Rhubarb is an over-looked vegetable that can be a good choice as a complementary spring vegetable, particularly for strawberry growers, and other early season roadside marketing situations. It is grown for its thick, edible petioles (leaf stalks), which have a strongly tart / sweet flavor, used most commonly in pies. It has particular potential if your market clientele includes retired folks more familiar with this vegetable (especially if they are from the Midwest and North-Central states). Younger people may need education on the use of this once very popular vegetable. Rhubarb takes minimum care, and a row or two planted near the market is an attractive harbinger of spring, and may be all you need to supply local needs. Like asparagus it is a perennial crop, and will remain productive for 5-8 years before it requires renovation. The broad leaves are inedible because of oxalic acid and oxalate content that can cause poisoning.
Rhubarb is grown commercially in the Northwest, California and Michigan. The potential for growing rhubarb successfully is good in most parts of Virginia. It is a cool season crop, and is extremely winter hardy. Depending on variety, it also requires at least 500 hours of winter temperatures between 28 and 49 degrees to form spring buds. Thus its culture may be somewhat limited in our warmer south-eastern coastal areas. In the hotter areas of the piedmont, Southside and SE, supplementary water and use of straw mulch will help plants withstand drought and the stress of summer heat.
Varieties: When choosing varieties consider (stalk) color, plant size, stalk thickness and length, flavor and tartness, yield, depth of dormancy and seedstalk forming tendency. A few examples:
- Tilden - good red color, spreading, thick stalks
- Victoria - good vigor, tart, long stalks, green w/pink speckling, many seedstalks.
- Valentine - medium vigor and good red petiole color, few seed stalks.
- MacDonald - fair pink-red color; very upright, produces many thinner, tender stalks, moderate seed stalks, some resistance to crown rot problems, so best for heavier soils.
- Crimson - red color throughout stalk, thick
- Canada Red - cherry red through stalk, higher sugars, for cooler regions
- Red Cherry - reported to be low in chilling, dominant California variety
Growing requirements: Rhubarb is adapted to cool regions, but can be grown in Virginia. Best soils are deep, well drained, fertile loam soils, supplied with ample organic matter and with a slightly acidic pH of 6.2-6.8. The phosphorus and potash levels should be adjusted to "high" soil test levels prior to planting. A pre-plant application of compost, old manure or organic matter is recommended.
Culture: Buy new plants (crowns) or divide the crowns from older plants. Crowns are divided by cutting into pieces with 2 to 3 buds. Plant as soon in the spring as the soil can be worked. In heavy soils make a raised planting area, 4-6" high for better drainage. Space plants 2-3 feet apart in the row, with rows 3 to 5 feet apart. Set roots in holes 6 inches deep, with the crown buds just below the soil surface. Firm soil and water plants in.
Control weeds by shallow cultivation or mulching; the large leaves will also shade the soil for weed control. Mulch with strawy manure each dormant season for best results, irrigate during dry summer periods.
Bolting or seed stalk formation is influenced by stress, age, and variety. The green stalked varieties are most susceptible, as are older plants. Infertile soil, heat, cold, daylength or drought may cause plants to bolt. The flower stalks should be cut out while they are still small.
The average planting should last 5 to 8 years or longer. After which division is needed to keep plants vigorous.
Fertility Tips: Moderate to high nutrient levels favor vigorous and heavy growth. At planting, incorporate 2 to 4 pounds of 12-12-12 per 100 feet of row. For established plants, make applications of 1-2 pounds of 12-12-12 per 100 foot of row prior to growth each spring, or an equivalent of nitrogen only fertilizer. Rhubarb also responds to manure applications, and fall applied "manure mulches" are beneficial to the crop.
Key Pests: Rhubarb curculio and crown rot can be problems, depending on the site. The rhubarb curculio can be managed by eliminating curly dock weeds in nearby areas, which are also a key host for the insect. Crown rot can be prevented by selection of a good, well-drained soil and/or planting in raised beds for good water drainage.
Harvesting and storing: No harvesting should be done the first year, only lightly in the second year, and in the third year 4-8 weeks. Established plantings can be harvested 8 to 10 weeks or longer if the plant is growing vigorously. Expect on average 2.0-3.0 lbs of stalks per mature plant / season.
Quality is highest and fiber lowest in the early spring, however, a well cared for planting can be utilized sporadically throughout the summer months. Select new, fully sized stalks and harvest by pulling the petiole or stalk from the base of the plant, then trim off leaf blades. Do not cut the stem. Never remove more than 2/3 of existing stalks at any given time and always leave at least 10-12 stalks. Avoid harvesting frost-damaged plants, as oxalate in leaves can migrate into the stalk under freezing stress. Harvested stalks may be stored for 2 to 4 weeks at 32° and 95% relative humidity. Quality for culinary use or freezing is best when stalks are first harvested versus storage.
Originally printed in Virginia Vegetable, Small Fruit and Specialty Crops – April 2002.
Virginia Cooperative Extension materials are available for public use, reprint, or citation without further permission, provided the use includes credit to the author and to Virginia Cooperative Extension, Virginia Tech, and Virginia State University.
Issued in furtherance of Cooperative Extension work, Virginia Polytechnic Institute and State University, Virginia State University, and the U.S. Department of Agriculture cooperating. Edwin J. Jones, Director, Virginia Cooperative Extension, Virginia Tech, Blacksburg; M. Ray McKinnie, Administrator, 1890 Extension Program, Virginia State University, Petersburg.
July 23, 2009