Whitcomb, C.E. 1979. Research findings examined at Oklahoma field day. Am Nurseryman 150(11): 9, 54, 56, 58-59, 62-66.
Steve Shoup determined if the general recommendation of pruning 30 percent of the top of bare-root trees at planting time remains valid with current nursery practices. He also examined the widely promoted practice of withholding fertilizer from newly planted trees. Neither pruning nor fertilizer treatments at planting time had any effect on survival of any of the 10 species, a total of 480 trees. Pruning in excess of 15 percent reduced the visual quality of all species. Rick Reavis studied the effects of a root stimulator on root initiation and growth of newly planted pin oaks. No consistent benefit could be measured from either of the root stimulator treatments. Ken Preaus studied four ways of transplanting trees. For each species putting spade-dug trees into spade-dug holes brought the worst results. Dr. Whitcomb said studies have shown repeatedly that incorporating soil amendments in planting holes is harmful, not beneficial, to newly planted trees and shrubs.
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