Rhubarb is a classic garden vegetable that reliably returns each season, making it a favorite for long-term planting. It is classified as a hardy perennial plant, meaning it lives for more than two years, unlike annuals that complete their life cycle in a single season. Once established, a rhubarb crown will continue to produce its tart, edible stalks for many years, provided it receives appropriate care.
The Perennial Nature and Lifespan
Rhubarb survives the winter and regrows annually due to a specialized underground structure called the crown, which is a type of rhizome. The crown acts as the plant’s primary storage unit, accumulating energy reserves during the active growing season. While the large, leafy foliage dies back to the ground with the first hard frost, the crown remains alive and dormant beneath the soil surface.
The stored energy fuels the initial burst of growth in early spring, producing the first harvestable stalks. With proper maintenance, a single rhubarb patch can remain productive for 10 to 15 years. This long lifespan makes rhubarb an excellent, low-maintenance feature for a permanent garden space.
Essential Requirements for Successful Regrowth
For a rhubarb plant to successfully return year after year, it must build up sufficient energy in its crown during the summer months. Rhubarb thrives in rich, well-draining soil that has been heavily amended with organic matter, such as compost or well-rotted manure. The soil pH should be slightly acidic, ranging between 6.0 and 6.8, to support robust growth.
The plant performs best in full sun, though it can tolerate partial shade, especially in warmer climates where it benefits from afternoon relief. Rhubarb is considered a heavy feeder, particularly requiring nitrogen to support the growth of its large stalks and leaves. Applying a balanced fertilizer or a nitrogen-rich dressing like aged manure in the early spring helps maximize yields, but avoid covering the crown itself. Consistent moisture is necessary, requiring supplemental watering during dry periods.
The Winter Cycle: Preparing for Dormancy
Rhubarb is a cool-season vegetable that requires a specific cold period, known as vernalization, to stimulate new growth. The plant needs winter temperatures below 40 degrees Fahrenheit for six to eight weeks to successfully break dormancy and trigger new spring buds. This chilling requirement makes rhubarb well-suited to cold northern climates.
Once foliage is killed by a hard frost in late fall, the dead leaves should be cut back to the ground. This step reduces the chance of fungal diseases overwintering and directs remaining energy into the crown. In regions with extremely cold winters and little snow cover, a layer of straw or mulch can be applied over the frozen ground for insulation. However, pull this mulch away from the immediate crown area in early spring to prevent rot.
Maintaining Vigor Through Crown Division
While rhubarb is long-lived, its productivity naturally declines over time as the crown becomes overcrowded and congested. After about five to ten years, the stalks will typically become smaller and thinner, signaling that the plant needs rejuvenation through division. Dividing the crown is a maintenance practice that ensures the plant continues to return with the same vigor it had when it was younger.
The best time to divide a rhubarb crown is when the plant is dormant, either in the late fall after the foliage has died back or in early spring just as new growth begins. To divide the plant, the entire crown must be carefully dug up, using a spade or fork to loosen the surrounding soil.
The dense, woody root mass is then cut into sections. Ensure that each new piece has at least one prominent bud, often called an “eye,” and a healthy portion of roots attached. These smaller divisions are then replanted immediately in prepared soil, spaced at least three feet apart, to establish a renewed, productive patch.