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Planting and Growing Rhubarb

Botanical Name
Rheum rhabarbarum
Grown as
Perennial
USDA Zones
3a
3b
4a
4b
5a
5b
6a
6b
7a
7b
Toxicity
Toxic to Dogs and Cats
Sun Exposure
Full Sun
Partial Sun
Water Needs
Moderate
Height
3-6 feet
Spread
3-6 feet
Soil pH
Acidic
Neutral
Special Features
Cut Flower
Low Maintenance
Attracts Pollinators
Deer-resistant
Rabbit-resistant
Resilience
Cold Hardy
Plant Type
Vegetables
Written By: Catherine Boeckmann Executive Digital Editor and Master Gardener

What grows for 10 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, cakes, jams, and sauces. Learn how to plant, grow, and pick rhubarb correctly.

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.

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!

Planting

When to Plant Rhubarb

  • Rhubarb can be planted in late fall or early spring.
    • Plant rhubarb crowns after dormancy has 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.

Spacing for Rhubarb

Where to Plant Rhubarb

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. 

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:

Growing

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 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.

Rhubarb leaf

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 (rhubarb season!) 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 10 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 midsummer (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.

Pests and Problems

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

Rhubarb Pests and Diseases
Pest/DiseaseTypeSymptomsControl/Prevention
Botrytis (gray mold)FungusVaries; 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 plantsDestroy 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 spotFungusVaries; leaf spots on lower leaves enlarge and turn brown/black; fuzzy growth or pustules in lesions; disease progresses upward; leaves dieDestroy 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 rotOomyceteLeaves discolor/ wilt; dieback; oozing cankers near base; reddish brown discoloration of inner bark/wood; roots rot; plants slow-growing/stunted/dieDestroy 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 curculioInsectWeevil-like beetle that bores into stalks/crowns; notches on stalks/leaves; holes in stalks leak sap; plants wilt/decayHandpick adults (appear in mid-May); destroy nearby host plants (sunflowers, thistle, dock) in mid-summer (July)
Slugs/snailsMolluskIrregular 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

Toxicity
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.

Types

These common varieties have attractive red stalks and excellent growers: 

  • ‘Canada Red’
  • ‘Crimson Red’
  • ‘MacDonald’
  • ‘Valentine’

In addition to the previous four, there is a reliable, green-stalked cultivar named:

  • ‘Victoria’

Wit and Wisdom

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

Vegetables

About The Author

Catherine Boeckmann

Catherine Boeckmann

Executive Digital Editor and Master Gardener

Catherine Boeckmann loves nature, stargazing, and gardening, so it’s not surprising that she and The Old Farmer’s Almanac found each other. She leads digital content for the Almanac website and is also a certified master gardener in the state of Indiana.

Read more from Catherine Boeckmann

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Comments

<span>Elaine Smith</span> Sat, 07/21/2018 - 17:49
The 4th of July cutoff date is not because of any danger of poisoning. The eight to ten weeks of harvesting has passed and the plant now needs to feed the roots and prepare for next years production. The quality of the stalks usually has deteriorated as well but are not dangerous. The flower stalks have no effect on the plants edibility. They are removed so the plant can use its energy to produce stalks instead of seeds.
<span>Melissa</span> Wed, 06/13/2018 - 13:37
Hello, we moved into a house that has 2 huge, old Rhubarb plants. It looks like they were ignored for a few years. Should they be cut back to almost nothing? They already have seed heads on them. Thanks
<a title="View user profile." href="/author/editors">The Editors</a> Thu, 06/14/2018 - 12:02

Cut off the flower stalk—not the leaf stalks—at the base (don’t twist the flower stalk; instead, use a knife or pruning shears to make a clean cut on these tougher stalks). This way, the plant can focus its energy on forming leaf stalks (which might be useful to you now!). To help prevent bolting again this year, add mulch to keep roots cool during warm spells. Be sure that the plant is getting enough water, light, and nutrients, and isn’t overcrowded. Add lots of organic matter in fall. You should have many happy harvests in your future!

 <span>Al</span> Thu, 05/31/2018 - 16:48
Large leaves and stalks, overall appears quite healthy. I have almost no red coloring on stalks. Is this normal? Can I still harvest ?
<a title="View user profile." href="/author/editors">The Editors</a> Fri, 06/01/2018 - 15:41

Because your rhubarb is in its third year, we'll assume it's not just a white variety. Perhaps your plant is getting too much sun. If the stalks are the right size for harvesting, try cutting off one to test, then take the rest if it seems ready. If not, let it mature a bit more.

 <span>Diane Gerst</span> Tue, 05/29/2018 - 16:22
I am a senior citizen and have had a hard time finding rhubarb to purchase, so last year I purchased a rhubarb plant and planted it in a large pot. I put it in the garage to keep through the winter as it gets very cold here at times.. it continued to grow in the garage! I then made sure I kept it watered occasionally. It now is just producing thin stalks that aren't large enough to break off for cooking. I was planning to repot it. Would it help or harm the plant or have I runined it already? Also would I need more than one plant to have enough to make a pie etc.? Thank you
<a title="View user profile." href="/author/editors">The Editors</a> Thu, 05/31/2018 - 09:37

Congratulations on keeping the rhubarb going in the garage. It must be in good soil in a good place. Thin stalks are typical of a first-year plant. As noted above, it is best not to harvest in the first year. You can repot it; this should not harm the plant. Set it in plenty of organic/composted matter and it should thrive. As for how much would you need for a pie, this one requires 2 1/2 cups: https://www.almanac.com/recipe/strawberry-rhubarb-pie-coconut-crumb-topping

You can see more rhubarb recipes, using varying amounts, that might appeal to you, too: https://www.almanac.com/content/best-rhubarb-recipes

 <span>Judy Little</span> Mon, 05/21/2018 - 16:02
Our rhubarb is well established. We moved it once for this exact reason thinking that was the case. The stalks do not turn red and the plants (we have 20 or so) all bolt quickly. Is there any truth to the male female stalks like corn has?
<a title="View user profile." href="/author/editors">The Editors</a> Tue, 05/22/2018 - 16:49

It's natural for rhubarb to flower and go to seed. However, you can delay that stage a few ways: Grow Canada Red or Valentine varieties; they are less likely to bolt that "old-fashioned" varieties such as Victoria and MacDonald (these are heavy stalk producers). Older/more mature plants are more likely to bolt than younger ones, although dividing every 4 to 5 years, as it sounds like you did, can essentially rejuvenate mature plants. Applying fertilizer (a balanced type, e.g. 12-12-12) or well composted manure in spring can also delay/discourage bolting. If your plant volts/produces flowers, it is recommended that you remove them, so it will focus its energy on producing leaves.

We are not familiar with rhubarb compared with corn, but the stem and leaf tissue of rhubarb can be damaged by the European corn borer larvae, which as the name indicates is a pest of corn, both sweet and grain.

 <span>Candy Walker</span> Sun, 05/20/2018 - 19:13
My rhubarb doesn’t get big enough to eat. The leaves are getting holes I assume from a bug of some type. People talk about flowers as part of the rhubarb but i’ve never had any flowers. HELP!!