Rhubarb is a hardy perennial, botanically a vegetable but commonly used as a fruit, that can provide consistent harvests for a decade or more once successfully established. This long-lived plant, known for its tart stalks, requires little maintenance after its first few years of growth, making it a rewarding addition to many gardens. The key to ensuring its longevity and productivity lies in selecting the correct planting material and timing the initial placement precisely.
Optimal Planting Times
The ideal time to plant rhubarb is early spring or fall. Early spring planting is often preferred, as it allows the plant to set roots before the summer heat arrives. Crowns should be placed in the ground as soon as the soil is workable, typically when the soil temperature reaches a minimum of 50°F, while the roots are still dormant or just beginning to leaf out.
Fall planting should occur about six weeks before the first hard frost is expected in your region. This timing allows the root system to develop in the cooling soil before winter dormancy. Planting in the fall is beneficial in regions with hot summers, as it avoids immediate heat stress. Rhubarb thrives best in climates that experience winter temperatures below 40°F, which is necessary to break dormancy and stimulate spring growth.
Choosing Planting Material
Rhubarb can be started from dormant crowns (root divisions) or from seed, though crowns are the most common choice. A crown is an offset cut from a vigorous parent plant, typically featuring a piece of root with at least one visible dormant bud, or “eye.” Planting crowns leads to much faster establishment and allows for a quicker, though still delayed, first harvest, usually in the second year.
Crowns are genetically identical to the parent plant, meaning the resulting rhubarb will be true to the variety chosen, such as ‘Valentine’ or ‘Victoria.’ Starting rhubarb from seed is possible but is a slower process, often requiring an extra year of development before harvest. Seed-grown plants tend to be inconsistent in quality and may not retain the characteristics of the desired cultivar.
Site Selection and Soil Preparation
Selecting the proper location is important because rhubarb is a perennial that dislikes being moved once established. Rhubarb requires full sun, though it tolerates light afternoon shade in hot climates. Adequate spacing is necessary, as a single plant can grow to be three feet wide and tall, so crowns should be spaced 2 to 4 feet apart to prevent overcrowding.
The soil must be fertile and well-drained, as the roots are susceptible to rot if they sit in waterlogged conditions. Rhubarb is a heavy feeder, meaning the soil should be generously amended with organic matter like well-rotted manure or compost before planting. While some sources indicate rhubarb is not sensitive to soil pH, it generally performs best in a slightly acidic to neutral range, ideally between 5.8 and 7.0.
Establishing the Plant and Delaying Harvest
Once the crown is planted, with the bud approximately one to two inches below the soil surface, immediate deep watering is necessary to help the soil settle around the roots. Apply a layer of mulch, such as straw or shredded leaves, around the base of the plant, being careful not to bury the crown itself. Mulching suppresses weeds and assists in retaining consistent soil moisture, which benefits the developing root system.
The most important step for long-term plant health is delaying the harvest for the first year after planting, and ideally, only taking a minimal harvest in the second year. This restraint allows the plant to focus its energy on developing a strong, deep root system and building up energy reserves in the crown. Harvesting stalks too soon would remove the necessary leaves that perform photosynthesis, weakening the young plant’s vigor and long-term productivity. If a seed stalk appears during the first year, it should be promptly cut off at the base to redirect the plant’s energy back into root and stalk production.