What grows for ten years or more, suffers from almost no pests, and is refreshingly easy to care for? It’s rhubarb! This perennial vegetable has tart-flavored ruby or green stems used to make pies, crumbles, jams, and sauces. Learn how to plant, grow, and pick rhubarb correctly.
Rhubarb originally came from Asia. It was brought to Europe in the 1600s and to America shortly thereafter. It thrives in areas with a cooler climate, making it popular in northern gardens. Rhubarb is easy to grow but needs a dormancy period to thrive and produce an abundance of huge stalks. Rhubarb does best where the average temperature falls below 40ºF (4°C) in the winter and below 75ºF (24°C) in the summer.
The stalks are the only edible part of the rhubarb plant. These have a rich, tart flavor when cooked. The leaves of the rhubarb plant are toxic. They contain an irritant called oxalic acid, so be sure that they are not ingested.
What’s lovely about rhubarb is that it’s a perennial: A healthy plant will remain productive for 10 years or more. For that reason, rhubarb should be planted in its own space in any corner of the garden where it can grow undisturbed. Rhubarb grows well in soil amended with plenty of well-rotted manure or compost; this has inspired some gardeners to plant it near their compost piles!
With its ruby or green stems and umbrella-like leaves, rhubarb also adds height and structure to your garden, along with a splash of gorgeous color that will return year in and year out.
Rhubarb grows best in full sun but will tolerate partial shade.
Choose a site with soil that is well-draining and fertile. Good drainage is essential, as rhubarb will rot if kept too wet. Mix compost, rotted manure, or anything high in organic matter into the soil. Rhubarb plants are heavy feeders and need this organic matter. Learn more about soil amendments and preparing soil for planting.
Rhubarb gets big! It can grow to 2 to 3 feet tall and wide. Make sure you choose a site where it won’t be crowded.
When to Plant Rhubarb
Rhubarb can be planted in late fall or early spring.
Plant rhubarb crowns after dormancy have set in in the fall, and you’ll have rhubarb cropping in the spring!
In spring, plant crowns when the soil is workable, when the roots are still dormant, and before growth begins (or as plants are just beginning to leaf out). If you have a temperature gauge, soil temperature should be 50°F minimum.
How to Plant Rhubarb
Plant 1-year-old rhubarb crowns, which you can find at a garden center, or nursery, or order online. Plants will be sold as bare-rooted specimens or young plants already growing in pots, ready for transplanting. (Rhubarb can be grown from seed, but this is not recommended.)
Before planting, eliminate all perennial weeds in the planting site.
Dig large, bushel-basket-size holes.
Space rhubarb plants about 2 to 4 feet apart and 3 to 4 feet between rows.
Plant crowns so the eyes are about 2 inches below the soil surface with buds facing up.
Water well at the time of planting.
Check out this video to learn more about how to plant rhubarb:
Overcrowding is a common problem with rhubarb and can lead to subpar growth. Dig and split rhubarb roots every 3 to 4 years. Divide when plants are dormant in early spring (or late fall). Divisions should have at least one large bud on them.
Mulch generously with a heavy layer of straw to retain moisture and discourage weeds.
Water your plant well and consistently. Rhubarb needs sufficient moisture, especially during the hot, dry summer days.
Remove seed stalks as soon as they appear, as they will only drain energy from the plant that could be used to produce stalks or roots.
Each spring, apply a light sprinkling of a fertilizer (10-10-10) when the ground is thawing or has just thawed. See your local frost dates.
In the fall, remove all plant debris. Once your ground freezes, it’s best to cover rhubarb with 2 to 4 inches of organic mulch, preferably well-rotted compost. By adding nitrogen to the soil, you’re preparing the rhubarb plants for a good spring season.
These common varieties have attractive red stalks and excellent growers:
In addition to the previous four, there is a reliable, green-stalked cultivar named:
Do NOT harvest any stalks during the first growing season. Harvest sparingly in the second year. This allows your plants to become properly established.
After a plant’s third year, the harvest period runs 8 to 10 weeks long, lasting through mid-summer.
Harvest stalks when they are 12 to 18 inches long and at least 3/4-inch in diameter. If the stalks become thin, stop harvesting; 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, you can cut the stalk at the base with a sharp knife. To prevent the spread of disease, be sure to sanitize the knife before cutting. Discard the leaves.
Always leave at least two stalks per plant to ensure continued production. You may have a bountiful harvest for well over ten years without replacing your rhubarb plants.
It was once believed that the entire rhubarb plant became toxic as summer temperatures rose. This isn’t true, although summer-harvested stalks usually have a tougher texture than those picked in the spring. Nevertheless, after mid-summer (July), it’s best to leave stalks on the plant to allow them to gather energy for next year’s growth.
How to Store Rhubarb
Cut the rhubarb stalks and refrigerate in a covered container. Or, tightly wrap stalks in plastic or aluminum foil and refrigerate. Rhubarb can be kept fresh in the refrigerator for a couple of weeks.
Cut rhubarb stalks into pieces, place them in a covered container or zip-type plastic bag, and put them in the freezer. Frozen rhubarb will last about a year.
Varies; yellow/ brown/gray spots with water-soaked margins on leaves/flowers; gray mold; buds remain closed; stem lesions; wilt/rot; scorched appearance (“fire”) in some plants
Destroy infected parts/severely infected plants (do not compost); remove plant debris regularly; disinfect tools; good air circulation/sunlight; avoid overhead watering; prevent plant stress/injury; weed; rotation
Fungal leaf spot
Varies; leaf spots on lower leaves enlarge and turn brown/black; fuzzy growth or pustules in lesions; disease progresses upward; leaves die
Destroy infected leaves/ severely infected plants (do not compost); remove plant debris regularly; disinfect tools; resistant varieties; good air circulation; avoid overhead watering
Phytophthora crown and root rot
Leaves discolor/ wilt; dieback; oozing cankers near base; reddish brown discoloration of inner bark/wood; roots rot; plants slow-growing/stunted/die
Destroy infected plants and surrounding soil (do not compost); prune out branch cankers; remove plant debris regularly; plant resistant varieties; prevent plant stress/injury; provide good drainage/do not overwater
Weevil-like beetle that bores into stalks/crowns; notches on stalks/leaves; holes in stalks leak sap; plants wilt/decay
Handpick adults (appear in mid-May); destroy nearby host plants (sunflowers, thistle, dock) in mid-summer (July)
Irregular holes in leaves; slimy secretion on plants/soil; young stems “disappear”
Handpick; avoid thick bark mulch; use copper plant collars; avoid overhead watering; lay boards on soil in evening, in morning lift and dispose of pests in hot, soapy water; drown in deep container of 1/2 inch of beer or of sugar water and yeast sunk to ground level; apply 1-inch-wide strip of diatomaceous earth