How To Grow Rhubarb

To grow rhubarb successfully, plant dormant crowns or seeds in well-drained, fertile soil with full sun to partial shade. Space plants 3-4 feet apart and water deeply but infrequently. Apply compost annually and avoid harvesting the first year. Harvest stalks by pulling, not cutting, and never consume the leaves, which are toxic.

Understanding Rhubarb: The Pie Plant

Rhubarb (Rheum rhabarbarum) is a hardy perennial vegetable, though it’s often treated as a fruit in culinary applications. Known affectionately as the “pie plant,” it produces large, triangular leaves atop thick, colorful stalks (petioles) that range from deep crimson to speckled pink and light green. A well-established rhubarb plant can be highly productive, yielding harvests for 8 to 15 years or even longer, making it a fantastic investment for any garden. It’s crucial to understand that while the stalks are delicious, the leaves contain high levels of oxalic acid and are poisonous if ingested.

Why Grow Your Own Rhubarb?

There are countless reasons to dedicate a spot in your garden to rhubarb. Store-bought rhubarb can be expensive and is often picked too early, resulting in less flavor. Homegrown rhubarb, allowed to mature fully on the plant, has a superior, complex tartness that is simply unmatched. You also have access to a wider variety of cultivars, each with unique colors and flavor profiles. Furthermore, it’s a remarkably low-maintenance plant once established, requiring minimal effort for a massive payoff in early summer desserts, jams, and compotes.

A Brief History of Rhubarb Cultivation

Rhubarb has a fascinating history that spans continents. Its use dates back to ancient China in 2700 BC, where it was primarily cultivated for its medicinal roots. It made its way to Europe along the Silk Road and was initially used for the same medicinal purposes. It wasn’t until the 18th century in Britain, when sugar became more affordable and widely available, that cooks began using the tart stalks for pies and desserts. This culinary shift cemented rhubarb’s place in the modern garden and kitchen.

Choosing the Right Variety for Your Garden

Selecting a variety is your first step toward a successful harvest. Consider your climate and desired use (e.g., for vibrant color in desserts or for canning).

• Victoria:
A classic green variety with pink speckles. It’s extremely reliable, vigorous, and prolific, though its color is less vibrant when cooked. An excellent choice for beginners.
• Canada Red (or Crimson Red):
Known for its exceptionally sweet, thick, and vibrant red stalks that retain their color beautifully after cooking.
• Valentine:
Prized for its deep red color all the way through the stalk and its excellent resistance to crown rot.
• Glaskin’s Perpetual:
A unique variety that can be grown from seed and is often harvested lightly in its first year. It tends to produce smaller but more numerous stalks over a longer season.

Site Selection and Soil Preparation

The foundation of a healthy, long-lived rhubarb plant is the soil it’s planted in. Taking the time to properly prepare the site will pay dividends for a decade or more.

Sunlight and Location Requirements

Rhubarb thrives in a location that receives at least 6-8 hours of direct sunlight each day. In hotter climates (USDA zones 8 and above), providing some light afternoon shade can help prevent the leaves from wilting and reduce stress on the plant. Choose a site with good air circulation to help prevent fungal diseases but protected from strong, damaging winds. Remember, this is a permanent fixture in your garden, so avoid placing it where it will be shaded by future tree growth or where you might want to install a shed later. For those with space constraints, learn about Growing Rhubarb In Pots.

Ideal Soil Conditions for Thriving Plants

Rhubarb demands deep, well-draining, fertile soil. It is a heavy feeder and will not perform well in heavy, waterlogged clay or dry, sandy soils. The ideal soil is loamy, rich in organic matter, with a slightly acidic to neutral pH between 6.0 and 7.0.

Step-by-Step Guide to Preparing Your Planting Bed

1. Test Your Soil: A soil test is highly recommended to determine pH and nutrient levels.
2. Amend the Soil: Dig a hole at least 18 inches deep and 24 inches wide for each crown. Mix the native soil with a generous amount of well-rotted manure or compost—aim for a 50/50 mix. Add a handful of bone meal or a balanced organic fertilizer to the bottom of the hole.
3. Create a Mound: For areas with less-than-ideal drainage, plant rhubarb in a raised mound or consider How To Grow Rhubarb In A Raised Bed to ensure perfect drainage.

Planting Rhubarb: Crowns vs. Seeds

While you can learn How To Grow Rhubarb From Seed, most home gardeners start with purchased crowns or divisions from a friend’s established plant for a much quicker harvest.

Starting from Crowns (The Recommended Method)

Plant dormant crowns in early spring as soon as the ground is workable. Place the crown in your prepared hole with the growing buds (or “eyes”) 1-2 inches below the soil surface. If planted too deep, the buds may rot. Space plants 3 to 4 feet apart in all directions to accommodate their massive mature size. Backfill the hole with your soil-compost mixture, firm it gently, and water thoroughly.

Starting from Seeds

Starting from seed requires more patience, as you must wait an extra year before harvesting. Start seeds indoors 8-10 weeks before the last frost date. Soak seeds in water for a few hours before sowing to improve germination. Transplant seedlings outdoors after all danger of frost has passed, hardening them off gradually. You will not be able to harvest any stalks from seed-grown plants in their first year.

Timing and Spacing for Optimal Growth

The absolute best time to plant rhubarb is in early spring. Fall planting is also possible in milder climates, but spring planting gives the crown a full season to establish its root system before winter. Proper spacing is non-negotiable. Crowded plants will compete for nutrients and water, leading to smaller stalks and increased susceptibility to disease. A spacing of 3-4 feet allows for ample air circulation and sunlight penetration.

Essential Rhubarb Care and Maintenance

Consistent care, especially in the first few years, is key to building a strong, productive plant.

Watering: How Much and How Often?

Rhubarb requires consistent moisture but despises “wet feet.” Provide about 1 inch of water per week through rainfall or irrigation. Water deeply at the base of the plant to encourage deep root growth, rather than frequent shallow watering. A soaker hose or drip irrigation system is ideal. Significantly reduce watering in late fall as the plant goes dormant.

Fertilizing for Maximum Yield

Feed your rhubarb twice a year. In early spring, as growth begins, side-dress the plant with a generous shovelful of well-rotted manure or compost. You can also use a balanced organic fertilizer (e.g., 10-10-10). Avoid high-nitrogen fertilizers, as they promote lush leaf growth at the expense of stalk development. A second, lighter feeding after the harvest season ends in mid-summer will help the plant recover and store energy for next year.

The Importance of Mulching and Weed Control

A 2- to 4-inch layer of organic mulch (straw, shredded leaves, or compost) is incredibly beneficial. It conserves soil moisture, suppresses weeds, keeps the soil cool, and adds organic matter as it decomposes. Keep mulch a few inches away from the crown itself to prevent rot. Weeds compete fiercely with rhubarb for resources, so keep the area around your plants meticulously weeded, especially while the plants are young.

Harvesting Your Rhubarb the Right Way

Harvesting requires discipline to ensure the plant’s long-term health.

When to Harvest (The Golden Rule)

The most important rule is: DO NOT harvest any stalks from a new plant in its first year. This allows all its energy to go into building a strong root system. In the second year, you can harvest lightly for 2-4 weeks, taking only a few of the largest stalks at a time. By the third year, the plant is mature enough to handle a full harvest season of 8-10 weeks. For more on this critical first year, read What To Do With First Year Rhubarb.

The Correct Technique for Pulling Stalks

Never cut rhubarb stalks with a knife, as the leftover stump can rot and invite disease into the crown. Instead, grasp a thick, mature stalk near its base, twist it gently, and pull it sideways and away from the plant. It should cleanly separate from the crown. Immediately trim off the large leaf blade and discard it (do not compost it if pets or wildlife have access to the compost).

How Long and How Much to Harvest

The harvest season typically runs from April through June, depending on your climate. Always stop harvesting by mid-summer (around the 4th of July is a common marker) to allow the plant to regenerate its leaves and store energy for next year’s crop. Never remove more than one-third to one-half of the stalks from a plant at one time, and always leave at least 4-5 stalks to keep the plant healthy.

Seasonal Care and Overwintering

Rhubarb is very cold-hardy, but a little seasonal attention ensures it emerges strong every spring.

Spring Startup and Maintenance

In early spring, remove any winter mulch and clear away old debris from the crown. This is the perfect time to side-dress with compost and fertilizer. As flower stalks (seed heads) appear, cut them off immediately at their base. Allowing the plant to flower and set seed diverts significant energy away from producing edible stalks.

Summer Care After Harvest

After the harvest season ends, your plant will look a bit ragged. Allow it to grow its leaves freely for the rest of the summer. This is its recovery period. Ensure it gets adequate water, especially during dry spells, and consider that light summer feeding to aid recovery.

Fall Cleanup and Winter Preparation

After the first hard frost kills the foliage, the leaves will collapse. You can cut the dead leaves and add them to the compost pile (the oxalic acid breaks down during composting). Once the ground is frozen, a light mulch of straw or leaves can be applied to protect the crown from freeze-thaw cycles that can heave it out of the ground. Avoid using heavy, dense mulch that can trap moisture and cause rot.

Propagating and Dividing Rhubarb

Dividing mature plants is necessary for their health and a great way to get free plants.

Why and When to Divide Your Plants

Rhubarb plants should be divided every 5-8 years, or when you notice the center of the crown becoming woody and hollow and the stalk production decreasing and becoming thinner. This is a sign the plant is overcrowded. The best time to divide is in early spring, just as the buds are beginning to swell, or in late fall when the plant is dormant.

Step-by-Step Division Process

1. Use a sharp spade to dig around and lift the entire clump out of the ground.
2. With a sharp knife or spade, cut the crown into sections. Each division must have at least 1-2 large, healthy buds (“eyes”) and a sizable portion of the root system attached.
3. Discard the old, woody center of the plant.
4. Replant the healthy divisions immediately in your prepared soil, following the same planting instructions as for new crowns.

Caring for New Divisions

Treat your new divisions as first-year plants. Water them well after planting and do not harvest any stalks from them for the entire first year after division. This gives them a full season to re-establish a strong root system.

Troubleshooting Common Rhubarb Problems

Rhubarb is generally trouble-free, but a few issues can arise. For a deep dive, see our guide on Rhubarb Growing Problems.

Identifying and Treating Common Pests

• Slugs and Snails: They chew irregular holes in the leaves. Control with beer traps, diatomaceous earth, or hand-picking at night.
• Rhubarb Curculio: A large, rusty-colored beetle that bores into stalks and crowns. Hand-pick and destroy any beetles you find.
• Aphids: These small insects cluster on the undersides of leaves. A strong blast of water from a hose is often enough to dislodge them.

Preventing and Managing Diseases

• Crown Rot: Caused by fungal pathogens in waterlogged soil. Symptoms include a soft, mushy, and foul-smelling crown. Prevention is key: ensure excellent drainage and avoid planting too deep. There is no cure; infected plants must be dug up and destroyed.
• Leaf Spot: Fungal diseases that cause small, reddish-brown spots on leaves. Improve air circulation, avoid overhead watering, and remove and destroy severely infected leaves. Fungicides are rarely necessary in a home garden.

Addressing Environmental Stressors

• Thin, Spindly Stalks: Usually caused by overcrowding, inadequate sunlight, or a need for division and fertilizer.
• Failure to Thrive: Often linked to poor soil drainage or nutrition. Re-evaluate your site and amend the soil accordingly.

Frequently Asked Questions (FAQ)

1. Can you eat rhubarb raw?
Yes, you can eat the stalks raw, but they will be extremely tart. Most people dip them in sugar or honey. Always remember that the leaves are toxic and must never be eaten.

2. Why is my rhubarb green and not red?
Color is primarily determined by variety. Some cultivars, like ‘Victoria’, are naturally greener. Sun exposure can also influence color; stalks developing in full sun often develop a richer red hue.

3. Is it safe to harvest rhubarb after the first frost?
No. A hard frost can cause oxalic acid from the leaves to migrate into the stalks, making them potentially toxic. Only harvest stalks before the first fall frost. Spring frosts are not a concern for the stalks.

4. My rhubarb is flowering. What should I do?
Immediately cut the flower stalk off as close to the base as possible. Flowering (bolting) signals the plant is stressed, often by age, drought, or poor soil. Removing the flower redirects energy back to the roots and stalks.

5. Can I grow rhubarb in a hot climate?
It is challenging but possible in USDA zones 8-9. Choose a heat-tolerant variety, provide afternoon shade, and ensure consistent moisture. The plants will likely have a shorter lifespan and may go dormant early in the summer heat.

6. Why are my rhubarb stalks so thin?
Thin stalks are a classic sign of an overcrowded plant that needs to be divided. It can also be caused by insufficient sunlight, lack of nutrients, or harvesting too much too soon.

7. Can I use rhubarb leaves for anything?
While poisonous to ingest, the leaves have some practical uses. They make a natural, effective insecticide when boiled in water (the cooled liquid can be sprayed on aphids). They can also be added to your compost pile in moderation.

8. How can I force rhubarb for an early harvest?
“Forcing” involves excluding light from the crown in late winter to produce tender, pale pink stalks early. In late winter, cover the crown with a specialized forcing pot or a large, upturned bucket. Block any drainage holes. Harvest the tender stalks that grow in the dark about 4-6 weeks later. This process is taxing on the plant, so do not force the same plant two years in a row.