Key Points:

· Timing of pruning can affect amount of bloom or fruit.

· Timing of pruning can affect growth habit and shape.

· Pruning to correct storm or other damage or remove disease or insect problems may be accomplished anytime.

Proper timing helps to ensure desired results from pruning. Some plants are susceptible to diseases if pruned at the wrong time of year. The quality of the bloom as well as size, shape and aesthetics of the plant can be ruined.

Late Summer and Fall

Some trees have free flowing sap and will 'bleed' excessively if pruned in early spring. While unsightly, the bleeding sap causes little harm to the plants. Such trees include: maples, honey locusts, butternuts, walnuts, birch, ironwood, beech and elm. Prune these trees in late summer or as leaves are falling. Prune only very lightly in early summer to minimize bleeding.

Early Spring – Prebloom

Flowering fruit trees or shrubs that bloom along the sides of branches or on spurs of last year's growth should be pruned in early spring before bloom or new growth occurs. Pruning consists of thinning out excessive branches and removing water sprouts, suckers and diseased or damaged wood. These species include:

Apple (Malus)

Pear (Pyrus spp.)

Cherry (fruiting varieties) (Prunus spp.)

Peach (fruiting varieties) (Prunus spp.)

Apricot (Prunus spp.)

Bush Cherries (such as P. tomentosa)

Cotoneaster spp.

Pyracantha spp.

Holly spp.

Flowering Quince (Chaenomeles spp.)

Chokeberry (Aronia spp.)

Crabapples (Malus spp.)

Hawthorne (Crataegus spp.)

Barberry (Berberis spp.)

Buckthorn (Rhamnus cathartica)

Buffaloberry (Shepherida argentea)

Peashrub (Caragana spp.)

Alpine Currant (Ribes alpinum)

Sumac (Rhus spp.)

Smoke Tree (Cotinus coggygria)

Euonymus spp.

Ninebark (Physocarpus spp.)

Bush dogwood (Comus stolonifera, C. sericea, C. sanguinea) that are grown for their brightly colored bark are pruned hard by thinning out part of the canes to the ground in the early spring to develop strong new shoots. The young bark is more brightly-colored than older bark.

Plants that bloom on current season's growth should be pruned in the spring before growth starts. The following plants are usually pruned to the first or second pair of buds above the ground at that time.

Clematis (most varieties)

Garden Roses

Hydrangea spp.

Rose of Sharon (Hibiscus syriacus)

Spirea (Summer flowering)

Umbrella Catalpa (Catalpa bignonioides) Beautyberry (Callicarpa giraldia)

Butterfly Bush (Buddleia spp.)

Early Spring – Postbloom

The following trees and shrubs bloom early in the growing season on two-year old or older wood. Prune them immediately after they finish blooming and before new growth starts. Pruning normally consists of cutting out older ,branched, or twiggy growth. Winter injured stems can be pruned any time they become noticeable.

Chokecherry (Prunes virginiana)
Deutzia spp.

Flowering Plum (Primus spp.)
Flowering Almond (Prunus triloba)
Flowering-Peach (Praaus-argentea)

Early to Mid Summer

Spruce firs, and pines put on a single main flush of growth each spring. New pine shoots or candles are pruned when the needles are about half grown. This stage can easily be determined by comparing the new needles with those formed the previous season. Spruce can be pruned from the early spring through late summer. Young, succulent growth is delicate and easily damaged during pruning. When pruning during the late season, use fork or thinning cuts, removing entire laterals at branching points. Don't cut into the previous year's growth. Fir can be pruned by pinching new shoots when they are about half grown, but this succulent growth is easily damaged. Firs are best pruned during July or early August. Cut laterals and leaders back to a strong bud. Other plants to prune at this time are:

Flowering Cherry (Prunus spp.)
Forsythia spp.

Honeysuckle (Lonicera spp.)
Japanese Kerria (Kerria japonica)
Lilac (Syringa spp.)

Magnolia (Magnolia spp.)

Mockorange (Philadelphus spp.)
Pussy Willow (Salix discolor)

Serviceberry (Amelanchiers spp.)
Spirea (spring flowering)

Viburnum spp.

The following shrubs bloom late in the spring on two-year old or older wood and should be pruned either early in the spring before growth starts or immediately after bloom:

Potentilla spp.
Shrub Roses (Rosa spp.)
Weigela spp.

Any Time

The following evergreens grow continuously through the growing season and can be pruned at any time, but early in the growing season is usually best:

Juniper

Hemlock (Tsuga spp.)

White Cedar or Arborvitae

Yew (Tanus spp