Rhubarb ( Rheum x hybridum) is a robust herbaceous perennial known for its long life, returning each year from the same root structure. A well-maintained plant remains productive for 10 to 15 years, often extending its lifespan to 20 years or more under exceptional growing conditions. This longevity is linked to a specialized underground structure that allows the plant to persist for decades by surviving harsh winters and regenerating new growth season after season.
The Biological Structure Enabling Long Life
The remarkable endurance of the rhubarb plant is centered on its crown, a thick, fleshy rootstock situated just below the soil surface. This crown is a modified stem and root mass, functioning as the plant’s primary energy storage organ. Throughout the spring and summer, the large leaves photosynthesize and direct sugars down into this crown, building up reserves.
The crown is lined with numerous buds, or “eyes,” which are the dormant growth points for the following season’s stalks and leaves. When temperatures drop, the above-ground foliage dies back, and the plant enters dormancy. The stored energy within the crown protects the plant from freezing and fuels the vigorous burst of new shoots that emerge in the spring. This cycle of dormancy and regrowth, facilitated by the energy-rich crown, allows the plant to function as a long-lived perennial.
Environmental and Disease Factors That Shorten Lifespan
While rhubarb is naturally long-lived, its lifespan is often cut short by unfavorable environmental conditions and specific diseases. The most common factor leading to plant failure is poor soil drainage, which causes the roots and crown to sit in water. This condition, often termed “wet feet,” quickly leads to root rot and crown rot, which is a fungal disease that rapidly destroys the plant’s regenerative center.
Rhubarb requires a period of cold temperatures, known as a chilling requirement, to properly break dormancy and encourage robust growth. Without this necessary winter chill, the plant becomes stressed, resulting in weak, spindly stalks and a reduced lifespan. Excessive summer heat, especially when coupled with insufficient watering, significantly stresses the plant and drains its energy reserves.
Improper harvesting techniques can create entry points for pathogens that shorten life. Cutting the stalks with a knife instead of gently pulling and twisting them away from the crown leaves a vulnerable stub susceptible to fungal infections. Excessive harvesting, particularly in the first two years of growth, prevents the plant from storing adequate energy in the crown, which compromises its ability to thrive.
Rejuvenation Through Dividing the Crown
Even healthy rhubarb plants eventually experience a decline in productivity, after five to eight years, as the crown becomes large and overcrowded. This overcrowding leads to competition for nutrients and causes the stalks to become thinner and less vigorous. Division is a necessary maintenance practice that rejuvenates the plant, restarting its productive lifespan.
The process involves carefully digging up the entire crown during the plant’s dormant period, either in late fall after the foliage has died back or in very early spring before new growth begins. The massive rootstock is then physically split into smaller pieces using a sharp spade or knife. Each new division must contain at least one healthy, visible bud, or “eye,” and a generous portion of the root system.
These smaller divisions are replanted immediately in fresh soil, spaced appropriately to prevent overcrowding. Division prevents the central, older part of the crown from becoming unproductive and stimulates vigorous new growth from the younger buds on the periphery. This process allows a single rhubarb plant to be propagated and maintained almost indefinitely, ensuring continuous, high-quality harvests for decades.