Asparagus Starts Up Slow But Goes On and On; Rhubarb Also Takes Its Own Sweet Time

by Stephen A. Garrison and J. Howard Ellison.

Stephen A. Garrison and J. Howard Ellison are Associate Professor and Professor respectively in Vegetable Crops, Rutgers University, New Brunswick, N.J.

The cultivated asparagus plant, Asparagus officinalis, is a perennial vegetable that can thrive in the home garden for 25 years or more when well cared for. However, plants may have to grow 3 years before they can be harvested.

The underground root system consists of an extensive network of fleshy storage roots with small feeder roots that absorb water and nutrients. The storage roots are about the diameter of a pencil and may be 5 to 10 feet long in mature plants, depending on the soil type in which the plants are growing These storage roots are attached to an underground stem called a rhizome. The storage roots and the rhizome are commonly referred to as an asparagus crown. When the soil is warm and the soil moisture favorable, buds arise from the rhizome and develop into edible spears, utilizing the carbohydrate and other nutrient reserves present in the storage roots.

The spears which are not harvested develop into attractive, green, fern-like stalks (brush). Through photosynthesis, the mature plant produces carbohydrates and synthesizes other essential nutrients that are translocated to the storage roots. The stored reserves supply the energy required to produce spears during the following growing season.

For this reason it is important to protect the fern-like foliage from insects, diseases, and other injury before natural senescence and cold weather terminate the functioning of the green foliage in the fall.

Spears should not be removed from the plants during the first two growing seasons in the permanent location. (See harvesting details later in chapter).

Unlike most plants that have both male and female parts on the same plant, the asparagus plant is dioecious. The male flowers that produce pollen are present on one plant and the female flowers that produce the berries and the seeds are on a separate plant. Bees transfer the pollen from the male to the female flowers.

Research has shown that female plants, which expend much energy in producing fruits and seeds, do not yield as well and are not as long-lived as male plants.

The genus Asparagus, a member of the Lily family, originated along the shores of the Mediterranean Sea and on its many islands. Asparagus (Asparagus officinalis) was considered a delicacy by the ancient Greeks. The elder Cato discussed its cultivation in 200 B.C., and 200 years later Pliny described the spear size of asparagus. A. W. Kidney, writing in England in 1959, said the spear size described by Pliny was very similar to that in England more than 19 centuries later. It is remarkable how little the cultivated asparagus has changed since the time of Christ.

Most asparagus strains grown in the United States today are seedling populations selected from the Martha and Mary Washington strains developed in the early 1900's by J. B. Norton of the U.S. Department of Agriculture.

All presently available asparagus strains produce plants with variable vigor, size and disease resistance.

Emerging asparagus spear.

Plant breeders are developing more uniform plants by reproducing selected parent clones through test-tube tissue culture. In the near future, gardeners will be able to purchase these high-yielding uniform seeds or even highly selected, extremely productive clones propagated by tissue culture.

The Viking strain is suggested for gardeners in the northern United States. For the West Coast, California U.C. 157 is recommended. In the East and Midwest, Rutgers Beacon, Waltham Washington, and local selections of the "Washington" type are recommended to home gardeners and are available through the major seed distributors.

Asparagus is low in calories, but high in flavor. A serving of 4 spears Of asparagus (60 grams) contains just 10 calories, 1 gram of protein, 2 grams of carbohydrates, and only traces of fat. When the nutrient content of vegetables is compared, asparagus is a good source of vitamin A and riboflavin, and a very good source of thiamin.

Environment Needs

Able to tolerate great variations in temperature, asparagus grows in places such as the Imperial Valley of southern California, where the temperature soars to 115 to 120 F in the summer, or Minnesota, where winter minimums of 40 below zero occur.

However, asparagus grows best where the growing season is long and the days are sunny for maximum photosynthesis. Ideal day temperatures during the growing season are 75 to 85 F, and nighttime readings in the 60 s to minimize respiration. These conditions favor maximum storage of carbohydrates in the root system for high yield and quality of spears the following season.

Asparagus can be a home garden vegetable in most parts of the country except the Deep South. Asparagus does not grow well in the Gulf Coast States, due to the moist, warm winters which may stimulate sporadic growth during winter.

Asparagus can be grown on a wide range of soil textures from loamy sands to clay loamy as long as water drainage and aeration are good. In the more and regions the heavy soils are satisfactorily aerated and produce excellent asparagus. However, in regions of moderate to high rainfall, asparagus grows best on deep, well-drained sandy loam soils. Asparagus plants lose vigor, become more susceptible to root rot, and die in poorly drained areas or following prolonged high rainfall.

The soil reaction (pH) should be maintained between 6.5 and 6.8. Medium fertility is best, to provide a balance between top growth and root Growth, but the plant has a relatively high potassium requirement for maximum production.