K-State Research and Extension

Q: Someone gave me a rhubarb plant, what do I need to know about transplanting, growing and eating this crop?
A: Rhubarb is a perennial vegetable that is grown for its large, thick petioles or leafstalks. It is known for its acid flavor and used in sauces, jellies and pies, either alone or in combination with other fruits.
Rhubarb grows well in many soil types, but it thrives in rich, well-drained loam soils. In most Kansas soils, generous applications of organic matter should be incorporated before rhubarb is planted. Using 50 to 100 pounds of barnyard manure or a similar organic material per 100 square feet of garden area is beneficial. Because rhubarb is a perennial, it should be located to the side of the garden or in an area not disturbed by yearly tilling. An established planting should be fertilized each year using 4 to 5 pounds of 1-10-5 (or the equivalent) per 1,000 square feet broadcast over the plot and worked into the soil early in the season before growth begins. Adding 2 to 3 pounds of ammonium nitrate per 1,000 square feet over the plot after the spring harvest season will provide nitrogen for good summer foliage growth.
Rhubarb should be planted in the early spring. In Kansas, the suggested planting time is mid March to early May, about the same time as Irish potatoes. Rhubarb is propagated by planting pieces of older crowns or roots. The pieces are taken from dormant three-year or older crowns. The crowns may be purchased from garden dealers or seed dealers, or dug from a healthy, established planting during the dormant season. If you dig your own crowns, split them into pieces with each containing one large “eye” or bud. Each crown should produce four to eight pieces suitable for planting. Crowns should be kept moist until planted and should be solid, not spongy. Plant rhubarb in a shallow trench so each bud is about one half to 1 inch below the soil surface. Plants should be 2 to 3 feet apart in the row, and if more than one row is planted, 4 to 5 feet between rows. Fill in the trench to cover the crowns and firm the soil around them. Make sure there is not a “depression” along the row so excess water drains away quickly. Compared with most other vegetable crops, relatively few varieties of rhubarb are available. The two varieties that have been used most widely in Kansas are Canada Red and McDonald.
Rhubarb will lose productivity after 5-10 years, with very productive plantings requiring more frequent rejuvenation. Dig and divide crowns in the early spring by cutting older crowns into sections with a sharp cleaver or axe, leaving at least one bud or eye on a root section. Probably no other single factor affects home gardeners’ success with rhubarb more than harvesting too much or too long. Rhubarb is a perennial crop, and its vigor and strength depend on stored food reserves that it accumulates during the previous season. For this reason, it is good to limit harvest the first several years. Rhubarb should not be harvested at all the first year, and only a few stalks should be taken the second year to insure a well-established planting that will last for many years.
Some years, it is common for rhubarb to produce a large, yellow seedstalks during the growing season. Seedstalks should be broken off and removed as soon as they form. Removing seedstalks will cause more food to be stored in the crowns and roots encouraging more leaf growth.
CAUTION: Rhubarb leaves contain oxalic acid that may cause lesions in the mouth if eaten, so only the stalks or petioles should be eaten. After harvest, rhubarb stalks should be stored in the vegetable storage area of the refrigerator and kept moist until used.