The Why and How of Shrub Pruning

Spring is filled with many gardening tasks including pruning shrubs. But before starting, be sure to have a good reason (and a plan), other than a date on the calendar, before making the first cut with the pruners. 

Pruning is an effective way to bring overgrown shrubs down in size and remove dead, damaged, crossing or rubbing branches. It can also be used to increase flowering and fruiting and intensify bark color.

Always use the best tool for the job. Use bypass hand pruners and loppers that make clean cuts, allowing the wounds to close quickly. Pruning saws are the best option for larger stems. Be sure to wear safety glasses when pruning to protect the eyes and gloves to protect and support hands.

Late winter/early spring, before growth begins, is a good time to prune summer-flowering shrubs like spirea, potentilla and Annabelle-type hydrangeas. It is easier to see what needs to be shortened or removed before the leaves sprout. Wounds also close more quickly and fewer insects and diseases are present, reducing the risk of infection.

Avoid pruning when buds break and leaves are expanding, as the bark is more subject to damage. Pruning as leaves emerge, or right after, wastes energy the plant stored and used to start a new season of growth. Also, avoid late summer or early fall pruning that can stimulate late-season growth which can be damaged over winter.

Photos courtesy of MelindaMyers.com

Wait until right after flowering to prune spring flowering shrubs like lilac, forsythia and bridal wreath spirea for maximum bloom. These can be pruned during the dormant season but some or all the flower buds will be removed, diminishing the spring floral display.

Match the pruning method and timing for evergreens. Avoid late summer and fall pruning that exposes inner needles and leaves that have been previously sheltered from harsh weather conditions. For pines, remove one-half to two-thirds of the expanding buds, known as candles, to limit new growth. Prune spruces above outward-facing healthy buds and junipers by removing or cutting back individual branches to healthy adjoining branches as needed. Yews can be pruned in early spring and lightly again in midsummer to remove any wayward branches.

Winter-damaged arborvitaes may need some pruning this spring. Remove broken branches but wait for bent branches to return upright. What also can help is loosely tying the stems upright and together with old nylon stockings, strips of cotton cloth or similar materials. Avoid topping arborvitaes, as that can increase the risk of future snow load and ice damage.

Shorten stems with heading cuts made one-quarter of an inch above an outward-facing bud or where a branch joins a shorter healthy branch. Prune damaged and diseased stems back to healthy outward-facing buds and branches or the soil surface on suckering shrubs.

Proper pruning can help renew or rejuvenate overgrown suckering deciduous shrubs like lilac, forsythia and red twig dogwoods. Start by removing one-third of the oldest and largest stems, including those that are damaged or diseased, back to ground level. Red twig dogwoods make it easy, as the older stems are brown and the new growth is bright red. This type of pruning stimulates new leafy growth. Repeating over the next two years will result in a shorter shrub with newer growth covered with leaves from the ground up.

More severe pruning is an option for suckering shrubs tolerant of that type of pruning or those that are declining or in need of major rejuvenation. This is done by pruning all stems close to ground level. This type of pruning often results in an even taller plant than before. The following year, remove as much as three-fourths of the new growth to ground level and reduce the height of the remaining stems as needed. Then prune as needed in subsequent years to maintain the desirable size and health of the plant.

Adjust the pruning method to reduce floppy growth on Annabelle-type hydrangeas, summer-blooming spireas and potentillas. Prune all the stems back halfway in late winter or early spring. Prune half of these to ground level. The older stems help support the new growth. Lightly shear summer-blooming spireas after flowering to encourage a second and third flush of blooms.

Photos courtesy of MelindaMyers.com

Pruning hydrangeas is based on flowering. Big leaf hydrangeas bloom on old wood and repeat bloomers, like Endless Summer, bloom on old and new growth. These often die back to the ground over winter in colder climates. Remove the dead branches and then pruning is complete for the season.

Oakleaf hydrangeas also set their flower buds the previous season. These need minimal or no pruning. If needed, prune right after flowering.

Panicle and Annabelle-type hydrangeas flower on new growth, so these can be pruned during the dormant season. Prune Annabelle-type hydrangeas back to ground level or as previously described.

Panicle hydrangeas, like limelight and Bobo, need minimal pruning. Remove damaged, rubbing and thin stems. Shorten side branches, if needed, leaving three to five buds on each stout stem. Severe pruning results in distorted and floppy growth.

Proper pruning can help boost the beauty and health of our backyard landscapes and shrubs. Make the right cuts at the right time for the best results.

Melinda Myers has written more than 20 gardening books including The Midwest Gardener’s Handbook, 2nd Edition, and Small Space Gardening. She hosts The Great Courses How to Grow Anything instant video series and the nationally syndicated Melinda’s Garden Moment TV and radio program. Myers is a columnist and contributing editor for Birds & Blooms magazine. For more information, visit MelindaMyers.com.

Learn more about the why and how of pruning hydrangeas and other shrubs with Melinda Myers at

11 a.m., April 20, at Pasquesi Home and Gardens,

located at 975 N. Shore Dr., in Lake Bluff.

The event is free and no registration is required.