Pruning young trees helps them develop a desirable shape and branch structure. As nut trees become larger, pruning is usually limited to removing dead or damaged branches. With a minimal amount of pruning, nut trees usually develop a strong and attractive structure if they have adequate space.
Following heavy cutting-back at planting, several shoots may compete for the position of the new leader or main trunk. When the new shoots are 8 to 12 inches long, select the strongest and straightest 1 for the leader and pinch out the growing tips of the competing ones. In late winter or early spring each year, shorten the lower branches. If any of the lower branches grow vigorously during the growing season, pinch out the growing point. As the tree grows taller, the lower branches can be cut off flush with the trunk; remove a few of these lower branches each year.
Leaving the lower branches on the young tree aids its overall growth by increasing its food-manufacturing ability and providing shade for the trunk during the growing season. Limiting the growth of the lower branches by cutting back and pinching out the tips of vigorous shoots keeps them small and reduces the size of the pruning wound when they are removed later.
Eventually all branches arising from the trunk within 6 to 8 feet of the ground should be removed. This facilitates mowing and other cultural practices.
The pruning practices described here for transplanted trees are also suggested for trees started from seed and for varieties grafted onto seedling trees.
Filberts, which are large multistemmed shrubs, should be pruned like lilacs, mockorange, and other large shrubs. Thin out the smaller and weaker shoots each spring, cutting them off at ground level. Remove any damaged, diseased, or weak older stems, cutting them off near the ground level. A shrub with 5 to 7 main stems is suggested. Winkler is usually more bushlike than the hybrid filberts.