Pruning Clinics Set for This Weekend

By Jos Van Hage

“When is the best time to prune trees and shrubs”, is a question that I am often asked this time of year. It depends on the weather but you want to prune deciduous trees and shrubs while they are still dormant but the buds on them are beginning to swell, which is a sign that there is life.

Not all deciduous trees/shrubs are pruned in early spring. The early blooming flowering shrubs such as Lilacs, Forsythia, Purple leaf sand cherry, and the Double flowering cherry are pruned after they have finished blooming. This is because they have formed this years flower last year and so the flower buds are already on the plant. To prune them in early spring before they bloom would mean that you are removing the flowers before they get a chance to bloom. These early bloomers are pruned right after they have finished blooming. Do not prune Maple, Birch or Walnut trees in early spring as these trees already have their sap running and to prune them now would seriously set them back or kill them. These are pruned in mid August when the sap is not running.

“Why to prune” is another question that is asked.

Not all deciduous trees and shrubs need to be pruned every year. Pruning is done to keep plants growing healthy, strong, nicely shaped, and produce a high quality yield of flowers, or fruit. You always prune out any dead, diseased, or damaged branches. If you are removing diseased branches make sure that you clean and disinfect your pruners after each cut so that you do not carry the disease to any other part of a healthy plant. You also want to remove branches that cross over each over and rub against each other.

On later blooming flowering shrubs you want to cut off all the old flowers from last year and trim the plant back into shape. Roses you want to fine tune your pruning as you should have done the large pruning last fall. On the roses you want to prune just above a healthy outfacing bud to make the new branch grow out rather than into the plant. This is because you want to keep the middle of the plant open to create good air circulation which in turn will prevent mildew and fungus. Shrubs such as the red twig dogwood should have 1/3 of the oldest stems cut out of it as this will promote new brightly colored stems which are one of the plants features.

“What to prune and when” may be another question. As mentioned all deciduous trees and shrubs with the exception of the early blooming flowering shrubs and Maple, Birch, and Walnut are pruned in the early spring.

Pine such as the mugho pine is pruned after the new candles have formed and then you remove the top half of the candle. This will produce a full looking, compact plant.

Cedars are sheared during the time they are producing new growth during the summer into the beginning of August. When you shear them you only cut into the new growth as the old growth will not reproduce new growth. Spruce trees are pruned only if they have lost their shape. Prune them in the first two weeks of July after the new growth has fully developed. If there are branches that are too low, these can be removed at any time.

One other important thing that should be done in the next couple of weeks for deciduous trees and shrubs while they are still dormant is spraying them with ‘Lime Sulfur and Dormant Oil’. This is a combination spray containing a fungicide/insecticide that will kill any of the over wintering insects and fungus. It is used as a preventive measure that could eliminate problems that occur over the summer months. To apply this you need to spray the plant before it breaks into leave and the weather has to stay above freezing for 48 hours, so there is a small time frame.

I always tell people “if you are not sure about how to prune, then you are better off not to prune as you can cause more harm than good by not knowing what you are doing”. It is a good idea to purchase a good pruning book, ask an expert, or come in and take the pruning course that is being offered at the garden center this weekend.

Pruning Clinic:

We are holding two sessions at the Art Knapp HWY 16 west location only. The first session will be Saturday April 5, 2008 at 10:00 a.m. and the second session will be Sunday April 6, 2008 at 1 p.m...

We have been doing these courses for over 25 years now and they have always been well attended. There is a $10.00 charge per person and this will be donated to the ‘Special Olympics’ this year.

-Jos

Jos VanHage owns two Art Knapp Garden Centres in Prince George

• Highway 16 West at Kimball Road
• Highway 97 North at Northwood Pulpmill Road

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