Know When to Prune

By Jos Van Hage

    The reason we prune trees and shrubs is to encourage new growth and to direct growth to areas where the growth is uneven or sparse, thus creating a full even shaped plant.

Pruning out some of the inner branches will also create better air circulation, which in turn will reduce the chance of fungus and disease. Pruning out any dead, diseased or damaged branches will also help prevent any disease or fungus from taking
hold.

Pruning is done during the time of year when the plant can recover best, as well as when the plant blooms. The majority of pruning on deciduous trees and shrubs is done in spring when the leaf buds begin to swell. There is, however, a group of shrubs that are pruned later in the season, after they have finished blooming, and these are pruned now. This group is early spring/summer bloomers, which are those shrubs that bloom first before they get leavess. To prune them in spring would be pruning out any potential flowers as they form the following year’s flowers over last year’s summer.

This group includes Caragana, Cotoneaster, Hawthorn, Daphne, euonymus, Forsythia, Mock orange, Bog Rosemary, Flowering cherry, Rhododendron, Currant, Spiraea x vanhouttie, Lilac, Viburnum, and Weigela. Birch, Maple and Walnut trees are pruned in the second or third week of July when the sap has stopped running.

Ornamental trees do not need to be pruned yearly. Some years they may need to have more pruning done, while other years they may only need very little. You should always break off root suckers which are those young shoots that sprout from the main trunk of the tree at ground level. Root suckers take away needed nutrients from the main tree and serve no purpose. You want to break them off rather than prune off, otherwise they will grow back again. These can be removed anytime during the season.   

Another group of trees and shrubs that are pruned in the next couple of weeks are evergreens such as junipers (spreading and upright), spruce and cedar trees. These are pruned to keep them evenly shaped and full looking. The low growing junipers often grow more on one side than on the other so by pruning the new growth all around they will grow more evenly and fill out in the center. Cedars and Spruce trees only are pruned in this year’s or last year’s growth as they do not produce new growth on old branches. On these you would shear the new growth so that it becomes full and evenly shaped.

Do not forget to continue fertilizing trees and shrubs throughout the summer with a tree shrub fertilizer and an evergreen fertilizer for the evergreens! Do this until mid-August which is when you want the tree/shrub to prepare for winter. Also with the dry, hot weather we have had recently you want to keep on the watering, which is especially important with newly planted trees and shrubs as well as all cedars.

-Jos

Jos Van Hage owns and operates thre Art Knapp Garden Centres in the Prince George Region:

-Highway 16 West

-Highway 97 North

-Highway 97 South at the old Cariboo Highway

Email | Print | Facebook | Twitter | Digg | Del.icio.us