If you’re wondering how to grow rhubarb in the south, you are not alone. Growing rhubarb in southern climates presents unique challenges, primarily managing its need for a significant winter chill. Many southern gardeners are told it’s impossible, but with the right strategies, you can enjoy a harvest of those tart, colorful stalks.
This guide provides clear, step-by-step methods adapted for warmer regions. We will cover variety selection, planting techniques, and seasonal care to trick this cold-loving perennial into thriving.
Success is about working with your local conditions, not against them. Let’s get started.
How To Grow Rhubarb In The South
Growing rhubarb successfully in the south requires a fundamental shift in approach. In its traditional northern range, rhubarb is a long-lived perennial that benefits from deep winter freezes. In the south, we must simulate those conditions and manage the intense summer heat. The core strategy involves three pillars: selecting ultra-heat-tolerant varieties, manipulating the planting and chilling cycle, and providing meticulous summer care. Think of it as creating a microclimate and annual rhythm that convinces the rhubarb plant it’s living farther north.
Understanding Rhubarbs Climate Needs
Rhubarb (Rheum rhabarbarum) is native to Siberia, which tells you a lot about its preferences. It requires a period of winter dormancy triggered by temperatures below 40°F. This “chill period” allows the plant to rest and store energy for spring growth. Without it, plants become weak, produce poorly, and often die.
Southern winters are often too brief or mild to provide adequate chilling. Furthermore, southern summers bring high heat and humidity that can stress or crown rot the plant. Your goal is to maximize chill exposure and minimize heat stress.
The Critical Chill Hour Requirement
Most rhubarb varieties need between 500 and 1000 hours below 40°F. In the Upper South (USDA zones 6-7), this may occur naturally some years. In the Middle and Lower South (zones 8 and above), it rarely happens. This is the primary barrier we must overcome through technique.
Choosing The Right Rhubarb Varieties For Southern Gardens
Not all rhubarb is created equal, especially for southern heat. Your variety choice is the most critical decision you will make. Opt for varieties known for better heat and disease tolerance. The classic red-stalked varieties often struggle, so focus on these better-adapted types.
- Victoria: A green-and-pink speckled variety known for being more heat-tolerant and vigorous than many red types. It’s a reliable producer in warmer areas.
- Canada Red and Crimson Red: Among the red varieties, these are often noted for having slightly better heat tolerance, though they still require careful chill management.
- MacDonald: A Canadian variety praised for its vigor and ability to withstand variable conditions better than some.
- Local Heirlooms: Seek out gardeners or nurseries in your area who have successfully grown rhubarb for generations. They may have a locally adapted strain.
Avoid forcing varieties like ‘Cherry Red’ for main garden crops, as they are often more demanding. Always purchase dormant crowns (root divisions) from reputable nurseries in the fall for best selection.
Pre-Planting Preparation: The Southern Strategy
In the north, rhubarb is planted in early spring. In the south, we flip the calendar to leverage the cooler part of the year.
Optimal Planting Time
Plant rhubarb crowns in the late fall or early winter. This timing is crucial. Planting in, say, October or November allows the crown to establish its root system in cool soil. It then experiences whatever natural winter chill your area provides right when it needs it. This sets the stage for spring growth.
Site Selection And Soil Preparation
Rhubarb demands perfect drainage, especially in humid southern climates. Crown rot is a leading cause of failure.
- Sun Exposure: Choose a site with full morning sun but afternoon shade. The intense southern afternoon sun will scorch and stress the plants. Dappled afternoon light or shade from a structure or tree is ideal.
- Soil Type: Rhubarb prefers fertile, loamy soil. Amend native clay or sandy soil heavily.
- Raised Beds Are Best: For almost all southern gardeners, planting in a raised bed (at least 12 inches deep) is the single best way to ensure the drainage rhubarb craves. It also allows for easier soil temperature and composition control.
- Soil Amendments: Work in 3-4 inches of well-rotted compost or aged manure into the planting area. Add a balanced, slow-release organic fertilizer according to package directions. Aim for a slightly acidic to neutral pH (6.0-7.0).
The Step-By-Step Planting Process
Proper planting technique gives your rhubarb the best start.
- Dig the Hole: In your prepared bed, dig a hole wide and deep enough to accommodate the crown’s roots without bending them.
- Position the Crown: Place the crown in the hole with the growth buds (the “eyes” or pink nubs) facing upward. The top of the crown should be 1-2 inches below the soil surface in northern climates, but in the south, plant it slightly shallower, about 1 inch below, to help prevent rot.
- Backfill and Water: Gently backfill the hole, firming the soil around the roots. Water thoroughly to settle the soil and eliminate air pockets.
- Spacing: Space crowns 3 to 4 feet apart. Rhubarb needs excellent air circulation to combat fungal diseases prevalent in humid summers.
- Mulch: Apply a 2-3 inch layer of light, organic mulch (like straw or pine bark) around, but not directly on top of, the crown. This conserves moisture and moderates soil temperature.
Annual Care And Maintenance Calendar
Caring for southern rhubarb is a year-round commitment with specific seasonal tasks.
Winter Care (Dormancy Period)
This is when we address the chill requirement. If your winter is mild (zones 8b-9), you may need to artificially chill crowns.
- Natural Chill: In zones 6-7a, mulch heavily after the ground freezes to maintain consistent cold.
- Artificial Chill (Pot Method): For very warm zones, a reliable tactic is to grow rhubarb as an annual from pre-chilled crowns. In late fall, plant crowns in large pots. Place the pots in a refrigerator (not freezer) for 8-10 weeks, keeping the soil barely moist. After chilling, move pots to a sheltered outdoor location or plant in the garden in late winter.
Spring Care (Growth And Harvest)
As temperatures warm, growth begins.
- Fertilize: As soon as you see new growth, side-dress plants with compost or a balanced organic fertilizer.
- Watering: Provide 1 inch of water per week if rainfall is insufficient.
- Harvesting:
This is the most important rule: Do not harvest any stalks in the first year. In the second year, harvest lightly for 2-4 weeks. Only from the third year onward can you harvest for 8-10 weeks, stopping by mid-June. Always harvest by twisting and pulling stalks from the base; do not cut them. Never remove more than one-third to one-half of the plant’s stalks at one time. Leave the leaves on the plant; they are toxic but are crucial for photosynthesis.
Summer Care (Heat Management)
This is the survival phase. The goal is to help the plant endure the heat.
- Cease Harvesting: Stop all harvest by early summer to allow the plant to rebuild strength.
- Ensure Afternoon Shade: If not already in place, use shade cloth to protect plants from intense afternoon sun.
- Water Deeply: Water at the base of the plant, not the leaves, to prevent rot. Deep, infrequent watering is better than frequent sprinkles.
- Mulch Heavily: Refresh mulch to keep roots cool and conserve soil moisture.
- Remove Flower Stalks: Immediately cut off any seed stalks that appear; they drain energy from the plant.
Fall Care (Preparation For Dormancy)
As temperatures cool, the plant will begin to die back naturally.
- After the first frost, cut back any remaining dead foliage to the ground.
- Clear away old mulch and debris to deter pests and disease.
- Apply a fresh layer of compost around the plant to nourish the crown over winter.
- In very warm areas, this is the time to dig and chill pots for the artificial chill method if you are using it.
Common Pests And Diseases In Southern Climates
Vigilance is key. Southern humidity fosters certain problems.
Diseases
- Crown and Root Rot: The number one enemy. Prevent it with perfect drainage, avoiding crown waterlogging, and proper spacing for air flow.
- Leaf Spot Fungi: Appear as spots on leaves. Remove affected leaves, improve air circulation, and avoid overhead watering.
Pests
- Slugs and Snails: They love rhubarb’s large leaves. Use organic baits, traps, or diatomaceous earth.
- Two-Spotted Spider Mites: Thrive in hot, dry conditions. Look for stippling on leaves. Blast with water or use horticultural oil.
- Rhubarb Curculio: A beetle that bores into stalks. Hand-pick and destroy affected stalks and insects.
Long-Term Success And Division
Even with perfect care, rhubarb in the south is often shorter-lived than in the north. It may peak for 3-5 years before declining. Division can rejuvenate it.
Divide crowns in late fall or early winter when dormant. Dig up the entire clump and use a sharp spade to cut it into sections, each with at least one large bud and a portion of roots. Replant the healthiest divisions immediately and discard the old, woody center. This is also how you propagate your successful plants.
Growing Rhubarb In Containers
For many in the Deep South, growing rhubarb in a large container is the most effective method. It allows for complete control over soil, drainage, and chill manipulation.
- Use a pot at least 20 inches deep and wide with excellent drainage holes.
- Fill with a high-quality, well-draining potting mix amended with compost.
- Follow the same planting depth and care instructions.
- You can easily move the pot to a refrigerator for chilling or to shadier spots as seasons change.
Frequently Asked Questions
Can rhubarb grow in hot climates like Florida or Texas?
It is very challenging but possible with the “annual pot chill” method. Gardeners in zones 9-10 treat rhubarb as a winter annual, chilling crowns artificially in a refrigerator before planting in late fall for a winter/spring harvest before the extreme heat arrives.
Why are my rhubarb stalks thin and spindly?
Thin stalks usually indicate insufficient chilling, overcrowding, lack of nutrients, or harvesting too heavily or too early in the plant’s life. Ensure the plant gets its required chill period and fertilize adequately in spring.
Is it safe to eat rhubarb leaves?
No. Rhubarb leaves contain high levels of oxalic acid and other compounds that are toxic if ingested. Always cut the leaf blade from the stalk immediately after harvesting and compost the leaves. Only the stalks are edible.
How do I protect my rhubarb from a late spring frost?
Rhubarb is quite cold-hardy, and emerging growth can tolerate a light frost. If a hard freeze is expected after growth has started, you can cover the plants with a frost cloth or bucket overnight. Uncover during the day.
What is the best fertilizer for rhubarb in the south?
A balanced, slow-release organic fertilizer (like a 10-10-10 formula) or well-rotted manure applied in early spring is ideal. Avoid high-nitrogen fertilizers later in the season, as they can promote soft growth susceptible to disease and reduce stalk quality.
Growing rhubarb in the south is an exercise in patience and adaptation. It requires accepting that the plant’s lifecycle may be different here—perhaps treating it more like a cherished biennial than a permanent perennial. By focusing on variety, planting time, drainage, and heat management, you can defy the odds. The reward of pulling your own crisp, tart stalks for a pie or sauce is well worth the extra effort. Start with a single, well-chosen crown this fall, apply these principles, and you’ll be on your way to a southern rhubarb harvest.