Your hedge cedar, white or black, will only require an annual trim while providing you a screen all year while other varieties do not require trim at all.
In the case of a hedge that has been neglected, of large size, or that requires specific care, it is recommended to let an arborist do the work since he is a specialist. On the other hand, if your hedge has been well maintained, it is easy to trim it yourself.
The maintenance trim is practiced during the summer season, avoiding however periods of heat and drought. In addition, avoid trimming beyond the month of August. Late trim may leave wounds that could be damaged by winter winds and stimulate new growths that would not have time to fortify before winter.
Use a hedge trimmer after installing stakes and rope. This technique will allow you to make sure to make a straight line. Do not cut more than two thirds of new growths, which are distinguished by their soft green color.
A trim made in the rules of art should have a conical shape. The base is wider than the top so the cedar can receives enough light. It should also be noted that the summit should have a rounded shape. The beautiful straight and square hedges that we see in French gardens are perfect for … French gardens! Here, your hedge could be damaged by the weight of snow and ice.
The shaping trim needs to be done early in spring, when cedars are still in dormant season. If you need to shorten or even equalize your hedge in a major way, it is better to call a professional. The same is true for varieties that are less suitable for trim, such as ‘Smaragd’ (Emerald). You have probably chosen them for their size and shape so why complicate your life by trimming them!
Is it possible to shorten a cedar hedge by a few feet?
Since cedar foliage is difficult to regenerate of old wood, it is strongly discouraged to trim it beyond the new growths, either to reduce its size in height or width. We could have an unwanted effect on the plants, in addition to leaving them bare.
When you know that a white cedar can reach 12-18 meters in height and 3 meters in width, it is better to make sure to trim them every year than to risk having them cut because the size of your hedge has become disproportionate.
Naturally, if your hedge has reached the desired height, avoid fertilizing it!