Pruning Hedges Or Screen Plants
To shape a hedge, begin pruning when plants are small and continue throughout the life of the plants. A hedge requires more pruning than other plants because a formal shape is desired. In general, a hedge should be pruned so that it is broader at the base than at the top.
Both deciduous and evergreen plants are used for hedges, and the methods of pruning vary somewhat.
Occasionally the lower part of a hedge consists of old, woody bare of leaves - all the leaves and flowers are produced at the tops of the plants. A spirea, privet or forsythia hedge can be cut back to the ground in late winter. The new growth that develops can then be shaped as recommended.
Some plants used for a hedge, such as burning bush and viburnum cannot be cut back this drastically but will tolerate a gradual cutback. Cut back one third of the oldest woody stems to the ground. This will allow young growth to develop. Cut back the other growth one-third to one-half or more to encourage branching. If this is done over a period of two or three years, it will be possible to get the hedge in shape.
Remember to prune to keep the base broader than the top. Pruning during the summer to remove feathery new growth is all that is usually required. Certain evergreens, such as yews, are more suited for growing as a hedge than others, so select plants carefully.
Deciduous plants used for screening should be pruned as if they were individual specimen plants. Evergreens used as screens are generally the larger types, such as spruce, pine, arborvitae, hemlock and upright junipers. Most of these plants should be allowed to grow naturally and be pruned as described in the Upright Narrowleaf Evergreen section. Hemlock can then be sheared much the same as any other evergreen used as a hedge.
This article was prepared by students and professors at Michigan State University Extension, Home Horticulture.