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Pruning your flowering Trees and Shrubs- When is the best time?

When you can't wait to get started in the spring garden, a good task to undertake is pruning. Most trees and shrubs benefit from annual pruning. It keep them in shape, gets rid of dead and diseased wood and encourages new growth. But not all trees and shrubs should be pruned early, especially some of the flowering ones.

Early spring bloomers set their flower buds the fall before. Pruning them early in the spring would mean losing some blossoms and is one of the most common answers to "Why don't my plants bloom?. Most of the time this is not what you want. However there are exceptions. It’s often easier to prune when you can see the shape of the plant, before the branches are masked by leaves. Trees and shrubs that are in need of a good shaping could sacrifice a few blooms to be invigorated by a spring pruning.

There are no hard and fast rules, but here is a of list of commonly grown spring flowering trees and shrubs and the best time to prune them.

Trees and Shrubs to Prune in Late Spring/Summer, After Bloom

Azalea (Rhododendron species)
 Beautybush (Kolkwitzia amabilis)
  Bridal Wreath Spirea (Spirea x vanhouttei)
 Flowering Crabapple (Malus species and cultivars) Forsythia (forsythia x intermedia)
Hawthorn (Crataegus species and cult
Hydrangea, Bigleaf (Hydrangea macrophylla
Lilac (Syringa vulgaris)
Magnolia (Magnolia species and cultivars
Mockorange (Philadelphus coronarius)
 Mountain Laurel (Kalmia latifolia)
Rhododendron (Rhododendron species)
Serviceberry (Amelanchier x grandiflora)
Slender Deutzia (deutzia gracilis)
Weigela (Weigela florida)

Trees and Shrubs to Prune in Early Spring, While Dormant

You can still get your pruner out this spring to shape the following list of trees and shrubs, while they are still dormant.

Bradford Pear (Pyrus calleryana)

Butterfly Bush (Buddleia Davidii)

Crape Myrtle (Lagerstroemia indica)

Flowering Dogwood (Cornus florida)

Flowering Plum (Prunus blireana)

Glossy Abelia (Abelia x grandiflora)

Golden Rain Tree (Koelreuteria paniculata)

Honeysuckle (Lonicera fragrantissiam)

Hydrangea, Peegee (Hydrangea paniculata ‘Grandiflora’)

Potentilla (Potentilla fruticosa)

Redbud (Cercis canadensis)

Spirea (except Bridal Wreath) (Spirea japonica))

Wisteria (Wistera species)

Question: Jimmie, Is there a general rule of thumb on trimming shrubs that have flowers certain times of year? Thank you so much for your help! I read all your columns and have learned so much! Nancy P. in Prosper.

Answer:  Hi Nancy, To answer the question of when to prune flowering shrubs, we must first determine the reason behind the pruning. Do you wish to rejuvenate overgrown, neglected bushes through pruning? Or is this to be merely a routine pruning to maintain the flowering shrubs within certain dimensions? We sometimes wish to prune flowering shrubs in order to shape them or keep them within certain bounds. But we worry that we'll miss out on this year's blossoms if we prune at the incorrect time. Here's the general rule of thumb to know when to prune a particular plant.

If you are undertaking a routine pruning, observe the shrubs' blooming habits. For shrubs that bloom in summer or fall on the current year's growth, such as beautyberry, prune in late winter or early spring. For shrubs that bloom in spring on last year's growth  (forsythia), prune after their blooms begin to die.

If you are pruning flowering shrubs to rejuvenate them, the best time to prune is late winter or early spring. True, pruning early-flowering shrubs at this time will reduce or eliminate blossoming in spring that year, but the trade-off is in gaining healthier, more vigorous flowering shrubs for the long run.

Question: Jimmie, When is the best time of year to trim Evergreen shrubs like Holly's? Thank you for your answer. Paul L. in Prosper.

Answer: Hi Paul, In general, prune needle-bearing evergreen shrubs in early spring, toward the end of dormancy and prior to emergence of new growth. Pruning evergreen shrubs at this time allows plenty of time for new growth to emerge, as well as plenty of time for these new shoots to harden off before the following winter. But you'll often wish to treat broadleaf evergreen shrubs (and some needle-bearing varieties) differently.... While, technically speaking, you may treat broadleaf evergreen shrubs in the manner described above, there are often reasons not to treat them as you would needle-bearing evergreen shrubs.

For instance, if they are flowering shrubs, you'll want to wait until after the flowering period to prune. Otherwise, you'll miss that year's blooms.

Moreover, for evergreen shrubs (whether broadleaf or needle-bearing) that comprise hedges, you may want to prune after their new growth has emerged in spring. It is, after all, mainly the new growth that affords opportunity for shaping (assuming, of course, that you've been maintaining the hedge all along). Among needle-bearing evergreen shrubs Holly is a popular choice for hedges, because it's amenable to pruning. Until next time...Happy Gardening!!


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