Rhubarb is a perennial vegetable cherished for its tart, ruby or green stems. Known for its ease of care, it thrives in cooler climates and can remain productive for over a decade. Popular varieties include 'Canada Red' and 'Victoria'. While growing rhubarb is straightforward, it requires well-draining soil and consistent moisture, especially during hot summers.
- Common Names: Pie Plant
- Scientific Name: Rheum rhabarbarum
- Plant Type: Herbaceous perennial
- Plant Height: 2-3 feet
- Growing Difficulty: Easy
- Growing Time: Three years to harvest
- Temperature: Below 75°F in summer
- Hardiness Zone: 3 to 8 (Find your hardiness zone here)
- Sunlight: Full Sun
- Soil pH: 6.0 to 7.0
- Watering Frequency: Water well and consistently
- Plant Spacing: Space plants 2-4 feet apart
Different Methods to Grow Rhubarb
Growing from Crowns
This method involves planting rhubarb crowns, which are sections of the plant's root system. Crowns are typically planted in early spring or late fall, spaced 2-4 feet apart, with buds facing up.
- Pros: Faster harvest, more reliable plant characteristics.
- Cons: More expensive, limited availability of crowns.
Growing from Seeds
Starting rhubarb from seeds is a cost-effective method but requires patience. Seeds are sown indoors in early spring and transplanted outside after the last frost, with a waiting period of about three years before the first harvest.
- Pros: Cost-effective, easy to start.
- Cons: Longer waiting period (three years), potential variability in plant characteristics.
Dividing Established Plants
Dividing established rhubarb plants every 3-4 years helps maintain plant health and productivity. This involves digging up the plant, splitting the root system, and replanting the divisions.
- Pros: Promotes healthy growth, rejuvenates older plants.
- Cons: Labor-intensive, requires established plants.
Ideal Soil and Location Requirements
Rhubarb thrives in well-draining, fertile soil enriched with organic matter like compost or well-rotted manure. It prefers a sunny location but can tolerate partial shade, especially in hotter climates. Ensure the site has good drainage to prevent root rot.
When to Plant Rhubarb
Rhubarb is best planted in late fall or early spring. In fall, plant crowns after dormancy sets in, while in spring, plant when the soil is workable and before growth begins. Ensure soil temperatures are at least 50°F. Check local frost dates to determine the optimal planting time.
Growing Rhubarb Outdoors
Planting 1-year-old rhubarb crowns is the best method for growing rhubarb outdoors in a garden. This method is the easiest because it ensures a higher success rate and quicker harvest compared to growing from seeds. Here’s a step-by-step guide for home gardeners:
- Site Selection. Choose a site with full sun or partial shade and well-draining, fertile soil.
- Soil Preparation. Mix compost, rotted manure, or other organic matter into the soil.
- Planting Time. Plant in late fall or early spring when the soil is workable and before growth begins.
- Planting Crowns. Eliminate perennial weeds. Dig large holes. Space plants 2 to 4 feet apart and rows 3 to 4 feet apart. Plant crowns with eyes about 2 inches below the soil surface. Water well at planting time.
- Mulching. Mulch with a heavy layer of straw to retain moisture and discourage weeds.
- Watering. Water consistently, especially during hot, dry periods.
- Seed Stalk Removal. Remove seed stalks to focus energy on stalk production.
- Fertilizing. Apply a light sprinkling of 10-10-10 fertilizer in early spring.
- Fall Maintenance. Remove plant debris in fall and cover with 2 to 4 inches of organic mulch.
Growing Rhubarb Indoors
Growing rhubarb indoors is not feasible due to its need for a dormancy period with temperatures below 40ºF (4°C) in winter and below 75ºF (24°C) in summer. However, for those who have the space and conditions to grow rhubarb outdoors, here is a step-by-step guide:
- Site Selection. Choose a site with full sun or partial shade and well-draining, fertile soil.
- Soil Preparation. Mix compost, rotted manure, or other organic matter into the soil.
- Planting Time. Plant in late fall or early spring when the soil is workable and before growth begins.
- Planting Crowns. Eliminate perennial weeds. Dig large holes. Space plants 2 to 4 feet apart and rows 3 to 4 feet apart. Plant crowns with eyes about 2 inches below the soil surface. Water well at planting time.
- Mulching. Mulch with a heavy layer of straw to retain moisture and discourage weeds.
- Watering. Water consistently, especially during hot, dry periods.
- Seed Stalk Removal. Remove seed stalks to focus energy on stalk production.
- Fertilizing. Apply a light sprinkling of 10-10-10 fertilizer in early spring.
- Fall Maintenance. Remove plant debris in fall and cover with 2 to 4 inches of organic mulch.
Rhubarb can produce a crop for up to 15 years once established, making it a long-term addition to any garden.
Caring for Rhubarb
- Watering: Rhubarb needs consistent moisture, especially during hot, dry periods. Water deeply and regularly to keep the soil evenly moist but not waterlogged.
- Mulching: Apply a thick layer of mulch, such as straw, around the base of the plants. This helps retain moisture, suppress weeds, and keep the soil cool.
- Pest Management: Watch out for common pests like slugs, snails, and rhubarb curculio. Handpick these pests and use barriers like copper collars to protect your plants. For fungal issues like gray mold, ensure good air circulation and avoid overhead watering.
- Fertilizing: Each spring, apply a balanced fertilizer, such as 10-10-10, to support healthy growth. Avoid fertilizing in the first year to prevent over-stimulation of young plants.
- Harvesting: Begin harvesting rhubarb stalks in the third year when they are 12 to 18 inches long. Twist and pull the stalks from the base rather than cutting them to avoid damaging the plant. Always leave at least two stalks per plant to ensure continued growth.
Common Challenges With Rhubarb
Rhubarb is a remarkably resilient plant, making it a favorite among gardeners. It's easy to grow, requiring minimal care once established. With its ability to thrive for over a decade, rhubarb is a long-term investment for any garden. It prefers cooler climates and needs a dormancy period to produce an abundance of stalks. In my experience, once you get the planting right, rhubarb practically takes care of itself, needing only consistent watering and occasional mulching.
However, growing rhubarb isn't without its challenges. Overcrowding can lead to subpar growth, so it's essential to divide the roots every few years. Rhubarb also dislikes soggy soil, which can cause root rot. Pests like slugs and snails, along with diseases such as gray mold, can occasionally be a problem. Removing seed stalks is crucial to prevent the plant from wasting energy. Despite these challenges, with a bit of attention, rhubarb can be a rewarding and low-maintenance addition to your garden.
Safety of Rhubarb for Pets
Rhubarb is toxic to cats, dogs, and other pets due to the presence of soluble calcium oxalates. If you suspect your pet has ingested rhubarb, contact the ASPCA 24-hour hotline immediately.
Frequently Asked Questions
Can rhubarb leaves be composted?
Yes, rhubarb leaves can be composted. Despite their toxicity to humans and pets, the oxalic acid in the leaves breaks down during the composting process, making them safe to use as compost in your garden.
How long does rhubarb grow?
Rhubarb is a perennial plant that can produce stalks for up to 15 years once established. With proper care, including regular watering, mulching, and occasional fertilizing, rhubarb can remain productive for over a decade.
Is it safe to harvest rhubarb stalks late in the year?
It is generally not recommended to harvest rhubarb stalks late in the year. Harvesting should be done in spring and early summer to avoid stressing the plant, allowing it to store energy for the next growing season.
Can you plant the seeds from a flowering rhubarb plant?
Yes, you can plant seeds from a flowering rhubarb plant. However, the resulting plants may not resemble the parent plant, as rhubarb seeds do not always come true to variety. Crown division is often preferred for consistent results.
