Pruning Basics
Most shrubs, evergreens and trees require some pruning, whether it be to maintain its shape and size, improve the plant’s general appearance or remove dead or diseased branches.
What to Prune
Whatever you are pruning, always use a solid, sharp set of pruners or pruning shears. Never use dull blades to prune your plants, as this may cause harm with uneven cuts.
When to Prune
For major pruning jobs, early spring is the best time to prune, except for spring flowering shrubs such as Forsythia, Magnolia, Lilac and trees which should be pruned after flowering. Shaping can be done later in the growing season. Broken and dead branches should be removed as soon as possible as these weakened areas allow easy entry for insects and diseases. Fruit trees should be pruned before the buds start to open in March or early April.
Trees
Generally, trees can be pruned throughout the year to maintain their shape and remove dead and diseased branches. However, Birch, Honey-locust, Magnolia, Mulberry, Maple and Linden can only be pruned in mid-summer as they bleed profusely in spring. Other exceptions apply such as Crab Apples and Lilacs. These trees should be pruned after they bloom. Large cuts on branches over 10 cm should be treated with pruning paint.
Roses
Only roses that have grown extremely tall, e.g. over one metre, should have their branches cut back to one metre in the fall to prevent ice damage. Hybrid Tea and Floribunda roses should be pruned in April after the buds start to grow, pruning just above a good, strong bud that points outward from the centre of the plant. Climbers need to have dead wood removed each spring and side branches that have just flowered pruned back.
Deciduous Shrubs
In early spring, remove older, thicker stems at ground level to rejuvenate the plant. This will allow light and air into the centre of the shrub to promote new growth. Shaping can be done later during the season after the shrub has flowered. Remember, some plants flower on new wood (this year’s
growth) and others on old wood (last year’s growth). Mock-orange, Serviceberry, Saskatoon, Forsythia, Lilacs and Deutzia produce flowers on the previous year’s growth and should be pruned after flowering. Summer flowering shrubs such as Annabelle and Peegee Hydrangeas, Potentillas, summer flowering Spireas, and Rose-of-Sharon should be pruned in early spring before growth begins.
Evergreens
Start pruning for shape when plants are young. Formal plants, such as Boxwood, can be trimmed several times through the year. Junipers should be pruned before the growing season and larger evergreens, such as Pines, when new growth is vigorous. Candles (the long finger-like growth on Spruce and Pines) can be cut in half before they open up and mature in mid-June.
