Asparagus and Rhubarb

H-61 (Revised), December 1987
Reviewed and reprinted February 2008

Ronald C. Smith, Extension Horticulturist and Turfgrass Specialist

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Asparagus is the earliest vegetable you can harvest from your garden in the spring. The young, tender shoots of asparagus usually reach cutting size about mid-May in North Dakota. New shoots may be cut as often as every other day if temperatures and moisture conditions are favorable.

Soil and Site

Asparagus can be grown on most any type of soil that is well drained. For large market garden plantings, site preparation should be started a year or more in advance of planting crowns. This aids in complete control of hard-to-kill perennial weeds, such as quackgrass, Canada thistle, etc., before planting. If barnyard manure is not available, a heavy green manure crop (soybeans or sweet clover) should be plowed down the preceding year to add as much organic matter as possible. Small home garden plots may be prepared a year ahead or planted directly if the area is free of noxious weeds. Barnyard manure, compost or peat incorporated into the soil the fall before planting will enhance growth and establishment of asparagus.

Plants or Seeds

Asparagus may be started from seed. However, if only a few plants are needed for the home garden, it is usually best to purchase the crowns from a seed company or nursery. Varieties Jersey Giant, Mary Washington, Viking and Viking KB3. Several "super males" should be given trial consideration in North Dakota: Greenwich, Jersey Centennial and UC 157.

Planting

Plant year-old plants in holes or a trench 5 to 6 inches deep in sandy soils and 3 to 4 inches deep in heavy clay soils. Rows should be spaced 4 to 5 feet apart while crowns are spaced 18 inches apart within the row.

Culture

Since harvest of shoot begins when frost is still possible, do not allow emerged shoots to become frosted. Frost damaged shoots will keep the crowns from yielding at the optimum level.

Asparagus responds to liberal annual applications of fertilizer. Well rotted manure or compost should be applied at a rate of one bushel per 30 square feet. One annual application of commercial fertilizer can be broadcast over the row by spreading 10-10-10 or equivalent fertilizer at a rate of 1� to 2 cups over 10 feet of row. It may be applied either in late fall, very early in the spring or after the harvesting season has ended in late June.

Recommendations to fit all conditions are difficult to make. The appearance of the plants has to be a guide. Keep in mind the vigorous top growth in one season is the best assurance for a good yield the following season.

Hand weeding the first year is a necessity, as herbicide use may damage plants. In subsequent years, the use of herbicides such as Simazine and Treflan will control most weeds.

Harvesting

Depending on the vigor of the plants, some harvesting can take place the first year. The cutting season should be short the first and second season, but the following year's cutting may begin when the first shoots appear and continue for about six weeks. Do not cut in the last week of June.

The shoots are best cut when 6 to 10 inches high. Push a knife into the soil close to the shoot, cutting it slightly below the soil surface, or simply snap the shoot off with your fingers.

Allow the Tops to Stand

Allow the tops to stand over winter to catch and hold snow. This may help prevent deep freezing and sudden changes in soil temperature. The added moisture provided by this melting snow is also important to the crop of shoots produced the following spring. Remove the dead tops in the spring, before growth starts.

Rhubarb

Fresh rhubarb sauce or pie is a delightful substitute for fresh fruit in late spring or early summer when other fruits are not yet in season. Rhubarb is easy to grow and will stand considerable neglect and still be there the following spring. Two or three rhubarb plants are usually adequate for the average family.

Rhubarb stalks (the leaf petiole) can be washed, diced and frozen for winter use. Pack raw or blanch for one minute in boiling water; cool in ice water, drain and pack unsweetened or use a syrup or sugar pack.

The leaves are not edible, either raw or cooked. Poisoning has been reported from eating the leaf blades of this plant.

Soils

Deep, fertile loams, well-supplied with organic matter, are best suited for rhubarb growing. Well-rotted manure benefits most rhubarb beds. Yields will be increased with clean cultivation and added fertility.

Divide Plants to Reset

Rhubarb is usually propagated by divisions of crowns formed during previous seasons. Crowns are divided in late fall or early spring. Take care to leave as much root as possible with each eye or bud. Plants from such crown divisions are preferred to plants raised from seed. Plants grown from seed seldom equal the production or quality of the named rhubarb varieties.

If more than one row is planted, rows should be 5 feet apart with plants 3 to 4 feet apart in the row. Set crowns about 4 inches deep. In the average garden, rhubarb is usually planted at one side of the garden where it will not be disturbed when the main garden is plowed or roto-tilled in the fall. At the end of the asparagus row is a good location.

Reset Every Fourth Year

Divide and reset plants about every fourth year to keep the bed in vigorous condition. Use a sharp spade or shovel to divide the crown, leaving 3 to 4 buds undisturbed in the old location. Portions removed may be used to enlarge the bed.

Do this renewal work in the fall or early spring. Plants not divided in this manner become large and the stalks become more numerous than is desirable. Remove seed stalks as they appear. They reduce the yield and vitality of the plant.

Use Recommended Varieties

Recommended rhubarb varieties for North Dakota are: Valentine, Ruby, McDonald, Canadian Red and Sunrise, varieties from Canada, are preferred.

H61(Revised), December 1987
Reviewed and reprinted February 2008