Mel Garber, Extension Horticulturist; John Ruter, Nursery Crops Research
The production of in-ground ornamental trees should occur in four discrete stages: 1) starter material selection, 2) liner, 3) whip and 4) finished tree. Most of the ornamental trees produced in Georgia are grown in-ground (as compared to containers or grow-bags), and the industry has focused on finished trees (>2" caliper). The whips that serve as starting material for the finisher are purchased primarily from Oregon and Tennessee. Whip production is not currently practiced in Georgia. Development of the shade tree industry in Georgia would benefit from local production of high quality whips.
There are no inherent factors to prevent Georgia growers from producing high quality liners and whips. The other important consideration is that the tree industry in Georgia can increase significantly without any increased demand for trees. That is, as an industry, we can integrate vertically and reduce imports, resulting in a more complete industry.
The starter material refers to the initial material used to generate the new tree. Options include vegetatively or sexually propagated trees. Vegetative propagation includes cuttings, tissue culture and grafted material. Sexually propagated material is synonymous with seed. Whether a grower or customer of liners, it is important to know the origin of the starter material. This will have an impact on subsequent growth and the information should be passed on to the customer; i.e., was the seed from a northern or southern source?
The term liner refers to the first stage of plant growth. If it is a seed propagated plant, liner refers to the first year of growth in the seed bed. In forestry, this is referred to as a 1-0 seedling; i.e., one year in a seed bed without transplanting. Most liners of shade and ornamental trees are sold as 1-0 bareroot trees. Liners produced in the United States are generally grown in-ground, lifted during the winter, and transplanted/sold the next spring. The term liner also refers to container seedlings started either from seed, cuttings or tissue culture plantlets and grown for one growing season. The 1-0 and container liners are used as starter material for whip production.
Many catalogues refer to the liner stage as seedlings and, in some cases, will then have the notation of 1-0, 2-0 or 1-1. The 2-0 and 1-1 seedlings are more common for slower growing conifer species.
The next stage of production is referred to as whip production. The starter material for whips is the 1-0 or container liners. The liner is placed in the ground in the spring of the year and is allowed to grow for one growing season. If the plant is produced as a seedling, it is cut back to the ground at the beginning of the second year. Of the subsequent shoots that emerge, a superior shoot is selected for growth. The shoot is allowed to grow for one year; i.e., the second growing season of whip production. This plant is referred to as a one-year whip, indicating one year of growth after cut-back but two years of growth after transplant. If the whip is a budded plant variety, budding occurs in the fall of the first year. The plant is cut just above the bud the following spring. The shoot that emerges from the grafted bud is grown for one year. The term whip is derived from the fact that, after the second year, you have a tall, straight stem with minimal branching.
The third stage of production is the finished tree production. The starter material typically is a 1"-1.5" caliper whip. The bareroot whip is transplanted in the spring and grown for three to five years. The actual residency time will depend primarily on the variety and caliper of tree demanded by the market place. The material is typically handled or dug as a ball and burlap plant.
If trees are produced in three distinct stages, the chances of a quality finished product is greatly enhanced. When purchasing a liner or whip, be sure that the primary goal of each stage has been satisfied, since it is very difficult to improve upon the quality of the material purchased.
The primary goal for each stage of production is:
The purchase of starter material, whether liner or whip, is one of the best opportunities to exercise quality control in a production operation.
The University of Georgia and Ft. Valley State College, the U.S. Department of Agriculture and counties of the state cooperating. The Cooperative Extension Service offers educational programs, assistance and materials to all people without regard to race, color, national origin, age, sex or disability.
An Equal Opportunity Employer/Affirmative Action Organization Committed to a Diverse Work Force
Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, The University of Georgia College of Agricultural and Environmental Sciences and the U.S. Department of Agriculture cooperating.
Gale A. Buchanan, Dean and Director