Rhubarb (Rheum rhabarbarum) is botanically classified as a perennial vegetable, though it is primarily utilized in culinary applications as a fruit due to its tart stalks. Establishing a new rhubarb patch is most reliably achieved by planting dormant root divisions, commonly referred to as crowns. Crowns are fragments of the parent plant’s root system that contain the buds necessary for new growth. Starting with crowns ensures genetic consistency and significantly reduces the time required for a productive harvest compared to starting from seed. A well-sited and properly planted patch can remain productive for fifteen years or more.
Site Selection and Soil Preparation
The optimal time for planting rhubarb crowns is either in early spring, just as the ground thaws, or in late fall after the plants have gone dormant. Planting during these cooler periods minimizes transplant shock and allows the root system to establish itself before summer heat. Rhubarb thrives in locations receiving full sun (six or more hours of direct sunlight daily), though it can tolerate partial afternoon shade, especially in warmer climates.
Selecting a location with adequate space is important because mature rhubarb plants can spread three to four feet in diameter. Crowding inhibits proper air circulation and reduces vigor, requiring a minimum spacing of three to four feet between crowns. The planting site must have deep, rich, and well-draining soil, as rhubarb roots are susceptible to rot in saturated conditions.
Prior to planting, the soil should be generously amended with organic matter to enhance drainage and nutrient retention. Incorporating well-aged compost or fully decomposed manure several weeks before planting improves soil structure and provides the sustained fertility this heavy feeder requires. Digging the amendment deeply ensures the new roots have a nutrient-rich environment for expansion and long-term health.
Step-by-Step Planting of Rhubarb Crowns
Once the soil is prepared, carefully inspect the dormant rhubarb crown for the characteristic pink or reddish “eyes,” which are the growth buds. These buds are the points from which the leaf stalks will emerge, and their health is an indicator of the crown’s viability. If necessary, trim any damaged or overly long roots to encourage fresh root development after planting.
Dig a planting hole significantly wider than the crown’s root mass, allowing the roots to spread out naturally. The depth should ensure that when the crown is placed inside, the top of the eye buds rests precisely at or just slightly below the finished soil line. Deep planting can smother the buds, while planting too shallowly exposes the crown to drying out.
Place the crown in the center of the hole, ensuring the buds are oriented upward, and gently spread the fleshy roots out. Begin backfilling the hole with the amended soil mixture, carefully working it around the roots to eliminate air pockets that could dry out the plant. Firm the soil lightly with your hands, being careful not to compact it excessively, as this impedes drainage and root growth.
The goal is to cover the roots completely while leaving the top of the crown’s buds barely visible or buried under no more than one to two inches of soil. Immediately after planting, give the area a deep, thorough watering to settle the soil around the crown and initiate the hydration process. This initial soaking establishes good contact between the roots and the surrounding earth, which is necessary for nutrient and water uptake.
First Year Care and Harvesting Guidelines
Consistent moisture is necessary immediately following planting and throughout the first growing season to ensure the newly transplanted crown establishes a robust root system. Newly planted rhubarb should receive approximately one inch of water per week, either through rainfall or supplemental irrigation, especially during periods of drought or high temperatures. Allowing the soil to dry out excessively can significantly stress the young plant and impede its development.
Applying a three- to four-inch layer of organic mulch, such as straw or shredded leaves, around the plant helps regulate soil temperature and conserve moisture. The mulch also serves the function of suppressing weed growth, which is beneficial since the young rhubarb plants cannot tolerate competition. Remove any weeds by hand to avoid disturbing the shallow, developing root system.
If the rhubarb produces a flower stalk during the first year, it should be promptly cut off at the base to redirect the plant’s energy back into root and crown development. The most important rule for long-term patch health is strictly delaying the harvesting of any leaf stalks during the entire first growing season. This period of rest allows the plant to accumulate sufficient energy reserves in the crown, which is necessary to support years of future production. Harvesting should be delayed until the second or ideally the third year, ensuring a vigorous and long-lived patch.