There are few similarities between landscape pruning (described in Chapters 11 and 12) and the pruning of nursery plants in production. The objectives of landscape pruning are to improve the health or appearance of the plant or to limit its growth; the objective of nursery field pruning is to promote and direct branching, and create a fuller plant as quickly as possible. Fullness adds measurably to the sales appeal of the plant. Shade and specimen trees, and certain specialized plants such as fruit trees, require individual attention and hand-pruning during production. Plants grown in mass quantities for the seasonal market cannot be given such time-consuming and costly attention.
Trees require more time to shape and develop than do shrubs. Trunk development and crown shaping are both of importance. To develop straight trunks with smooth bark and strong scaffold limbs with wide crotch junctions requires individual attention at least once during each year of field growth.
Evergreen trees must have their candles (the new growth) pinched in the spring before growth fully expands if the developing trees are to benefit by the pruning. If the trees are intended to be cut for Christmas
sales, the only objective is to add fullness. If the trees are intended for landscape use, the pruning can direct growth to fill in holes in the plant, remove conflicting branches, and add fullness.
Evergreen shrubs are sheared in the early spring before their annual flush of growth begins. The shearing promotes lateral branching of the shoots and creates a fuller plant. If the shrubs have a pyramid or columnar form, care must be taken to respect their natural shape and not cut off the lead shoot(s). If the shrubs are rounded or spreading forms, the shearing is directed to heading back the lateral branches.
Deciduous shrubs, particularly those that are to be bare-rooted at harvest, often get the least individual attention because they bring the least return at the market. They are commonly pruned with a sharp cutting bar driven down the nursery row, removing about a third of the previous season’s growth in the process.