Arborvitae Hedges - Care

Asked March 26, 2019, 5:54 PM EDT

We have arborvitae hedges in our backyard for privacy. They are a cedar variety and stand over 10' tall. We have very sandy soil here in Holland, MI, and we also live in a heavily wooded neighborhood, but still have ample sun that shines on the cedars. Since we moved here 5 years ago, we have never cleaned the accumulation of tree leaves from the base of the cedars (mainly oak and beech tree leaves). We have trimmed the hedges just once. They appear healthy, but may be thinning a little bit. Questions: #1 should we clear out the leaves, or leave them as is? #2 should we fertilize the bases if we clean out the leaves? #3 they appear to be spreading out from their bases (due to what seems to be an improper cutting before we moved in). Should we use ties to the base stems to get them to grow more upright and for their future growth and health? Any help and suggestions would be appreciated.

Ottawa County Michigan arborvitae arborvitae browning

1 Response

1. The leaves do help preserve soil moisture and as the leaves breakdown they add nutrients back into the soil. On the down side, they can also provide cover for voles to chew at the base. Check at the base of the shrub for damage. Since these shrubs look healthy, the leaves do not seem to be a problem.
2. If you are going to prune it would be appropriate to let the plant heal before promoting growth. Once you start seeing regrowth you may want to lightly fertilize but no later than mid July to prevent late growth that can be damage in the fall. If the plants look healthy there may not be any need for additional nutrients. Adding some compost may be all that is required.
3. Tying branches up may help but it should allow for movement and should be checked periodically and later removed if possible. Pruning back to a pyramidal shape allows more light and growth at the bottom and less mass at the top.

Check out the following links for additional information:

https://hort.extension.wisc.edu/files/2014/11/How-to-Properly-Prune-Evergreens.pdf

https://extension.unh.edu/resources/files/resource000594_rep616.pdf

I hope this is helpful,