Pruning Deciduous Shrubs
Tagged as: Deciduous Shrubs, Pruning
The objectives of pruning shrubs are to maintain vigor, remove damaged or diseased branches, help maintain the natural size and shape of a plant, and improve flowering and fruiting. There are four basic pruning techniques used for maintaining shrubs: heading back, renewal, rejuvenation, and shearing.
TIME TO PRUNE
A general rule-of-thumb is that shrubs that bear flower buds on the previous year’s growth should be pruned after spring flowering. Some examples are forsythia, mockorange, and lilac. Shrubs that bloom on the current year’s wood should be pruned in early spring before bud break. Among these are St. John’s wort, cinquefoil, and snowberry. This rule does not apply when doing rejuvenation pruning.
HEADING BACK
Heading back is used to control the size of the shrub or to remove a branch that is out of balance with the rest of the plant. It requires that a branch be removed to a good bud or lateral branch instead of being cut to the ground. Heading back is best done when new growth is complete.
REJUVENATION
Some old, neglected shrubs can be restored to vigor by pruning all stems or canes to ground level. Among those that respond well to this treatment are: forsythia, weigela, privet, honeysuckle, spirea, and hydrangea. Rejuvenation pruning is best done in late winter or early spring.
RENEWAL Renewal is the removal of old, overgrown stems or canes. This is usually done over a period of three to four years, and 1/3 of the stems are removed each time. It is best done during the dormant season. This results in a more vigorous shrub and, in the case of flowering ornamentals, better flowering. 
SHEARING
Shearing is done only when a formal hedge is desired. When shearing, it is important to keep the top of the hedge narrower than the base to allow sunlight to reach the lower branches. The best time to shear is when new growth is complete.
| Common Name | Scientific Name | Method & When To Prune |
| Almond, flowering | Prunus glandulosa | renewal prune after flowering to encourage new growth |
| Barberry, Japanese | Berberis thunbergii | shear, thin, or rejuvenate in early spring |
| Bayberry | Myrica pensylvanica | renewal, heading-back, or rejuvenate in early spring |
| Beautybush | Kolkwitzia amabilis | renewal, heading-back, or rejuvenate after flowering |
| Bluebeard, Blue spiraea | Caryopteris x clandonensis | top dies back to ground in harsh winters; flowers on new wood; rejuvenate in early spring |
| Buckthorn, tallhedge | Rhamnus frangula | selective pruning to control shape using heading-back method; does not do well when sheared |
| Butterfly bush | Buddleia species | flowers on new wood, rejuvenate in early spring |
| Cherry, purple sand | Prunus x cistena | renewal prune after flowering |
| Chokeberry | Aronia species | occasional renewal pruning in late winter or early spring |
| Cinquefoil | Potentilla species | thin out oldest stems, clip to keep in shape |
| Cotoneaster | Cotoneaster species | shape plant when needed by heading-back; renewal prune in spring |
| Currant, alpine | Ribes alpinum | shear as hedge; prune in late spring after new growth matures rejuvenate in early spring |
| Deutzia | Deutzia gracilis | rejuvenate when needed; head-back and renewal after flowering |
| Dogwood, gray | Cornus racemosa | head-back and renewal prune as needed; late fall or early spring |
| Dogwood, red-oiser | Cornus sericea | renewal prune every year for brighter stem color in early spring; rejuvenate over-grown shrubs |
| Euonymus, evergreen | Euonymus (fortunei) | prune anytime between February and mid-summer; major reshaping should be done before new growth begins in the spring |
| Euonymus, deciduous | Euonymus (alatus) | prune in late winter or early spring; renewal or heading-back method |
| Forsythia | Forsythia x intermedia | prune in late spring after flowers; use renewal and heading-back method; rejuvenate over-grown plants in early spring |
| Fothergilla | Fothergilla gardenii | dwarf and standard form can be pruned in late spring after flowers |
| Fringetree | Chionanthus virginicus | as a shrub remove unwanted stems; as a tree prune in early spring |
| Honeysuckle | Lonicera species | all honeysuckles respond well to all types of pruning in early spring or after flowers |
| Hydrangea, bigleaf | Hydrangea macrophylla | flowers on last year’s wood; prune after blooms (early August) to 6-to-8- inches; thin out old weak stems |
| Hydrangea, hills-of-snow | H. arborescens ‘Grandiflora’ | flowers on new wood; requires severe pruning in spring; cut back last year’s stems to within 2 buds of the ground just after growth begins |
| begins Hydrangea, oakleaf |
H. quercifolia | prune by heading-back in early spring |
| Kerria, Japanese | Kerria japonica | flowers on old wood; renewal prune older stems to ground to improve flowers; after flowering, remove some new wood for best stem color |
| Lilac, common | Syringa vulgaris | renewal prune after flowering; rejuvenate old shrubs in early spring |
| Lilac, Persian | Syringa persica | flowers on old wood; prune after flowering |
| Mockorange | Philadelphus species | flowers on old wood; renewal prune after flowering; rejuvenate in early spring |
| Privet | Ligustrum species | prune from late winter through summer; can be sheared |
| Quince, flowering | Chaenomeles species | renewal pruning after flowering, rejuvenation prune in early spring |
| Rhododendron, azalea | Rhododendron species |
little pruning is needed; renewal prune when dormant |
| Rose | Rosa species | roses may be pruned lightly or cut to the ground every year; climbers and ramblers: blooms in early summer on old wood, prune after flowering, leave new growth for next year hybrid bush-type: flowers on new wood; remove dead canes and cut back in spring; shrub roses: prune out old, diseased, or unwanted canes in spring, head-back after flowering |
| Rose-of-Sharon | Hibiscus syriacus | flowers on new wood; renewal prune to stimulate new growth at base |
| Snow berry | Symphoricarpos species | renewal prune in early spring; rejuvenate older plant |
| Spicebush | Calycanthus species | renewal prune to keep in shape; after flowering or in early spring |
| Spirea | summer-flowering Spiraea x bumalda Spiraea japonica | flowers in summer on new wood; prune in early spring before they leaf out; rejuvenation every two or three years in early spring |
| Spirea | spring-flowering Spiraea prunifolia, S. vanhouttei | flowers on old wood; renewal prune after flowering; shearing will remove flowers; over-grown plants may be rejuvenated |
| Viburnum, many | Viburnum species | renewal pruning and heading-back after flowering; older plants can be rejuvenated in late winter or early spring |
| Winterberry | Ilex verticillata | thin old growth to rejuvenate; heading-back in late spring |
| Weigela | Weigela hybrids | prune after flowering; renewal prune and light heading-back to keep in balance; can be rejuvenated |
| Witch hazel | Hamamelis vernalis Hamamelis virginiana |
flowers on old wood; renewal pruning and heading-back after flowering; can be rejuvenated flowers on new wood; prune in early spring |
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