Rhubarb
Rheum rhabarbarum. POLYGONACEAE.
Planting, Growing, and Harvesting Rhubarb
You’ll find everything you need to know to plant and grow rhubarb in the accompanying table’s tabs:
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- How many rhubarb plants to grow
- Growing conditions for rhubarb
- When to plant rhubarb
- How to plant rhubarb
- Watering, fertilizing, and pruning rhubarb
- Companion plantings for rhubarb
- How to harvest, store, and use rhubarb
Growing Rhubarb
Rhubarb is a cool-season perennial and edible-ornamental plant, to 3 ft. (90 cm) tall and wide, bearing broad leaves on edible fleshy stalks of green, red, and red-tinged to white, 10–15 in. (25–38 cm) long.
There are 60 to over 100 different varieties of rhubarb popularly grown around the world, and one or more grow in U.S.D.A. plant hardiness zones 2–9. Choose those cultivars known to be successful in your region.
Rhubarb’s stalks provide a tangy ingredient for making sauces, pies and condiments. Rhubarb may require up to 4 years before it produces a full harvest. Often grown as a garden ornamental for its attractive foliage.
Popular varieties include ‘Cherry Red’, ‘Chipman’s Canada Red’, ‘Granddad’s Favourite’, ‘Holstein Bloodred’, ‘Kangahru’, ‘Riverside Giant’, ‘Timperley Early’, ‘Turkish’, and ‘Victoria’.
Rhubarb Plant and Care Guide
How Much to Plant
Allow 2–3 plants per household member, yielding 4–6 lbs. (1.8–2.7 kg) of rhubarb stalks.
How to Plant
Seed germinates in 14–21 days; root divisions, 16–25 days.
Average Climates: Sow seed or plant root divisions in full sun–partial shade in early spring when soil warms to 40–85°F (5–29°C).
Mild-Winter Climates: Plant root divisions in autumn after summer heat has broken and 3–4 months of mild weather remain.
Set out root divisions 3–4 in. (75–100 mm) deep, 2–3 ft. (60–90 cm) apart, in mounded rows raised 6–8 in. (15–20 cm) tall and 18 in. (45 cm) wide, 4–6 ft. (1.2–1.8 m) apart.
Best Conditions for Growth
35–75°F (2–24°C). Best in mild, cool-summer climates. Shade plants in full sunlight at temperatures over 85°F (29°C). Harvest until dormancy in zones 5–9.
In cold-winter regions, zones 2-4, cease harvesting in July so that leaves may provide nutrients to the root crown and roots of the plants to help them survive long winter dormancy. Burying crowns and mulching over them in these zones helps prevent freeze-thaw cycles that otherwise would kill the plants.
Soil Type and Fertility
Moist, well-drained loam. Fertility: Rich. 5.0–6.8 pH. Prepare soil at least 30 in. (75 cm) deep.
Proper Care
Easy. Keep evenly moist. Fertilize at time of planting and after each harvest with 5–10–5 formula. Cultivate using care to avoid cutting the widespread, shallow roots.
In cold-winter climates, removing all dead stems and foliage to the crown in autumn after frost, mulch with 1–2 ft. (30–60 cm) of straw, and cover with 1–2 in. (25–50 mm) of soil; uncover in spring when soil is workable. In mild-winter climates, light mulching after foliage dies is sufficient to protect the root crown from frost damage.
Replant with new stock or by dividing root crowns after 4 harvests. Pest and disease resistant.
Pairing Recommendations
Artichokes, asparagus, and cole vegetables.
Maturity, Picking and Gathering
Requires 2–4 years for first full harvest. Cut stalks when stems reach 2 ft. (60 cm) long, thinning outer stalks and leaving the central growth bud and 4–6 leaves to resprout.
Allow new leaves to mature before cutting, about 4–6 weeks between harvests. Cease harvesting 4–6 weeks before first hard frost.
Cut and remove any flower stalks as they appear.
How to Store and Preserve
Fresh in vegetable keeper of refrigerator for 2–4 weeks; cut, blanched, and frozen, 3–4 months; processed as sauce or pie fillings and frozen, 1 year; processed and canned, 3 years. Chop tart, stringy rhubarb stalks into pieces 1–2 in. (25–50 mm) long, cover with water, boil, and add sugar to taste to make tangy sauce for hotcakes, waffles, and ice cream.
Warning: Foliage of rhubarb is fatally toxic if ingested. Avoid planting in areas frequented by children and pets.