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Asparagus and Rhubarb (H61)

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.

Todd Weinmann,Extension Agent, Cass CountyAgriculture and Natural Resources – Horticulture

Ron Smith, Extension Horticulturist, retired


Asparagus

Asparagus

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. Avoid any sites that may become waterlogged during spring rains.

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 and Canada thistle, before planting.

Barnyard manure, compost or peat incorporated into the soil the fall before planting will enhance growth and establishment of asparagus. 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.

If you select the planting site carefully, the asparagus bed could last 30 or more years.

Plants or Seeds

Asparagus may be started from seed. However, if you need only a few plants for the home garden, purchasing the crowns from a seed company or nursery usually is best.

Varieties

Martha Washington, Jersey Giant, Jersey Supreme, Purple Passion, Jersey Giant, Jersey Knight, Knight, Prince, Mary Washington, Viking and Viking KB3 are good options. Also consider trying several “super males” in North Dakota. They are 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 should be spaced 18 inches apart in the row. The plants need full sun to grow successfully.

 Asparagus trench

Culture

Because the harvest of shoots begins when frost is still possible, do not allow emerged shoots to become frosted. Frost damage to 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 1 bushel per 30 square feet in the fall.

One annual application of commercial fertilizer can be broadcast over the row by spreading 10-10-10 or an equivalent fertilizer at a rate of 1½ to 2 cups over 10 feet of row. It may be applied 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 because herbicide use may damage the plants. Herbicide use should be minimal, and use only those labeled for asparagus.

Harvesting

Harvest asparagus the third season of its growth, not earlier. Do not cut it in the last week of June or beyond this.

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 through the winter to catch and hold snow. This may help prevent deep freezing and sudden changes in soil temperature. The added moisture provided by melting snow also is important to the crop of shoots produced the following spring.

Remove the dead tops in the spring before growth starts.

Rhubarb

Rhubarb

Rhubarb is easy to grow and will stand considerable neglect and still be there the following spring. Two or three rhubarb plants usually are adequate for the average family.

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

Rhubarb sometimes will produce a flower stalk. Remove it immediately. It is not edible.

Soils

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

Divide Plants to Reset

Rhubarb usually is 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 and growing them from seeds is not recommended.

If you plant more than one row, 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 usually is planted at one side of the garden, where it will not be disturbed when the main garden is plowed or rototilled in the fall. The end of the asparagus row is a good location. Rhubarb needs full sun to grow successfully.

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 three to four 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.

March 2016

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