Part 2 in our Growing Rhubarb: A Guide for All Climates Series
A short series offering guidance on rhubarb, tips to grow it, and methods to grow it outside of its preferred range.
Although rhubarb prefers temperate environments, it can be grown outside its ideal temperature range with some care. With additional winter prep in colder climates and careful planning for summer in hot regions, rhubarb can thrive almost anywhere.
More so than in temperate climates, it’s vital to watch the weather. Extreme heat spells or cold snaps require forethought to protect your plants, and site selection is even more important. These tips cover key points for hot and cold climates, and how you can grow rhubarb successfully.
Rhubarb can grow in hot, dry climates such as Arizona, the high deserts of California, and parts of inland Australia, but it requires some adjustments to survive the intense summer heat while still receiving enough winter chill.
1. Timing and Seasonality Plant crowns in late fall (October–November) to take advantage of cooler temperatures and help roots establish. Light harvesting can begin in late winter to early spring, before the intense summer heat arrives. Once temperatures climb above about 85°F (29°C), rhubarb will naturally go dormant. Forcing it to grow during midsummer can stress the plant and reduce its lifespan.
2. Light and Shade Management Rhubarb thrives with morning sun and afternoon shade. In extremely hot areas, protect leaves from sun scorch using shade cloth, pergolas, or by planting near structures that block the afternoon sun. In containers, plants can be moved to shaded patios or under trees during peak heat; putting pots on wheels makes this easier.
3. Mulching and Soil Care Apply 3–4 inches of organic mulch around the crown to insulate roots, retain moisture, and reduce soil temperature. Mulch can lower soil temperature by around 10°F, keeping roots cooler in scorching summer heat.
4. Container Planting Options Deep pots (at least 2 ft wide by 2 ft deep) are highly effective. Containers allow you to relocate plants for shade, and the soil mix can be tailored for drainage and fertility. Container soil will need yearly replenishment with compost as hotter temperatures often lead to quicker nutrient leaching.
5. Summer Dormancy and Winter Chill During summer dormancy, rhubarb leaves usually wilt or die back entirely. Water lightly to keep the soil damp but not wet. In regions where winters remain warm (e.g., parts of inland Australia), potted rhubarb can be moved to a cool space around 40°F / 4–10°C for 6–8 weeks to simulate dormancy and trigger spring growth.
6. Watering Considerations Water deeply and regularly to encourage robust root growth, making sure to water below the leaves so it soaks into the soil. The soil should be damp but not soggy. Tools like Ollas can provide steady moisture and cool soil conditions, though they must be removed or protected during frost.
7. Wind Care Hot, desert winds can desiccate leaves quickly. If you live in a flatter, more open area, watch the winds and provide protection against the prevailing winds. Shade cloth fixed vertically is an excellent wind screen.
With careful management of light, mulch, water, and timing, rhubarb can thrive in hot, arid climates. Because rhubarb needs winter chill to survive as a perennial, plants in these regions may last 2–3 years rather than the usual 5+, which is normal. Using large pots gives flexibility to move plants to cooler spots during winter or summer.
In colder regions, rhubarb is extremely hardy, but extra protection ensures crowns survive harsh winters and produce strong harvests.
1. Mulching and Winter Cover After leaves die back in fall, apply a thick 4–6 inch layer of mulch around the crown to insulate against freezing temperatures. Straw, leaf litter, or compost works well. In very harsh winters (USDA Zone 4 or mountainous areas), cover crowns with burlap, a cloche, or even a large pot to protect young shoots from late frosts and snow. Mulch also helps prevent frost heaving, where crowns lift from the soil during freeze-thaw cycles.
2. Site Selection Choose a sunny location with well-draining soil. Cold air can settle in low spots, so slightly elevated planting sites help protect crowns from frost. Small mounds are ideal in frost-prone areas.
3. Forcing Rhubarb in Cold Climates Forcing is ideal for early spring harvests. Use the same mulch-and-cover method as in temperate climates, ensuring crowns have been established for at least 1–2 years. Darkness encourages tender, sweet stems for early desserts (more on harvesting and forcing in Part 3).
4. Watering Water sparingly during winter dormancy. Excess moisture combined with freezing temperatures can lead to crown rot. Resume watering in spring as soil thaws and growth begins, or observe soil moisture—sometimes no extra water is needed if rainfall is sufficient.
5. Longevity With proper winter protection, rhubarb crowns can live for 10–15 years or more. Dividing overcrowded crowns in late winter or early spring rejuvenates plants and maintains productivity.
Growing rhubarb in more extreme climates requires planning, but with attention to temperature, predicted rainfall, and seasonal adjustments, you can enjoy delicious stems year after year. Even if harvests are smaller or plants behave more like annuals in hot regions, foresight ensures your rhubarb thrives for seasons to come.
In Part 3, we’ll go over general care tips for all climates, harvesting advice, and additional ways to grow rhubarb.