The Art of Pruning: Timing and Techniques

Pruning is one of the best things you can do for your shrubs. Regular pruning maintains the shrub size and prevents breakage during the winter months by managing the structure. It even creates more flowers as the shrub redirects its energy into flower production rather than overgrowth.

The chart that follows provides our timing recommendations for pruning some of the most popular shrubs in our area. The “Flower buds” column notes whether the buds form on new or old growth, and the “Comments” column includes some of our gardener’s tips to successfully prune your shrub of choice.

For reference, here are the pruning techniques we recommend:

• Heading: Trimming long, unbranched stems by cutting above a healthy bud. This encourages lower branches to develop. • Rejuvenation: Cutting back all of the stems to within an inch of the ground during dormancy. Come spring, the plants will produce new shoots from the base. • Thinning: Removing selected shoots, or the main stem, to open up the middle of the plant to more sunlight. This maintains the natural form, keeps the interior branches healthy, and encourages new growth. • Shearing: Trimming the plant around the outside to restore structure in the landscape setting.

If you are not sure what types of plants are in your yard and whether or not they need pruning, bring a sample into our plant clinic, or take a photo and email it to us at [email protected]. We are happy to identify your plants for you.

Pruning Chart

Plant Name Best time Flower buds Pruning method Comments

Abelia Shape as needed in growing season. February - March New growth Thinning, Shearing Abelia x grandiflora Rejuvenate old plants.

Andromeda, Japanese May - June Old growth Thinning, Heading Prune after flowering. Pieris japonica

Aucuba March - April New growth Heading, Shearing Slowly rejuvenate old, leggy plants. Aucuba japonica

Azalea Prune after flowering. May - June Old growth Thinning Rhododendron spp. Rejuvenate overgrown plants.

Barberry March - May New growth Shearing Shape as needed in growing season. Berberis spp.

Bayberry, Northern May - June Old growth Thinning, Heading Prune to maintain natural shape. M. pensylvanica

Beautyberry January - February New growth Thinning, Heading Rejuvenate old, leggy plants. Callicarpa spp.

Plant Name Best time Flower buds Pruning method Comments

Annual thinning improves health and Boxwood February - March N/A Thinning, Heading density. Can occasionally shear Buxus spp. vigorous varieties.

Burning Bush January - March New growth Thinning, Shearing Shape as needed in growing season. Euonymus alatus

Butterfly bush Rejuvenate each spring. Deadhead March - April New growth Rejuvenation, Thinning Buddleia spp. spent flowers for rebloom.

Camellia May - June Old growth Thinning, Heading Slow to recover from heavy pruning. Camellia japonica

Camellia May - June Old growth Thinning, Heading Slow to recover from heavy pruning. Camellia sasanqua

Chastetree February - March New growth Thinning, Heading Rejuvenate old, leggy plants. Vitex agnus-castus

Cherry Laurel Prune just after flowering. Shape as May - June Old growth Heading, Shearing Prunus laurocerasus needed in growing season.

Remove dead branches and trim Cotoneaster Old and new February - March Thinning irregular growth. Shearing Cotoneaster spp. growth diminishes natural form. Crape Myrtle March - April New growth Thinning, Heading Shearing diminishes natural form. Lagerstroemia hybrids

Daphne, Winter April - May Old growth Heading Little to no pruning necessary. Daphne odora

Deutzia May - June Old growth Shearing, Heading Prune after flowering. Deutzia spp.

Dogwood, Red-twig Rejuvenate to encourage bright, March Old growth Rejuvenation, Thinning Cornus alba colorful stems.

Flowers and berries form on Firethorn previous year’s ‘spurs’. Retain as February - March Old growth Thinning, Heading Pyracantha coccinea many spurs as possible for berry production.

Forsythia Remove old canes annually to keep April - May Old growth Thinning, Rejuvenation Forsythia hybrid dense and full.

Fothergilla, Dwarf May - June Old growth Thinning, Heading Prune after flowering. Fothergilla gardenii

Heavenly Bamboo Thin a few older branches on tall March - April New growth Thinning, Heading N. domestica varieties to prevent leggy growth.

Holly February - March Old growth Shearing, Heading Rejuvenate overgrown plants. Ilex spp.

Hydrangea, smooth January - March New growth Heading, Rejuvenation Prune annually to keep dense. H. arborescens

Hydrangea, Big Leaf Remove dead branches and tips. March Old growth Thinning, Heading H. macrophylla Deadhead repeat blooming varieties.

Plant Name Best time Flower buds Pruning method Comments

Hydrangea, Panicle January - March New growth Thinning, Heading Can rejuvenate overgrown plants. H. paniculata

Hydrangea, Oakleaf June - July Old growth Thinning, Heading Prune after flowering. H. quercifolia

Jasmine, Winter March - April Old growth Thinning, Shearing Prune after flowering. Jasminum nudiflorum

Juniper Prune green tips only. Junipers will February - April N/A Shearing, Heading Juniperus spp. not regrow from woody stems.

Kerria May - June Old growth Thinning, Heading Thin old, leggy stems after flowering. Kerria japonica

Lilac, Common May - June Old growth Thinning, Heading Prune after flowering. Syringa vulgaris

Lilac, Dwarf Korean June - July Old growth Thinning, Heading Prune after flowering. Syringa meyeri

Loropetalum Old and new Prune in late winter, shape as February - March Thinning, Rejuvenation Loropetalum hybrid growth needed in growing season.

Mahonia Remove old, leggy stems in early March - April Old growth Thinning, Rejuvenation Mahonia spp. spring.

Mockorange Prune old, leggy stems after May - June Old growth Thinning, Heading Philadelphus hybrid flowering.

Mountain Laurel Prune after flowering. Rejuvenate June - July Old growth Thinning, Heading Kalmia latifolia old, leggy plants.

Ninebark Prune after flowering. Thin branches May - June Old growth Thinning, Heading Physocarpus opulifolius and head back outer growth ¼ - ⅓.

Thin branches in February - March. Photinia, Red tip February – March, Old growth Thinning, Shearing Shear tips in early summer to Photinia x frasier Summer maintain red tips.

Privet Shearing, Heading, Trim as needed through growing February - March New growth Ligustrum spp. Rejuvenation season.

Pussywillow April - May Old growth Thinning, Rejuvenation Prune after flowering. Salix caprea

Quince, Flowering May - June Old growth Thinning, Rejuvenation Prune after flowering. Chaenomeles spp.

Preserve main canes. Prune lateral Rose, shrub February - March New growth Rejuvenation, Thinning branches to promote flowering. Rosa hybrid Does not apply to climbing rose.

Rose-of-Sharon Prune vigorous branches as needed January - March New growth Thinning, Heading Hibiscus syriacus in the growing season.

Smoke tree January - March Old growth Thinning, Heading Rejuvenate leggy plants. Cotinus coggygria

Plant Name Best time Flower buds Pruning method Comments

Spirea, Bumald Old and new May - June Thinning, Shearing Deadhead for rebloom. Spirea x Bumalda growth

Spirea, Vanhoutte May - June Old growth Shearing, Rejuvenation Prune after flowering. Spirea x vanhouttei

Spirea, Japanese Old and new Shape as needed through the January - February Shearing, Rejuvenation Spirea japonica growth growing season.

Sweetshrub Old and new June - July Thinning, Rejuvenation Thin ‘suckers’ after flowering. Calycanthus floridus growth

Viburnum May - June Old growth Thinning, Heading Prune after flowering. Viburnum spp.

Virginia sweetspire June - July Old growth Thinning, Heading Prune after flowering. Itea virginica

Weigela Remove old, leggy stems and shape May and June Old growth Thinning, Heading Weigela florida as needed. Prune after flowering.

Winterberry Heavy pruning will diminish berry February - March Old growth Thinning, Heading Ilex verticillata production. Thin out leggy branches.

Witchhazel Remove ‘suckers’ in January. Thin March Old growth Thinning, Heading Hamamaelis spp. branches after flowering.