What to Know About Growing Rhubarb

Rhubarb is an easy-going perennial vegetable grown for its long, tart, reddish stalks that resemble rosy celery. Its most common uses include making sweet preserves and baked goods. In this post, you’ll discover all the essentials about growing rhubarb and enjoy a generous harvest for many years to come.

This perennial plant grows best in cool climates where the winters are cold enough for a dormancy period of at least six weeks. Choose a location for planting rhubarb where it can grow undisturbed year after year.

The large leaf stalks are the only edible part of rhubarb plants. They’re intensely tart and normally get cooked before eating. Rhubarb leaf tissue contains high levels of oxalic acid, which is toxic to humans and animals. Ensure that pets and livestock don’t have access to rhubarb plants.

With the right growing conditions, rhubarb is a low-maintenance vegetable that rewards your efforts for ten years or more. Keep reading to learn all about how to grow rhubarb in your home garden.

Best Tips and Tricks for Growing Rhubarb

Rhubarb, or Rheum rhabarbarum, is native to China. It was first introduced to Europe and North America in the 17th century. It’s a member of the buckwheat family (Polygonaceae) and gets cultivated for its edible leaf stalks or petioles.

Rhubarb’s primary use was medicinal before sugar became more readily available and less expensive in the 18th century. It’s rich in antioxidants, calcium, fiber, potassium, and vitamin C and K. Rhubarb’s many health benefits include regulating blood pressure, lowering cholesterol, supporting eye health, and reducing the risk of chronic diseases.

Although a sugary strawberry rhubarb pie may be one of the rhubarb recipes that comes to mind, there are numerous culinary uses for rhubarb stalks. If your sweet tooth runs out, try preparing savory rhubarb recipes like a chicken marinade or rhubarb chutney.

Planting Rhubarb Crowns

Most gardeners choose to plant one-year-old rhubarb crowns, as growing them from seed is more labor-intensive and takes much longer. Purchase rhubarb crowns from your local garden center or a reliable online retailer. Or, if you know someone with an established plant ready for dividing, transplant a rhubarb clone.

The best time for planting rhubarb is late fall or early spring when the root system is dormant. Rhubarb plants grow to be four or five feet wide when mature, so give them plenty of space.

For the best possible results, loosen the soil around your planting hole for 12 inches in all directions so the roots can begin spreading out. Plant the rhubarb crown about four inches deep, then loosely cover it with organic compost and garden soil.

Water the newly planted rhubarb crown thoroughly and maintain consistently moist soil throughout the growing season. Lay down a thick mulch layer to protect the soil surface, suppress weed growth, and retain moisture.

Did you know that there are 60+ distinct rhubarb cultivars? Although most have red stalks, there are also green and speckled types of rhubarb. Here are some of the most popular rhubarb varieties to grow in your garden at home.

Top Rhubarb Varieties for Home Gardeners

• Canada Red (Hybrid, retains deep red color when cooked, extra sweet flavor, heat-tolerant, 2-3′ tall, 3-4′ wide, USDA zones 3-9)
• Crimson Cherry (Hybrid, brilliant red stringless stalks, reliably cold-hardy, 4-5′ tall and wide, USDA zones 3-7)
• MacDonald (Hybrid, tender red stalks, fast-growing, resistant to root rot and wilt diseases, 2-3′ tall and wide, USDA zones 4-8)
• Raspberry Red (Hybrid, deep red stalks, early harvest, extra sweet flavor, 2-3′ tall, 3-4′ wide, USDA zones 3-8)
• Turkish (Heirloom, green stalks with red-tinged leaves, mild flavor, 2-3′ tall and wide, USDA zones 6-9)
• Valentine (Hybrid, early harvest of dark red stalks, sweet flavor with low acidity, cold-hardy and heat-tolerant, 2-3′ tall, 3-4′ wide, USDA zones 4-9)
• Victoria (Heirloom, bright red stalks grow up to 2 feet long, sweetly mild flavor, vigorous growth habit, 3-4′ tall and wide, USDA zones 3-8)

How Long Does Growing Rhubarb Take?

Growing rhubarb takes a bit of patience. To allow your plant to become well-established, don’t cut any rhubarb stalks during the first year after planting, and harvest sparingly in the second growing season. Rhubarb plants reach full maturity in their third year.

If you started your rhubarb from seed, you probably won’t be able to harvest any stalks until the second or third year. In most climates, growers start rhubarb seeds indoors in late winter for transplanting in early to late spring.

Rhubarb seeds typically take one to two weeks to germinate. Keep the seedlings indoors for eight to ten weeks, then transplant them outdoors when daytime temperatures are consistently above 45°F and the nights stay above freezing. It’s helpful to gradually harden off the young plants by exposing them to the elements progressively longer periods over a week or two before transplanting.

Ideal Growing Conditions for Rhubarb Plants

Rhubarb plants flourish in soil that’s well-draining and rich in organic matter, with a mildly acidic pH level (6.0-6.8). The plants grow fastest in full sun with five or more hours of direct sunlight each day. However, they do benefit from getting afternoon shade in warmer climates.

While rhubarb plants are exceptionally cold-hardy, most varieties don’t tolerate the heat very well. Rhubarb often gets cultivated as an annual winter vegetable in USDA zones 9 and higher.

In weather hotter than 90°F, rhubarb plants may start to bolt, prematurely producing flowers and seeds. Trim off any flower stalks as soon as you notice them. Doing so encourages the plant to direct its energy toward growing large, juicy leaf stalks.

In sandy or heavy clay soil, you’ll have better results by amending your garden beds with organic compost or manure. Or, try growing rhubarb in a raised bed. That way, you’ll ensure that the plants have nutrient-rich and well-draining soil so their deep root systems can thrive.

Avoid overcrowding your plants, as poor air circulation often leads to stunted growth, diminished harvests, root rot, and other plant diseases. Spacing between rhubarb plants should be at least four or five feet.

How To Divide Rhubarb Plants

Once they’re fully mature, dig up and divide your rhubarb plants every five to ten years while the root system is dormant. Doing so helps to keep them producing healthy new growth each year. You’ll know it’s time to divide your rhubarb when the plant seems to lose its vigor and begins producing smaller leaf stalks.

The best time to divide rhubarb depends on your growing climate. In regions with mild winters, dig up rhubarb crowns in late fall. If you get freezing winters, wait until early spring.

Dig deeply around your rhubarb plant four to six inches away from the crown’s center on all sides to loosen the surrounding soil. Carefully pry the root ball up, then bring it to a shaded location for division.

Each crown division must have at least two large buds. Use a clean, sharp shovel or gardening knife to cut the root ball into pieces. Replant them in another area or gift them to your green-thumbed family and friends.

Choosing the Best Rhubarb Fertilizer

In addition to providing nutrient-rich soil, it’s beneficial to fertilize your rhubarb plants regularly. They tend to be heavy feeders, and many gardeners choose to plant them near the compost pile so the plants have a constant supply of nutrients.

In most cases, feeding your rhubarb plants three times per year is plenty. Spread a half-cup of organic, all-purpose fertilizer around the base of each plant in early spring, mid-summer, and late autumn. It’s also beneficial to mulch with used coffee grounds and eggshells. They provide supplemental micronutrients and deter pests like rodents and slugs.

Growing Rhubarb in Containers

It’s also possible to grow rhubarb in pots. Choose a container that’s at least 24 inches deep and wide. Make sure it has several drainage holes so water doesn’t pool up at the bottom and cause root rot.

Fill your rhubarb container with high-quality potting mix up to an inch or two below the pot’s rim. Look for a soil blend with added perlite for drainage, compost or fertilizer for nutrients, and coconut coir or peat most for moisture retention. Plant your rhubarb crown according to the instructions described above.

Container-grown plants tend to go through fertilizer and water quickly. Check the moisture level regularly and water whenever the top several inches are completely dry. Nutrients leach out as water drains from the soil, so give your plant granular fertilizer every six to eight weeks or liquid fertilizer every three to four weeks.

To overwinter your potted rhubarb, prune the leaf stalks to an inch or two above the soil level after they’ve entirely died back. Cover the surface with several inches of mulch and wrap the sides of the container in old blankets and towels, bubble wrap, or cardboard. Move your rhubarb pot next to the wall of your house to take advantage of the radiant heat.

Harvesting and Storing Homegrown Rhubarb

Begin harvesting rhubarb stalks in the second or third year after planting. Cut sparingly during your first harvest season to allow the plant to keep establishing a healthy root system. After that, harvest rhubarb for eight to ten weeks, from late spring to mid-summer.

Cut rhubarb stalks when they’re 12-18 inches long and at least 3/4-inch thick. If your plant produces thin, spindly stalks, it’s likely running low on nutrients and you shouldn’t harvest. Fertilize and add organic compost to your garden soil.

When harvesting rhubarb, firmly grasp the base of a leaf stalk and detach it from the main stem by twisting gently. If you encounter significant resistance, use a sterile, sharp pair of pruning shears to cut it. Then, remove the rest of the stalk, so it doesn’t rot. Ensure at least two large leaves remain intact when harvesting, so the plant has enough energy to keep growing.

Rhubarb stalks turn bitter and stringy when the summer heat arrives. Leave the plant to keep growing and storing energy for the following year after mid-summer.

Once the foliage dries out in late autumn, cut the stems to five or six inches above the soil level. Insulate the root system with a thick layer of mulch.

Store fresh rhubarb in the crisper drawer of your fridge for up to three or four weeks. Wrap the ends of the rhubarb stalks in a damp paper towel, then place them in aluminum foil or a perforated plastic bag. To extend its shelf life, freeze rhubarb for up to 12 months. Rhubarb can get frozen raw or cooked.

Solutions for Common Pest and Disease Issues

While rhubarb plants are generally low-maintenance, they sometimes suffer from common pest and disease problems. Healthy plants are far more resistant against attacks from pathogens and pests. Sufficient nutrients, light, and water is their best defense.

Rhubarb plants are sometimes prone to root diseases like crown rot. It’s caused by soil-borne fungi that infect emerging buds near the soil level. Untreated, the disease gradually spreads to the entire rhubarb crown, turning it black and mushy. Eventually, the primary roots become rotted and hollow.

If you manage to notice it early enough, you can treat the affected plant with an organic copper or sulfur fungicide. If the disease has advanced too far, remove the whole plant. The fungus can survive in the soil indefinitely, so it’s best to replant your rhubarb elsewhere. Avoid growing other susceptible crops like cucumbers, eggplants, melons, peppers, squash, and tomatoes in that area.

The most frequent rhubarb pests are slugs, snails, and the rhubarb curculio beetle. Also called a rhubarb weevil, curculio beetles have a long snout and are dark-colored with a yellow dusting on their backs. They bore holes in rhubarb stalks to lay their eggs. When they hatch, the larvae burrow deep into the plant tissue to feed, causing the stem to eventually wilt and die off.

The only direct control for rhubarb curculio beetles is hand-picking the insects off, as they’re resistant to most insecticides. Remove their wild host plants from your property. These include dock, sunflower, and thistle.

Mulch with eggshells and coffee grounds to deter snails and slugs. They won’t crawl over the rough texture.

Rhubarb Companion Plants

Companion planting is a time-tested garden strategy that utilizes the naturally beneficial interactions between certain plants. Some attract pollinators and predators, while others repel harmful pests.

Moreover, some plant pairings reportedly improve their neighbors’ overall vigor and flavor when planted nearby. However, not all plants get along well, and some must live separately.

Thanks to their pungent odor, allium plants like chives, garlic, and onions are exceptional pest-repellants. They ward off aphids, cutworms, leaf beetles, slugs, spider mites, weevils, deer, and rodents.

Brassicas like broccoli, cabbage, and kale also make good companions for rhubarb. They help deter whiteflies and have similar needs regarding light, nutrients, temperature, and water.

Legume plants like beans and peas have a unique relationship with certain soil bacteria that allows them to fix nitrogen into the surrounding soil. They make outstanding companion plants for leafy vegetables like cabbage, Swiss chard, lettuce, rhubarb, and spinach. However, keep them away from your Alliums. These two plant groups reportedly stunt one another’s growth.

Avoid planting cucumbers, melons, squash, and tomatoes near rhubarb. They’re all heavy feeders and will compete with one another for nutrients.

Growing rhubarb in your veggie garden at home is a straightforward and satisfying endeavor. All that’s required is rich soil with good drainage, full sun, and consistent moisture. These easy-to-grow perennial vegetables reward your efforts with sweetly tangy rhubarb stalks year after year once they become well-established. In USDA zones 9 and up, grow rhubarb as a winter annual.

Do you have any questions or suggestions about how to grow rhubarb? Please share them in the comments! If you found these tips on growing rhubarb helpful, please share them with your fellow gardeners.