Q. How and when should I prune shrubs?

Answer

Here are a few rules for pruning shrubs:  

  • Remove dead, damaged or diseased branches at any time of the year.
  • If the shrub becomes too large or less attractive, or doesn’t flower well, it can sometimes be rejuvenated by more extensive pruning. This can be done by cutting back about a third of the stems almost to the ground each year for three years. Shrubs that can be pruned in this way include abelia, deutzia, lilac, mockorange, spirea and weigela.
  • Let the shrub grow into its natural shape (except hedges and topiary).
  • Some shrubs, e. g., repeat-flowering roses, butterfly bushes (Buddleja),  Japanese beautyberry (Callicarpa japonica) and some spireas, respond well and produce more flowers when pruned back hard every year in late winter or early spring.
  • Many shrubs rarely need pruning, e.g. barberry (Berberis spp.), flowering quince (Chaenomeles japonica), rose-of-Sharon (Hibiscus siriacus), and witch hazel (Hamamelis spp.).
  • In general, early-flowering shrubs such as forsythia and lilacs should be pruned after flowering, whereas summer-flowering shrubs, e.g.,summersweet (Clethra alnifolia), should be pruned in early spring. (Consult the references for a more detailed list).
  • Prune close to a bud or shoot with a diagonal cut.
  • Some shrubs are hard-pruned to showcase their colorful new shoots, e.g bloodtwig dogwood (Cornus sanguinea). This should be done in late winter or early spring.
  • Vines, e.g., clematis, may need special handling according to the species.
  •  Deciduous hedges should be pruned in late winter and may need to be pruned several times during summer, but they should not be pruned late in the growing season. Prune slow-growing evergreens, e.g  yews, in late spring or early summer when the new wood has started to harden. Hedges should be pruned so that the top is narrower than the bottom.
  • Evergreen shrubs should be pruned in late spring (early or mid-June) when new growth has slowed. They can be thinned by cutting back selected stems in March or April.
  • Take care not to cut back needled evergreens to old wood.

For more information, visit Pruning Shrubs and Pruning, Pared Way Down.

For tips on a variety of gardening topics, see our Plant Information Guides.
- Courtesy of NYBG Plant Information Service

 

  • Last Updated Apr 02, 2018
  • Views 99
  • Answered By Anita Finkle

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