Pruning Guide For Trees and Shrubs

Pruning Trees and Shrubs

A very common question our nursery professionals are asked is when do I prune my tree or shrub. The answers depend upon multiple factors such as purpose of pruning or when flower buds are produced. Here is a guide to help you determine if and when to prune in your landscape. If you would like a copy to download and keep please click here.

Why Prune?

➢ These are some common goals for pruning

  • Maintain the shape and size of a plant
  • Remove damaged, dead, or diseased wood
  • Correct poor branching to avoid future problems such as splitting branches from snow load, branches growing into buildings, or poor form.
  • Rejuvenate and older plant that hasn’t been consistently maintained
  • Increase new growth for color, flowering, and fruiting
  • Shape plants into specific forms such as for hedges or topiaries

➢ Tips

  • Know the goal of pruning a certain plant before starting. This will help guide you on what cuts to make and when to make them.
  • It’s not mandatory to prune all plants. Some plants grow a very uniform shape and are smaller in size so require no pruning to maintain. In other cases, a natural form or larger size may be more desirable.
  • Start pruning plants on a routine schedule when young if pruning will be necessary. It’s easier to make changes early and the plant will look better if pruning is done consistently rather than making large corrective changes on more mature plants.
  • Check the timing of your pruning for specific plants so that health and performance are helped rather than hindered.
  • Follow a branch to see how much is attached to it before you cut. It may be that there are more branches connected to what you’re pruning than you realize. Once you’ve cut it, you can’t put it back
  • Use and maintain the proper tools for pruning. A dull set of pruners can leave a plant looking terrible and can create more opportunities for disease and insect problems.
  • Don’t be afraid to ask for help. Call the professionals if you don’t have the proper experience or equipment, especially with large trees and shrubs.

When do I prune?

➢ Different plants may need to be pruned at different times of the year. Here are some general rules for the timing of pruning your landscape plants.

  • Spring flowering trees and shrubs that bloom before June, such as Forsythia and Lilacs, overwinter flower buds on the previous year’s growth, “old wood”. They should be pruned immediately after flowering. If pruned later in the season, you risk pruning off the flower buds for the next year.
  • Summer flowering trees and shrubs that bloom after June, such as Rose of Sharon and Panicle Hydrangea, should be pruned in late winter to early spring before new growth starts. Flower buds are formed on “new wood” in the current growing season.
  • Reblooming flowering shrubs, such as Bloomerang Lilacs and Sonic Bloom Weigelas, bloom on both old and new wood. Lightly prune immediately after spring flowers are finished. This will increase flower production for more blooms later in the season and the next year.
  • Deciduous trees and shrubs where flowering is not important, such as Burning Bush and Privet, should be pruned in late winter to early spring. If using these plants as hedges, you can re-shape in early summer after the spring flush of new growth.
  • Coniferous evergreens, such as Arborvitae, Yew, Juniper, Fir, and Spruce can be pruned in late fall to early spring before new growth starts or late spring after the new growth has hardened. New shoots don’t usually develop on old wood so don’t cut back past the evergreen foliage to the inner wood.
  • Pines should be pruned when the new growth is at the candle stage. This is when the terminal buds on the branches elongate. Once the bud has finished elongating and the needles have expanded to 1⁄2 the length of the previous year’s needles, prune the candle back by half. This will maintain a denser form.
  • Maple, birch, dogwood, elm, and walnut have excessive sap flow in early spring. If pruned at that time, these trees “bleed” which isn’t harmful to the plant (i.e. maple syrup production) but it can be messy beneath the pruned trees. Prune when dormant from late winter to early spring. Once new growth has hardened off, these trees can be pruned up to late summer.
  • Oaks should be pruned in late winter to early spring, before 1 April or after July 1st when the new growth has hardened off. It’s very important to avoid pruning between April and July to help prevent a serious disease called Sudden Oak Death. Beetles that carry the disease are attracted to the new pruning cuts.
  • Fruit trees and Grapes should be pruned in late winter to early spring before they break dormancy. Flower buds are set on old wood so pruning will remove some potential fruit but will promote optimal growth and fruiting for the following season.
  • Perennials should be cut back after several hard frosts have shut down growth for the season. Most perennials can be cut back to the base. Do not cut Lavender or Russian Sage back to the base. These are exceptions.
  • Ornamental Grasses can be cut back to 4-6” either in the fall or in early spring before new blades emerge. Leaving the grass uncut in the fall provides a nice winter accent.

Roses 

  • Roses have multiple methods of pruning depending upon the type of rose.
  • Shrub roses that bloom on current year’s growth can be lightly pruned after they have gone dormant to clean off old flowers. In early spring, you can prune them harder to clean off any winter damage, increase density, and control size. Some older varieties, such as some Rugosa, bloom on old wood only. Prune them immediately after flowering.
  • Hybrid Tea, Grandiflora, Floribunda roses should be pruned to 24-30” once they have gone dormant for the season. Prune so that the rose will fit in whatever winter protection is being used. Avoid pruning back to the graft.
  • Climbing roses should be lightly pruned leaving the main canes. This is to clean up old flowers and to make winter protection easier to apply if necessary. Best flowering occurs on old growth so avoid pruning too much.

➢ Additional pruning tips

  • Remove dead or damaged wood as well as branches that rub together as soon as possible regardless of the time of year.
  • Avoid pruning in late summer to early fall to avoid stimulating new growth which may not harden before cold temperatures occur causing winter damage.
  • Rejuvenation pruning overgrown shrubs generally require extensive removal of overgrowth. The best time to do that is late winter to early spring.
  • Deciduous, multistemmed shrubs may require several years of pruning and several years to recover. Flowering may be impacted for years.
  • Evergreen shrubs generally, cannot be rejuvenated once they have been allowed to grow too large. Most evergreens do not have lateral buds on the woody inner stems so if they are cut back too far, they will not regrow new foliage.