The frequency of watering will depend on the month and the temperature. If there is little or no rain, it is recommended to water the cedars twice a week for the months of April, May, June, September, October and November for about two to three hours. In case of heat waves during July and August, it is recommended to water a third time to ensure that the hedge does not run out of water. Watering with a drip hose is highly recommended to ensure that water is evenly distributed throughout the hedge.
If the foliage inside the hedge turns yellow in August or September, it is probably a phenomenon called "hardening off". This is a normal process during which the cedar gets rid of its old foliage to make room for the new growth that will appear in the spring. If the cedar's foliage is yellow on the outside of the cedar as well, it could be transplant shock, overplanting or lack of water.
A White Cedar hedge will reach a height of about 40 to 50 feet while a Nigra Cedar hedge will reach a maximum height of about 20 feet. The size of a mature hedge will therefore be determined in most cases by the maintenance established by the owner.
Yes, a cedar will survive in the shade. However, its growth will slow down and its foliage will be thinner.
In the case of a Nigra or White Cedar (Thuya Occidentalis) hedge, the hedge will grow about 1 foot per year under good conditions. The speed of growth will be influenced by the amount of sunlight and the maintenance that the hedge receives.
A cedar hedge must receive a minimum of 2 to 3 hours of sunlight per day, be watered abundantly about twice a week (especially during heat waves), be pruned every year and in the best of worlds be fertilized as well.
If a hedge is left untrimmed each year, it will tend to grow about a foot and expand a few shoots per year. While it is possible to trim back a hedge that is too high, it is unfortunately impossible to thin out a hedge that is too wide. Therefore, annual pruning will ensure that the hedge does not become cumbersome in the long run and that a section of your land is not lost unnecessarily.
In the best case scenario, a cedar hedge should be trimmed every year. If the hedge is maintained every few years, the hedge will grow a few inches wider each year, which could lead to a wall several feet wide in the long run (not desired). If the cedars are never pruned, after a few years the snow will damage the branches which will become too long and heavy, and the hedge will slowly wither.
A hedge can become "rusty" for a number of reasons. If the cedar has just been planted, it is probably transplant shock. If a section of the hedge looks burnt throughout, it may be salt burn (validate if water is leaking from a salt water pool). If the tips of the regrowth in the centre of the hedge appear to be dry, it may be cedar leafminer (insect pest). Finally, if the foliage inside the hedge turns orange and falls off, it is probably a phenomenon called "budding" (quite normal) during which the cedar leaves its old foliage to make room for new shoots that will appear in the spring.