Late winter to early spring is a terrific time for pruning many shrubs. What should you prune and when? You could study pruning for an entire semester, but here are some basic guidelines. I recommend that you properly identify, then research, each particular kind of woody plant before you consider your first cut:
- Safety first 1) If any part of a tree or shrub is within ten feet of any kind of electric cable or wire, stop and call a professional. 2) Wear gloves and sturdy shoes, and use only sharp tools like bypass (not anvil) hand pruners and loppers, and saws. 3) Sanitize your tools and gloves with isopropyl alcohol or a product like Lysol spray before you start, and again when you’re done pruning each individual plant.
- General concepts Notice the overall shape of the shrub. Most flowering shrubs should be balanced and open in their center. Start pruning by removing all dead and diseased branches, then look for branches that cross or touch each other. Rubbing branches damage the bark tissue, inviting pathogens and pests, so remove one or both branches, depending on their condition, all the way to the base. Branches that grow from the perimeter towards the center should usually be removed. To shorten a branch or twig, cut it 1/4 inch above an outward-facing bud so new growth heads towards the perimeter of the shrub.
- When does your shrub bloom? 1) For spring bloomers, pruning them during the late dormant period (late winter/early spring) will remove flower buds, which were formed last year after the shrub bloomed. No flower buds, no flowers, so wait until after they bloom this year. 2) For later bloomers, pruning them now, before they form this year’s flower buds, is ideal. These can also be pruned soon after blooming.
- Roses Relax. Roses are simply shrubs that benefit from annual pruning. Prune in late winter to early spring (late dormancy) or when the buds start to swell. First cut out dead, broken, diseased and crossing canes. Put all your pruning debris in a trash bag and throw it away. Do not compost. Fertilize your roses with something like Espoma Rose-Tone or a good organic slow release fertilizer by following the directions on the bag. Climbers like to keep their main stems, so keep them fresh by pruning their lateral branches. Once the main stems are three years old, consider cutting one or two of them to their base to encourage new ones. Then cut one or two of the oldest every year. For shrub roses, cut up to 1/3 of the canes, the oldest, thickest woody ones, to their base as you open up the overall look to a vase shape. Cut to their base any super skinny canes from last year. For height, cut the remaining canes to about 1/2 their height, 1/4 inch above a robust outward-facing bud.
Please feel free to contact Carol with any questions.
Why didn’t your hydrangeas bloom this year? Most likely they were either pruned at the wrong time of year or their flower buds were damaged by winter weather or foraging deer.
With so many species and numerous cultivars, hydrangeas confuse many gardeners and even landscape designers when it comes to understanding the best time of year for pruning. Many gardeners prune at exactly the wrong time, eliminating almost all flower buds for the entire season.
Most early blooming shrubs, including some hydrangeas, develop their flower buds during the summer and fall of the previous year. This is known as blooming on old wood. Other hydrangeas develop their flower buds in the spring every year, then bloom later in the season. This is called blooming on new wood. Hydrangea cultivars such as Endless Summer™ bloom on both old and new wood.
Panicle hydrangea (Hydrangea paniculata) and smooth hydrangea (Hydrangea arborescens) develop their flower buds on new stems (new wood). Therefore they can be pruned back severely in the late fall or early spring to manage their size, and they will still provide flowers. Even after exceptionally cold winters where stems are killed to the ground, new spring stems will produce flowers. In our climate and soils, panicle hydrangea and smooth hydrangea are typically the easiest species to grow and provide the best show. Panicle hydrangeas, for instance, can bloom from July through October.
Common panicle hydrangea cultivars include: Limelight’, Vanilla Strawberry, Little Quick Fire, ‘Grandiflora’ aka PeeGee, ‘Fire and Ice’, Bobo®, ‘Bombshell’, ‘Little Lamb’, Quick Fire®, ‘Pee Wee’; Pinky Winky®, ‘Praecox’, and ‘Tardiva’. You can recognize them by their cone-shaped flower heads.
Common smooth hydrangea cultivars include: ‘Annabelle’, Invincibelle Spirit®, Incrediball®, and ‘Grandiflora’.
By contrast, hydrangeas that bloom in the spring bloom predominantly on old wood from flower buds that were formed during the previous summer and fall. They include bigleaf hydrangea (Hydrangea macrophylla), oakleaf hydrangea (Hydrangea quercifolia), mountain hydrangea (Hydrangea serrata) and climbing hydrangea (Hydrangea anomala subsp. petiolaris). These varieties should be pruned immediately after the flowers start to fade. You can cut off the just the flowers or cut the stem at any point you need to in order to control the size and shape of the shrub. If you prune later in the year, you’ll be removing next year’s flower buds.
If you know the type of hydrangea you have in your garden, it can take some of the mystery out of understanding why they’re not blooming as you expected, and knowing when to prune them. If you do not know what type of hydrangea you have, do not prune them. Remove only the dead wood in spring, then wait until they bloom to determine when to prune them the following year. If they’re planted in a favorable position in your landscape, they’re well worth waiting for.