Rhubarb (Rheum rhabarbarum) is a hardy perennial vegetable prized for its tart, edible leaf stalks. As a long-lived plant, it requires relocation or division every several years to maintain vigor and robust production, typically every five to ten years when stalks begin to thin due to overcrowding. The process of transplanting, which often involves dividing the root system known as the crown, rejuvenates the plant and expands your patch. Successful establishment in a new site depends heavily on executing the move at a precise point in the plant’s annual life cycle to minimize stress and maximize recovery.
Optimal Timing for Rhubarb Relocation
The best time to transplant rhubarb is during its dormancy period, when the plant is least active and most resilient to root disturbance. This period offers two distinct windows for gardeners: late fall or very early spring. Transplanting in late fall, after the foliage has naturally died back from the first hard frost, is often preferred because the plant’s energy has been fully withdrawn into the root crown for winter storage.
A fall move allows the roots to begin establishing themselves in the new site during the cool, moist soil conditions of late autumn and early winter. The ideal window is typically October through November in temperate regions, while the soil is still workable but before it freezes solid. When moving in the fall, the plant is not expending any energy on growing new stalks or leaves, meaning all resources are focused on root repair and anchoring.
The second suitable time is in the very early spring, just as the ground becomes workable but before new growth begins to emerge. This timing is still within the dormancy period, ensuring the plant has not yet committed significant energy to the season’s first shoots. If new growth has already started, it is still possible to transplant, but it increases the risk of transplant shock, making the dormant season the most reliable choice for a successful move.
Preparing and Dividing the Rhubarb Crown
Before excavating the existing plant, the new location should be prepared by ensuring the soil is well-drained and enriched with organic matter, like well-rotted compost or manure. The planting hole should be generous, dug two to three times wider than the crown you plan to move. Rhubarb crowns are highly susceptible to rot if they sit in wet soil.
To remove the old crown, use a sharp spade to dig deeply around the plant, approximately six inches from the central crown, to lift the entire root mass. Once lifted, the crown must be divided to create new, healthy plants. Use a sharp tool, such as a large knife or a spade, to cut the crown into pieces.
Each new division, or ‘set,’ must contain at least one healthy, visible bud, often called an ‘eye,’ along with a substantial section of the root material. Pieces should be roughly fist-sized, ensuring adequate root mass to support new growth. Replant these divisions so the buds are just below the soil surface, about one to two inches deep, and firm the soil gently around the roots to eliminate air pockets. New plants should be spaced approximately three feet apart to allow for mature growth and prevent future overcrowding.
Post-Transplant Establishment and Care
Consistent moisture management is necessary for the transplanted crown to establish itself successfully. Following planting, the area must be deeply watered to settle the soil around the roots and initiate the re-establishment process. Throughout the first few weeks, and especially during any dry spells, the soil must be kept consistently moist to support root development.
Applying a layer of organic mulch, such as straw or shredded leaves, around the new plant helps retain soil moisture and regulate temperature fluctuations. It is important to keep the mulch away from the crown itself to prevent moisture buildup that could lead to rot. Mulch also suppresses competing weeds, allowing the young plant to focus its energy on subterranean growth.
The most important rule for post-transplant care is to resist the temptation to harvest any stalks during the entire first full growing season. The plant must dedicate all available energy to developing a strong, expansive root system, which is severely compromised if stalks are removed. Allowing the leaves to grow and photosynthesize ensures maximum energy is directed below ground, guaranteeing a vigorous and productive plant for many years to come.