Proper spacing of arborvitae
Our Emerald Green arborvitae were planted 24" apart 3 years ago. The planting card recommended 24" to 36" spacing but I've read recently that 5' is best! What conflicting information. We want these plants to provide privacy screening. They are sited well and growing well but we have become concerned that 24" is too close together for the long run. Will the trees suffer branch die back or other serious problems if kept at 24"? Should every other tree be removed to provide extra room to grow? Thank you!
Generally we don't want evergreens to grow together to the point that their canopies become misshapen. The general rule is to space them no closer than their mature width. The mature width for Emerald arborvitae is listed as 3 to 4 ft wide. So the recommendation would be to plant them no less than 3 ft apart, but wider is better. Once your plants begin to touch, you could remove every other one. That would decrease the chances of disease problems.
I recently wrote an article on this subject that you may view here: http://scliving.coop/home--garden/better-green-screens/
Thanks for your response. I read your article and found it helpful. Re: my plants, I didn't mention that I would be pruning these to remain at 5' - 6' in height. This is the general rule in our HOA for hedges planted in the front of homes. They are not touching yet. As I understand, this variety grows to maturity at 10' - 12'. My follow up question is would it be ok to leave the plants at their current 24" spacing if they are regularly pruned to remain at 5' - 6' in height? Thanks for your input!
If you are also pruning the sides also to maintain width so that they don't grow together, it will probably be ok. For spacing concerns we're more worried about the width than the height. However, be careful to avoid shearing, which will cause the plants to develop a thin layer of dense foliage at the surface. This will also create a situation of poor airflow leading to potential disease problems. Thinning as a pruning method to maintain an open plant is more desirable. See the links below for more info.
Thinning the Canopy