Rhubarb
Also known as
Garden rhubarb, Pie plant, Edible rhubarb
Keep this plant’s care guide close at hand.
Get the appAbout Rhubarb
Rheum rhabarbarum, commonly known as garden rhubarb, is a long-lived, cold-hardy herbaceous perennial cultivated for its tart, fleshy leaf stalks. It forms large clumps of broad, triangular to heart-shaped leaves borne on thick red to green petioles, while the leaf blades themselves contain high levels of oxalates and should not be eaten. Emerging early in spring from a woody crown, rhubarb drives vigorous vegetative growth in cool weather and may send up tall, airy panicles of small greenish-white flowers if not deadheaded. Plants prefer deep, humus-rich, well-drained soil and consistent moisture, producing best in climates with cold winters that satisfy their chilling requirement. Mature clumps can span 1–1.5 m across and are typically divided every few years to maintain vigor. In hot summers, growth slows or the plant may go semi-dormant, resuming with cooler temperatures. Rhubarb is widely used in pies, compotes, and preserves, prized for its bright acidity and color.
Taxonomy
Properties & Requirements
How to care for Rhubarb
Water
Keep soil consistently moist but never waterlogged. Provide roughly 1–1.5 inches (25–40 mm) of water per week, including rainfall, during active spring growth and harvest. Water deeply and infrequently to encourage robust roots, allowing the top 2–3 cm of soil to dry slightly between waterings. Mulch reduces evaporation and moderates swings. In hot climates or containers, increase frequency as media dries faster. Reduce watering as plants slow in midsummer heat and during dormancy, resuming regular moisture in fall.
Light
Full sun is ideal in cool-summer regions: 6–8+ hours of direct light promotes thick, flavorful stalks and reduces disease. In hotter climates, give morning sun with light afternoon shade to prevent stress and premature bolting. Too much shade (fewer than 4–5 hours) yields spindly petioles and poor production. Maintain open spacing and remove weeds to improve air flow and leaf drying, which helps limit foliar diseases such as leaf spot and powdery mildew.
Nutrients
Rhubarb is a heavy feeder. In late fall or very early spring, work in 5–8 cm of finished compost or well-rotted manure around, not on, the crown. At emergence, side-dress with a balanced, slow-release fertilizer (e.g., 10-10-10) and repeat lightly after the main harvest if growth flags. Avoid high nitrogen late in the season, which encourages soft, frost-tender growth. Maintain a 5–8 cm organic mulch to conserve moisture and steadily feed soil biology.
Temperature
Best in cool climates (USDA Zones 3–7/8). Rhubarb requires winter chilling to reset buds and maximize yield, with crowns tolerating deep freezes below -20 F (-29 C) under mulch. Optimal growth occurs between 50–70 F (10–21 C). Prolonged heat above 85 F (29 C) can stall growth or trigger bolting; provide afternoon shade and extra mulch in warm regions. Avoid waterlogged soils in cold snaps, which can rot crowns. Do not harvest in the first season to build reserves.
