Nursery crops, like any other product, must be made ready for sale before the time they are sought by the customer. Since the greatest sale of nursery plants occurs in the spring, most plants are dug, bare-rooted or balled-and-burlapped, graded, and prepared for sale in the fall. In regions of the country where spring arrives late and the ground freezes deep, it is impossible to dig enough material in the spring. Fall digging also allows the nursery workers to grade, prune, bundle, and package the stock throughout the winter months.
If an entire row of shrubs is to be dug and bare-rooted, a forked, U-shaped blade pulled by a tractor may be used. As it lifts the plants from the ground, nursery workers shake off the soil and place the plants
on a truck. The plants are taken to shaded storage areas where the roots are covered with soil or other materials to prevent drying until they can be graded and bundled.
Plants that are to be balled-and-burlapped may be dug by rows or by a pattern that harvests some plants while leaving others for a later time. Mechanized tree and shrub spades are used by some nurseries to dig plants for burlapping, but the majority are dug by hand. Squares of burlap large enough to cover the ball are available precut or can be cut off a roll. Burlap is also available in a treated (rot-resistant) or untreated form. Treated burlap is more expensive but is needed if the plants are to be stored unplanted for a while. Untreated burlap can be used when the plants are going to be transplanted soon after harvest.
For best sales appeal, the soil ball should be nicely rounded, not flat or misshapen. It should contain enough roots to ensure survival of the plant, yet not be unnecessarily heavy (Figure 21-12). The burlap can be secured with twine or with pinning nails. Larger plant balls can be secured using the technique of drum-lacing, in which twine is wound around the ball and then laced in a zig-zag pattern (Figure 21-13). All balled-and-burlapped plants should be lifted and carried by the soil ball, not by the branches (Figure 21-14). Large plants can be moved with a forklift, tractor, crane, or ball cart. The ball should be handled carefully to prevent it from breaking apart.
figure 21-12. This conifer has been dug with a large soil ball and now must be burlapped and tied. (Delmar/ Cengage Learning. Photo by Jack Ingels.)
figure 21-13. An example of drum-lacing. The technique binds the burlap and soil ball tightly. It is helpful with large, heavy plants to prevent breakage of the soil ball. (Delmar/Cengage Learning. Photo by Jack Ingels.)
figure 21-14. A balled-and-burlapped plant should be lifted and supported from beneath. The soil ball should never be permitted to pull on the plant. (Delmar/Cengage Learning. Photo by Jack Ingels.)
After burlapping, the plants can be bedded (or heeled in) with sawdust, peat moss, or shavings to keep the roots and soil ball moist until grading and sale. In warm climates, some harvested plants may require special care. For example, cacti need a week for the roots to air-dry and heal. In the southeast, tropical plants grown for interior use require carefully controlled light reduction to prepare them for transplanting.
In recent years, nursery growers have introduced several variations on the traditional balled and burlapped plant. Wire baskets lined with nontreated burlap accept the harvested plants’ soil balls directly from the field. The baskets are then tightened around the balls, with soil added if necessary to create the roundness desired for marketing appeal (Figure 21-15). Containerized plants harvested from the field are also commonly available today. Immediately following digging, the plant balls are set into containers, then held for several weeks while the root system regenerates. This method of harvest can be done almost any time the weather permits digging.
Nursery stock is graded in accordance with the American Standards for Nursery Stock developed and published by the American Nursery and Landscape Association (ANLA) in Washington, D. C.
figure 21-15. This tree ball has been placed directly from the field into a burlap lined wire basket, then tied at the top with twine. (Delmar/Cengage Learning)
Containerized plants require little preparation for sale other than cleaning weeds from the containers, grading, and perhaps tagging them with names, plant patent numbers, or other information. If a fiber mulch ring has been used for moisture retention or weed control, it should be removed before sale.