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Rhubarb: Planting, Growing, and Harvesting Rhubarb | The Old Farmer's Almanac

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Rhubarb

Botanical Name
Rheum rhabarbarum
Plant Type
Vegetable
Sun Exposure
Full Sun
Part Sun
Soil pH
Neutral to Slightly Alkaline
Slightly Acidic to Neutral
Hardiness Zone
3
4
5
6
7
8
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Planting, Growing, and Harvesting Rhubarb

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What grows for 10 years or more, suffers from almost from no pests, and is refreshingly easy to grow? It’s rhubarb! This perennial vegetable has tart-flavored ruby or green stems used to make pies, crumbles, jams, and sauces. Plant in late autumn or early spring when the soil is workable. Learn everything you need to know to grow and care for your own rhubarb.

About Rhubarb

Rhubarb originally came from Asia. It was brought to Europe in the 1600s and to America not long 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 really 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 wonderful about rhubarb is that it’s a perennial: It will produce for many years, five 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 just go ahead and 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. 

Planting

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 in early spring.
    • In fall, plant rhubarb crowns after dormancy has set in, and you’ll have rhubarb cropping in the spring!
    • In spring, plant crowns as soon as 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.

Spacing for Rhubarb

How to Plant Rhubarb

  • Plant 1-year-old rhubarb crowns, which you can find at a garden center, nursery, or order online. Plants will be sold as bare-rooted specimen 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:

Growing

Overcrowding is 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 days of summer. 
  • Remove seed stalks as soon as they appear, as they will only drain energy from the plant that could otherwise be used for producing 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 an organic mulch, preferably well-rotted compost. By adding nitrogen to the soil, you’re preparing the rhubarb plants for a good spring season.

Rhubarb leaf

Recommended Varieties
  • ‘Canada Red’
  • ‘Cherry Red’
  • ‘Crimson Red’
  • ‘MacDonald’
  • ‘Valentine’
  • ‘Victoria’
  • ‘Riverside Giant’
Harvesting

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; 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, 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 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.
  • It was once believed that the entire rhubarb plant becomes 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, 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 in pieces and place in a covered container or zip-type plastic bag, and put in freezer. Frozen rhubarb will last about a year.

Wit and Wisdom

Rhubarb has many other uses, from medicinal to cosmetic. See how to naturally lighten your hair with rhubarb. 

Pests/Diseases

Pests and diseases are rarely an issue with rhubarb, but they may be affected by the following problems.

Rhubarb Pests and Diseases
Pest/Disease Type Symptoms Control/Prevention
Botrytis (gray mold) Fungus 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 Fungus 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 Oomycete 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
Rhubarb curculio Insect 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)
Slugs/snails Mollusk 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
Recipes
Strawberry-Rhubarb Pie
Blueberry-Rhubarb Jam
Rhubarb Upside-Down Cake
Cooking Notes

Check out our list of best rhubarb recipes to put your fresh rhubarb to good use! Plus, learn how to make a rhubarb tonic.

Gardening
Vegetables

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Comments

Borak (not verified)

3 months 3 weeks ago

Can we use the leaves, & trimmings after we prune our rhubarb in the compost & mulch for that rhubarb?

They could be used as mulch as long as they aren’t diseased, but it would be better to use something like straw instead. It offers better protection.

Carol Snow (not verified)

5 months 2 weeks ago

When is the best time to pick rhubarb and once it goes to seed at the top, what is the best thing to do?

Rhubarb is best when it’s fresh in the spring or early summer. The older stalks may become too fibrous after that. It’s best to prune off the blooms or developing seeds so that the plant doesn’t waste energy.

Shirley Hauger (not verified)

7 months 2 weeks ago

My aunt wants to know if you plant the blooms off the rhubarb?