Prune trees, shrubs, and flowers for healthier plants
Many trees, shrubs, and perennials can produce more blooms and stronger growth if they are repotted at certain points in the year. The best window depends on the type of plant. Take the mystery out of when to prune all your plants with this guide.
1. Getting started
A good starting point for pruning any plant is to remove dead, diseased, or damaged stems as soon as you see them. Dead stems attract insects and invite disease to develop. Remove cross branches, water sprouts (vigorous upright shoots that develop on stems or side branches), and suckers (vigorous shoots that grow from the ground or below).
2. When to prune hydrangeas
Many hydrangea varieties, including bigleaf and oakleaf forms, bloom on old wood. Prune these types of hydrangeas before midsummer. If you prune them in winter or early spring, you will remove the flower buds. In newer regenerative varieties like the Endless Summer Series or the Let's Dance Series, pruning is less important because these hydrangeas bloom on new growth and old wood. Even if you prune old stems and cut off some flower buds, the plant will bloom on new growth.
White-flowered paniculata (varieties such as 'Beige' and 'Limelight') and arborescent varieties (including 'Annabel') bloom on new wood, so they can be pruned at any time except before flowering.
3. Spring-flowering trees and shrubs
Early spring flowers such as lilacs, forsythia, and rhododendron produce flowers on wood formed the previous year. The best time to prune them is late spring, right after they bloom. If you prune them during the growing season or in winter, you can remove flower buds and reduce the amount of blooms in the spring.
Test Garden Tip: To encourage vigorous spring bloomers, remove some of the old shoots from the ground. This allows the young stems to grow and flower.
4. Summer flowering trees and shrubs
Summer-blooming plants, such as potentilla and crape myrtle, produce their flowers on new growth from the current season. Prune them in winter when they are dormant or in early spring before they put out their new growth. You can cut them to the ground in late winter and they will still bloom in the same summer.
Test Garden Tip: Save time by using a pole pruner with a rotating head to remove stems all the way to the base of the plant. That way, you won't have to bend over for every cut, not just time, but wear and tear on your back!
5. Shrubs without showy flowers
Except for late fall, deciduous shrubs like the golden smoke tree shown here are grown primarily for their foliage. New growth initiated after late-season pruning may be too tender to survive the winter. If you want to do big pruning, it is better to cut back the bush when it is dormant in the winter.
6. When to prune clipped hedges
For shrubs such as boxwood, cut new growth frequently early in the growing season to maintain their size and shape. Keep the top slightly narrower than the bottom so that the upper branches do not shade the lower branches. Stop cutting hedges six weeks before your area's average first frost. Late winter to early spring or mid to late summer are the best times to prune hedges more severely.
Test garden tip: If you're growing a privacy hedge, minimize the amount of maintenance required by selecting shrubs that grow tall and wide enough to provide screening. Allow them to grow in their natural form and you won't need to prune as often.
7. When to prune roses
Treat climbing roses and old garden roses like other spring-blooming shrubs that bloom only once a year: Prune them after they bloom. Repeat bloomers, including hybrid teas, floribundas, grandifloras, miniatures, and modern shrub roses, are often pruned to shape the plant or to remove winter-damaged stems (shown here). If they overgrow, cut them back in early spring.
8. When to Prune Fall Shade Trees
Prune shade trees such as oak, linden, and ash when they are dormant in winter. The branch structure is easier to see at this time of year, and diseases are less likely to spread through pruning wounds. As with non-flowering shrubs, do not prune them in late summer.
Test Garden Tip: Trees that produce the most sap flow when pruned in winter — maples, birches, elms, and dogwoods — are called "bleeders." The sap flow may be unsightly, but it will not harm the tree. Prune these species in summer until the leaves are fully expanded to avoid bleeding.
9. When to Prune Deciduous Fruit Trees
Apples (including crab), peaches, pears, plums, and cherries should be pruned in mid-winter. Although winter pruning removes some of their flower buds, the goal of pruning fruit trees is to open up the tree to allow more light for the best fruit, rather than maximum flowering. Passive pruning is especially important for apples, pears, and crabapples because cuts during the growing season expose the trees to a bacterial disease called fireblight.
Test Garden Tip: To control the spread of diseases when pruning, soak your pruning shears in rubbing alcohol or a solution of one part bleach to nine parts water.
10. When to prune broadleaf evergreens
Most broadleaf evergreens, including holly, mahonia, and some types of magnolia, don't need much pruning. The best time to prune them is in early spring when they will increase their growth. Minor shaping and pruning can also be done at other times of the year.
Experimental Garden Tip: Cut some branches for winter holiday greenery and save them for holiday decorations.
11. When to prune needle-leaf evergreens
Most trees and shrubs with needle-like or scaly leaves (spruce, juniper, cypress, arborvitae, fir, yew, Douglas fir, and false cypress) are best pruned early in the growing season. Avoid cutting back a tree without green needles; It may not sprout new growth. As with broadleaf evergreens, trim the tips of some branches in mid-winter to bring some greenery indoors.
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