If you’re planning a rhubarb patch, one of the first questions you might ask is, how tall does rhubarb grow? This perennial vegetable is known for its large, dramatic leaves and edible stalks, and it can reach impressive heights under the right conditions. Understanding its potential size helps you plan your garden space effectively.
In general, a mature, healthy rhubarb plant will send up flower stalks and leaf stalks that can stand 2 to 3 feet tall. The entire plant, including its massive leaves, can spread out to cover a diameter of 3 to 4 feet. However, with ideal care and perfect growing conditions, some varieties can grow even taller, creating a real focal point in your garden.
How Tall Does Rhubarb Grow
This is the core question. The height of your rhubarb depends on several key factors: the specific variety you plant, the quality of your soil, the amount of sunlight it receives, and how well you maintain it. Most standard garden rhubarb plants, like the popular ‘Victoria’ or ‘Canada Red’, typically produce stalks that are 12 to 18 inches long for harvesting. But the plant itself, with its leaves fully unfurled, will be taller.
When you include the flower stalks (which you should usually remove), the plant can easily reach 3 feet or more in height. It’s a substantial plant that needs room to thrive.
Factors That Influence Rhubarb Height
Not all rhubarb plants will grow to the same size. Here are the main elements that determine how tall and large your plant will become.
1. Variety and Genetics
Just like people, plants have genetic blueprints. Some rhubarb cultivars are simply bred to be larger.
- ‘Victoria’: A very common green and pink variety, it’s vigorous and can produce tall, thick stalks, often reaching the upper end of the height range.
- ‘Canada Red’ or ‘Crimson Red’: Known for its deep red stalks, it might be slightly more compact in overall leaf spread but still produces stalks of excellent length.
- ‘German Wine’: A older, robust variety known for its very thick, green stalks and large plant size. It can be a real giant in the garden.
2. Sunlight and Location
Rhubarb performs best in full sun, meaning at least 6-8 hours of direct sunlight daily. A plant in full sun will grow more vigorously, produce thicker stalks, and achieve a more impressive height compared to one struggling in partial shade. More sunlight equals more energy for growth.
3. Soil Quality and Nutrition
Rhubarb is a heavy feeder. It prefers deeply dug, well-draining soil that is rich in organic matter. Poor, sandy, or compacted soil will stunt its growth. To reach its full height potential, the soil must provide ample nutrients.
- Before planting, incorporate plenty of compost or well-rotted manure into the bed.
- An annual application of a balanced fertilizer or more compost in early spring supports strong growth.
- Soil pH should be slightly acidic to neutral (around 6.0 to 6.8).
4. Watering and Moisture
Consistent moisture is crucial, especially during the main growing season in spring and early summer. While rhubarb is somewhat drought-tolerant, a lack of water will result in smaller, thinner stalks and a shorter overall plant. Aim for about 1 inch of water per week, either from rainfall or your hose.
How to Maximize Your Rhubarb’s Growth
If you want your rhubarb to reach those impressive heights, follow these practical steps. They are simple but make a huge difference.
Step 1: Planting for Success
Start right. Plant rhubarb crowns or divisions in early spring or fall. Dig a wide, deep hole and mix the native soil with compost. Set the crown so the buds are just 1-2 inches below the soil surface. Space plants at least 3 feet apart to give them room to expand. Crowding will limit their size.
Step 2: The Feeding Schedule
Feed your plant twice a year for best results.
- Early Spring: As soon as you see the first pink buds poking through the soil, apply a handful of a balanced organic fertilizer or a shovelful of compost around the base of the plant. Work it gently into the soil surface.
- After Harvest: Once you stop pulling stalks (usually around mid-summer), give the plant another light feeding to help it recover and store energy for next year.
Step 3: Smart Watering and Mulching
Water deeply at the base of the plant rather than sprinkling the leaves. This encourages deep root growth. Applying a 2-3 inch layer of organic mulch (like straw or shredded leaves) around the plant helps retain soil moisture, suppresses weeds, and adds nutrients as it breaks down. This creates the consistent, cool root environment rhubarb loves.
Step 4: Proper Harvesting and Maintenance
How you harvest directly impacts the plant’s health and future size.
- Don’t harvest the first year: Allow a new plant to establish its root system fully.
- Harvest lightly in the second year: Take only a few of the largest stalks.
- Harvest mature plants properly: Grasp a stalk at its base, twist gently, and pull sideways. Never cut the stalks, as this can leave a stump that rots. Always leave at least one-third of the stalks on the plant to keep it producing energy.
- Remove flower stalks: As soon as you see a central flower stalk (seed head) start to emerge, cut it off at the base. Letting the plant go to seed wastes a tremendous amount of energy that could be used for growing taller and producing thicker leaf stalks.
When Size Becomes a Problem
Sometimes, rhubarb can grow almost too well. If a plant becomes too large for its space, or if the center of the clump starts to die out and produce only thin stalks, it’s a sign it needs dividing. This is typically done every 5-8 years in early spring. Dig up the entire clump, use a sharp spade to cut it into several smaller pieces (each with at least one strong bud), and replant them with plenty of space and fresh compost.
FAQ About Rhubarb Growth
Q: What is the tallest rhubarb can grow?
A: In exceptional conditions, with perfect soil and climate, some rhubarb plants can have leaf stalks over 2 feet long and flower stalks pushing 4 feet tall. The giant leaves themself can add another foot of height.
Q: Why is my rhubarb not growing tall?
A: Short, thin stalks are usually a sign of problems. Common causes include: harvesting too heavily or too early in the plant’s life, inadequate sunlight, poor/nutrient-deficient soil, lack of water, or the plant being too old and needing division.
Q: Does rhubarb get bigger every year?
A: Yes, a rhubarb plant will increase in size each year as its root crown expands. It reaches full maturity and its maximum potential height at about 5-6 years old, provided its cared for properly.
Q: Should I let my rhubarb flower?
A: It’s generally not recommended. The flowering process diverts energy from stalk production, which can result in shorter, thinner edible stalks the following year. It’s best to remove the flower stalk as soon as you notice it.
Q: How much space does a rhubarb plant need?
A: Plan for a final footprint of about 3 to 4 square feet per plant. Always space crowns or plants at least 3 feet apart when planting to ensure they have enough room to reach their full height and spread without competition.
Growing rhubarb is a rewarding long-term garden project. By providing rich soil, consistent moisture, and proper care, you can encourage your plants to reach their full, impressive heights. Remember to be patient, especially in the first two years, and your reward will be a robust plant that provides a bountiful harvest of tall, crisp stalks for many springs to come.