Warm days and melting snow have gardeners looking longingly at their yard, wanting all the snow to disappear and the soil to become dry.
While waiting, look to see what needs to be pruned.
Starting with deciduous shrubs, divide them into two categories, ones that bloom before and after mid-June. Shrubs that flower before mid-June set their buds on last year’s wood. Pruning them before they bloom removes their flowers. Lilacs, forsythia, nanking cherry, double flowering plum, should all be pruned after they flower.
Shrubs are pruned to remove dead and diseased material, rejuvenate them and control their size and shape. If they are not pruned regularly they become very dense in the centre which blocks light from reaching any new growth. The result is either no new growth or deadwood from previous new growth in the centre of the plant. All the new growth goes into the top of the plant leaving it leggy or bare at the bottom.
Pruning a shrub is easy. Follow a few simple rules and the plant will respond with new growth, flowers and a pleasing shape.
Start pruning by removing all dead growth. Remember to cut back to the ground or another branch. Stubs are unattractive and hard for the plant allowing insects and diseases to enter the plant.
Once the dead and diseased material is removed, look at the plant. Is it leggy? Is there new growth at the base of the plant? If not, count the stems and remove up to a quarter of the stems back to the ground. If possible, remove the larger or older stems. When counting stems for removal, one large stem might be equivalent to two smaller ones.
Branches that cross each other are a problem as they rub and develop wounds and should be removed. Take out the ones that are facing inwards towards the center of the shrub.
Depending on the location of the shrub, it might also be important to lessen the height of the plant. Plants should not block driving visibility, grow over windows or block paths.
When pruning to reduce a plant’s size, cut back to another branch at the desired height.
When pruning, keep an eye on the brush pile and stop removing live branches when a quarter of the branches have been removed. More can be removed in following years.
Removing more branches are unlikely to kill the shrub but it will react by sending up an unusually large amount of new growth or watersprouts which will consist of many 1 to 2 foot (30 – 60 cm) branches. The plant will continue to use the new growth to gather food late into the fall when they will freeze and die and need to be removed the following spring.
The basic rules for pruning shrubs are: remove diseased or deadwood, remove branches that are crossing, always cut back to the ground or another branch and do not remove more than a quarter of the plant in one year.
Linda Tomlinson is a horticulturalist that has gardened in central Alberta for over 20 years. She can be reached at firstname.lastname@example.org.