Pruning Basics for the Garden
As we get into the gardening season, many of us are anxious to get started on our outdoor projects. It can be tempting to throw on a jacket and get outside to enjoy the sun while working in the yard, but we need to have patience as the snow disappears and the ground thaws. One thing we can start to do is prune, but there are a few things to remember before pulling out the pruners.
The first thing you want to do is establish which plants need to be pruned and when.
Pruning is done for a few different reasons, it can:
· improve overall plant health by removing dead, diseased or tangled branches
· increase production of blooms and fruit
· rejuvenate or increase plant vigour by removing old growth
· control plant size
We’re going to provide some basic information about pruning flowering shrubs, perennials, evergreens and broadleaf evergreens below. This will provide some general information about pruning, but there are definitely exceptions to every rule. If you have specific questions, feel free to send us a note at email@example.com
, or best of all, visit us and maybe even bring in a photo of the plants.
Pruning Flowering Shrubs:
In order to know when you should prune your flowering shrubs, you need to consider whether they bloom in the spring or in the summer and fall.
Flowering shrubs that bloom in the spring actually bloom on the previous year's wood, and therefore must be pruned after they bloom - the best time being immediately after they flower.
Flowering shrubs that bloom in the summer or fall actually bloom on the current season’s growth. Therefore, these shrubs should be pruned in early spring, before new growth begins. If desired, they can be pruned again after flowering to remove the spent blooms.
Also, some mature plants may require pruning if they have lost vigour. If you’re pruning an old plant to rejuvenate it, you should prune away the oldest wood first, but never more than one third of the plant in a season.
Pruning perennials is mainly removing last year’s growth; an example would be ornamental grasses. They look beautiful when left to sway back and forth in the winter landscape, but in the early spring they should be cut back to allow the new growth to flourish. For the most part, woody perennials can follow the flowering shrub basics with a late bloomer being pruned in the early spring - an example would be Butterfly Bush. To increase the length of bloom time in your perennial beds always remove spent blooms to encourage more vigorous growth and lengthy blooming!
Pruning Broadleaf Evergreens
The main reasons for pruning non-flowering broadleaf evergreens are to shear off winter-burn and control shape. The best time to prune non-flowering broadleaf evergreens is in the spring.
If you have flowering broadleaf evergreens, it’s best to prune them immediately after flowering, as the flowers are set on the previous year’s growth. If you have Rhododendrons it’s important to remember to pinch off only the spent bloom, as next year's blooms are not far below.
There are two main types of evergreens; those whose branches radiate out from the main trunk (Pine and Spruce) and those with a more random branching pattern (Juniper, Cedar and Yew).
The first category of evergreen only require pruning to remove dead or broken branches, but can also be pruned if you wish to control their size or density. Pruning to control size or density should typically be done in mid-June, and you should not prune away more than about half of the new growth. (Spruce's new growth will be produced as buds along the branch. Pine's new growth will be produced only at the tips of the branches and resemble candles.)
The second category only requires pruning to remove winter-burn or broken branches, but can be pruned to control size or density. Winter damage can be pruned away in the early spring, and if you want to control the size and density (or create a hedge), they can be pruned again in early summer depending on their growth and how controlled you want to keep them.
Below is a list of some popular flowering shrubs with more information about when and how much to prune them, if they require it.
Shrubs to prune in the early spring before new growth starts:
· American Elder (Sambucus canadensis)
· Annabelle Hydrangea (Hydrangea arborescens)*
· Beautyberry (Callicarpa japonica)
· Bluebeard (Caryopteris)
· Bush Honeysuckle (Diervilla sessilifolia)
· Coralberry/Snowberry (Symphoricarpos)
· False Spirea (Sorbaria)
· Flowering Raspberry (Rhus odoratus)
· Flowering Quince (Chaenomeles)
· Pee Gee Hydrangea (Hydrangea paniculata)*
· Rose Of Sharon (Hibiscus syriacus)
· Saint John's Wort (Hypericum)
· Witch Hazel (Hamamelis virginiana)
*Mophead Hydrangea (Hydrangea macrophylla) is an often over looked exception. These should not be pruned as they bloom predominately on last year's growth, simply remove spent blooms at the tip.
Shrubs to prune immediately after flowering:
· Beautybush (Kolkwitzia)
· Flowering Quince (Chaenomeles)
· Forsythia (Forsythia intermedia)
· Honeysuckle (Lonicera)
· Japanese Rose (Kerria japonica)
· Lilac (Syringa)
· Mock Orange (Philadelphus coronaries)
· Ninebark (Physocarpus)
· Smoke Tree (Cotinus coggygria)
· Spiraea bumalda
· Spiraea japonica