sun-loving herbaceous perennial, with a dramatic flare. For general guidelines on growing rhubarb in an edible landscape, we recommend this write-up from California-based edible landscape designer, writer, and photographer Rosalind Creasy. Details on growing here in Charlottesville and central Virginia below.
Rhubarb stalks have delightfully rich, tart flavor that make an fine base for desserts and jams. Rhubarb is low in Saturated Fat and Sodium, and very low in Cholesterol. It is also a good source of Magnesium, and a very good source of Dietary Fiber, Vitamin C, Vitamin K, Calcium, Potassium and Manganese. Take caution to eat the stalks only; the leaves of this plant are poisonous!
Rhubarb should be planted while the roots are dormant, meaning early Spring (as soon as the ground is workable), or in the fall, after dormancy has set in again.
Choose a site in full sun, with good drainage, a slightly acidic pH, and lots of organic matter.
Prepare your bed by eliminating all perennial weeds.
Then, dig large holes, about 2 ft wide by 1 ft deep, spaced roughly 4 ft apart. Plant the roots (or crowns) 1-2 inches below the surface of the soil.
Be sure to mix your local Black Bear or homemade compost into the soil of the hole. Rhubarb plants are heavy feeders and will benefit from the extra organic matter. Take caution to NOT add a chemical fertilizer when planting rhubarb or during the first year of growth, as direct contact with nitrates can kill your plant.
Rhubarb has few pests and diseases. If sited correctly, a plant will last a lifetime with modest maintenance. Two to three plants are adequate for an average family. You can expect to harvest 2-6 pounds of rhubarb from a full-size plant. Cool, moist weather tends to increase productivity, while warm, dry conditions may reduce your harvest.
A generous layer of straw mulch or composted cow manure, applied in Spring and Fall, will provide nutrients for the plant, retain moisture, and discourage weeds.
Water your plant thoroughly. Keep soil moist, especially during dog days of the summer, but not waterlogged. Keep mulch away from the crown to avoid rot.
Remove seed stalks as soon as they appear, redirecting energy to healthy roots and stalks.
After the first Spring, apply a light sprinkling of a high-nitrogen fertilizer (like fish emulsion) when the ground is thawing or has just thawed.
Diseases and insects generally don’t bother rhubarb plants. Slow growth of older plants is usually a signal that they need dividing. Rhubarb curculio—a half-inch long, yellow-gray beetle—damages stalks and crowns by boring holes in which to lay its eggs. If curculios appear, handpick adults and destroy nearby curly dock (Rumex crispus), a weed which is an alternate host for this pest.
Do not harvest stalks during the first growing season, so that your plants can become established. Gradually increase the number of stalks and the length of time you pick in the second and third years of growth. Expect healthy plants to produce fully in the fourth year. Harvest period runs 8 to 10 weeks long for mature plants.
Harvest the stalks when they are 12 to 18 inches long, at at least 1 inch thick. If the stalks become thin, stop harvesting; this means the plant’s food reserves are low.
Grab the base of the stalk and pull it away from the plant with a gentle twist. If this doesn’t work for you, you can also cut the stalk at the base. Be sure to discard those poisonous leaves!
Always leave at least 2 stalks per plant to ensure continued production. You may have a bountiful harvest for up to 20 years without having to replace your rhubarb plants.
After harvest time, the stems may die back. Remove all plant debris. Once your ground freezes, it’s best to cover rhubarb with 2 to 4 inches of mulch, preferably well-rotted compost; by adding nitrogen to the soil, you’re preparing the rhubarb plants for a good spring season.
If not using right away, rhubarb is a great candidate for freezing.
Red rhubarb varieties are not only beautiful, but also more tender. Recommended varieties include ‘Victoria’ and ‘Crimson Red’, both available at Edible Landscaping Nursery.
For more on growing rhubarb from seed, check this excellent post from Southern Exposure Seed Exchange’s garden extraordinaire, Ira Wallace.