Rhubarb

Plant Overview

Rhubarb (Rheum × hybridum) is listed in the Polygonaceae family and categorized as a vegetable with a perennial life cycle. This profile summarizes growing information for hardiness, light, soil, water, seed starting, maturity, and other available cultivation details. Difficulty is listed as Easy.

Plant ID

PLT-0051

Family

Polygonaceae

Plant type

Vegetable

Life cycle

Perennial

Growth habit

Clump-forming herbaceous perennial grown for its thick edible leafstalks

Mature height

Leafy growth commonly reaches about 2-3 feet; size varies by cultivar and growing conditions

Mature spread

Variety-dependent; vigorous established leafy clumps can reach 5 feet across or more, while compact varieties remain smaller

Difficulty

Easy

Growing Conditions

Rhubarb is listed for full sun conditions. Water needs are listed as moderate; keep evenly moist without waterlogging. The database soil reference is Fertile, well-drained soil with organic matter. The listed soil pH range is 6.0-7.0, and the listed hardiness range is 3-8.

Hardiness zones

3-8

Sunlight

Full sun

Soil

Fertile, well-drained soil with organic matter

Soil pH

6.0-7.0

Water needs

Moderate; keep evenly moist without waterlogging

Plant spacing

Space plants 36-48 inches apart in rows 3-4 feet apart

Seed & Germination

For propagation, the database note is seed may take up to about two weeks to germinate under suitable conditions; this does not apply to crown divisions. Planting-depth guidance: Lightly cover seed with potting mix when starting indoors. Maturity guidance: For perennial plantings, do not harvest during the first year. Harvest lightly in the second year, with a full harvest season generally beginning in the third year; seed-grown plants may take longer. Use these values as general reference points and adjust for local climate, seed source, and growing conditions.

Germination

Seed may take up to about two weeks to germinate under suitable conditions; this does not apply to crown divisions

Germination temperature

About 60-75 F is a suitable soil temperature range for seed germination

Seed depth

Lightly cover seed with potting mix when starting indoors

Sowing method

Establish perennial beds from dormant crown divisions in early spring, or raise seedlings for later transplanting

Start indoors

When growing from seed, start indoors about six weeks before the last frost; crown divisions do not require indoor seed starting

Transplanting

Plant dormant crown divisions in early spring with the crown bud about 2 inches below the soil surface; use a well-drained site to reduce crown rot

Harvest & Propagation

Days to maturity

For perennial plantings, do not harvest during the first year. Harvest lightly in the second year, with a full harvest season generally beginning in the third year; seed-grown plants may take longer

Harvest

Pull mature leafstalks from established plants and remove the leaf blades. Take no more than about one-third of the stalks at a time, leaving foliage to replenish the roots. Do not eat the leaf blades

Propagation

Usually propagated by dividing healthy dormant crowns, retaining at least one strong bud on each division; seed propagation is possible but plants take longer to reach full harvest

Seed saving

To preserve a named variety, divide healthy crowns rather than relying on saved seed. Seed-grown offspring may differ substantially from the parent. For stalk production, remove flower stalks so the plant directs more energy into vegetative growth

Pollination

Cross-pollinated when grown for seed; seedlings can differ substantially from the parent plant. Pollination is not needed for leafstalk harvest

Garden Information

Common pests

Usually has few insect problems; rhubarb curculio and stalk borers can damage stalks and crowns

Common diseases

Root and crown rots in wet or poorly drained soil; Ascochyta and Ramularia leaf spots can affect foliage

Uses

Tart edible leafstalks used in pies, tarts, and sauces; leaf blades are poisonous and must not be eaten