Thuja ‘Green Giants’ pruning


Hi….we have a hedge of Thule “Green Giants” we planted because we needed a rapid growing hedge…which we now have.
But we want to stop the vertical growth as they are becoming trees and difficult to prune at their sides near the top.
Can we just remove the leader from each one individually…(.don’t want to shear the tops off ).
Will removing a foot or so from each top stop the vertical growth and help keep the rest of the hedge full and dense.
The sides are not sparse but there are areas that have “holes”.
I have attached photos.
Thank you in advance for your advice.


Thuja ‘Green Giant’ is a hybrid arborvitae that is often chosen for its hardiness and as a privacy screen.  This variety of Thuja is well suited to a hedge-style trimming.    Arborvitae will withstand relatively heavy pruning and shearing because new branches develop from concealed buds in the branch crotches.  It is best to prune either in early spring before new growth emerges, or late summer/early fall after the new growth has hardened.  Avoid trimming during the hottest part of summer.  You can trim with either manual or electric hedge trimmer.

To ensure that your entire hedge gets access to sunlight, you should trim your trees in a “wedge” shape so that the base is wider than the top with a gentle slope.  If you trim complete vertically, then the lower branches won’t get as much light and will eventually thin out.

You can shear the tops of the trees round or flat, but don’t remove more than 20% of the height of the tree in any one year.  A rounded top will help deflect heavy snow in the winter.  While their height can be controlled through shearing the tops, the trees will continue to grow in height, so you may need to trim them every year or so.

It’s important to only cut into live wood (wood with green shoots).  Wood that is bare already will never grow new shoots, so if you cut too deeply on the sides or top you will be left with bare patches.