We Have Very Close Two Row Of Leyland Trees. All…
Juan Asked
We have very close two row of Leyland trees. All branches between are very brown. If we pull out one row, we wonder if the dead branches will come back or we need to replace the trees.
The Gardener’s Answer
Hello, Juan in new Jersey: Spacing plant material in the landscape with their mature height and width in mind is essential in terms of good air circulation. Leyland cypress (Cupressocyparis leylandii) are susceptible to bagworms and various fungal diseases as well as damage during extreme wind and ice storms. With the foliage on your evergreens only being brown on the side where they are planted too close to the second row of evergreens, it sounds like the problem has more to do with lack of proper air movement. This is a nice environment for insects and disease to thrive so you should take a sample of the foliage to your County Cooperative Extension Service to have the horticulture agent look at just to rule out any other issues. Unfortunately, once evergreens lose their outer foliage it is unlikely that they will produce new growth to replace the lost growth, but really only time will tell. If it were the inner foliage turning brown, this would not be of concern since it is a normal part of an evergreen’s life cycle. This is especially true for the Leyland cypress because they are such fast growers that they need to drop some of their foliage in order to make room for new growth. At this point you should remove one row of the cypress and re-evaluate the damage on the ones you would like to keep. You will need to prune off all dead material and remove it from the area to discourage insects and other potential disease issues. If you intend on transplanting the second row of your cypress this can be tricky depending on how tall they are. These evergreens have a shallow root system, so if they are taller than 15-20 feet they may struggle to support themselves after being transplanted. Leyland cypress thrive when planted in full sun, at least six hours each day, and demand well-drained soil.
