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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>Lori N.</span> Tue, 05/05/2015 - 15:30
Yes, that stalk should be cut back to the base as low as possible without damaging the rest of the plant. You can do it now without waiting for flowers.
<span>James Harrison</span> Sun, 04/26/2015 - 11:01
What is that stalk that is growing in the middle of the rhubarb, we have had the plant for 4 years now and never seen this before
<span>Lori N.</span> Tue, 05/05/2015 - 15:32
Congratulations, your rhubarb has matured! That is the flower stalk. It should be cut back to the base as low as possible without damaging the rest of the plant. You can do it now without waiting for flowers.
<span>Ruth Perkins</span> Tue, 05/12/2015 - 15:53
I planted some Heirloom Victoria Rhubarb seeds in spring of last year, 2013. How long do I have to wait until the stalks are safe to eat? I also planted an Heirloom Victoia Rhubarb seedling I got from a store. It is at least 1 year old now and beginning to flower. I know I need to remove the flower but does the flower indicate that the plant is mature enough to eat? Thanks
<span>Barbara Redmond</span> Wed, 04/29/2015 - 15:09
is it like a round bulb of some sort growing in the middle of everything? i have it this year (about 4th year) and never saw it before. if you learn what it is, please write me. thank you.
<span>Lori N.</span> Tue, 05/05/2015 - 15:36
Yes, that is the flower stalk. It should be cut back to the base as low as possible without damaging the rest of the plant.
<span>Betka</span> Mon, 04/13/2015 - 11:59
We live in Wyoming where we have tried to start rhubarb growing 4 or 5 times. We finally have sprouts, from a friend's bulbs! However, it looks like it will be necessary for us to transplant the rhubarb from a greenhouse to a sunnier, better drained location. My problem is that we have voles, which tend to destroy the roots of plants by burrowing. Do the roots of rhubarb have pest-repellent properties like the leaves, or do you have any other suggestions for protecting the roots? We have mesh in the bottom of our greenhouse bed, but it seems like that could be a problem too, if the rhubarb roots go as deep as you say. Thanks!
<a title="View user profile." href="/author/editors">The Editors</a> Tue, 04/14/2015 - 10:51

There is not easy solution to voles; it sounds like you're trying all the right things. One source suggests encouraging natural predators: raptors, owls, raccoons, coyotes, foxes, snakes—even dogs and cats.

As for your rhubarb, if you think your greenhouse bed is not safe, you could plant in containers. Large ones, to be sure, but these you could control placement. If you move a "starting" plant, you may loose it; best to move the root to a container in the fall.

How does your friend defeat the voles?

 <span>Janet Collison</span> Tue, 03/10/2015 - 00:25
I need to move an old rhubarb plant, it is in a confined space. I am hoping for some advice. How deep does the root system go? How can I do the least damage to the plant? If I divide it when I pull it will I still be able to get usable stalks this year?
<a title="View user profile." href="/author/editors">The Editors</a> Tue, 03/10/2015 - 11:35

Early spring, before new growth starts, is the best time to transplant rhubarb, with fall second best (after leaves have died back). If you transplant the entire plant, dig down as deep as you can (about 12 to 18 inches deep and 8 to 12 inches away from the buds), and include a good portion of the soil around the roots. Avoid damaging the crown or buds. Rhubarb roots on older plants can extend several feet deep, so it is not likely that you will be able to get them all, but that is OK. Note that the root ball may be heavy to transport! It may be easier to divide the plant before transplanting. If dividing, make sure each section contains 1 to 3 buds and a portion of roots. See the article above as to how to prepare the soil and plant in a new spot.



If you divide the plant, leaving part of the mother plant intact in the original spot, you might get a reduced harvest from the mother plant this year. Do not harvest from the transplanted sections until they become established in 1 or 2 years; after that, they can be harvested lightly the first year and then normally in subsequent years.



For more advice, you might be interested in:

http://www.ipm.iastate.edu/ipm/hortnews/2006/2-8/rhubarb.html

root depth of rhubarb:

http://www.soilandhealth.org/01aglibrary/010137veg.roots/010137ch7.html