I have 3 golden tipped Thuja occidentalis shrubs that have grown straggly behind the shade of a kousa dogwood. Could I drastically cut these cedars down this spring and expect them to regrow slowly back? Not sure if gold coloured cedars will live through such an ordeal.
Thank you for your question.
Pruning is an excellent way to maintain shape, and removing some of the top growth can assist in promoting fuller growth by allowing sun to reach the lower the lower branches. Thuja are one of the evergreens that can generally withstand a heavy pruning – for more information on pruning the following links to a previously asked question on this topic and the Morton Arboretum website are helpful:
https://www.torontomastergardeners.ca/askagardener/thuja-green-giants-pruning/
https://www.mortonarb.org/trees-plants/tree-and-plant-advice/horticulture-care/pruning-evergreens
I am not sure which cultivar you have but pruning would be similar for all of them.
However, arborvitae need at least partial sun, and if the reason for the straggly growth is the shade of the dogwood even a heavy shearing is unlikely to afford the results you would like. It sounds like your plants may be reasonably small as you describe them as shrubs and they are shaded by the dogwood. If this is the case, you may wish to consider transplanting them to a more suitable location. If this is an option, the answer to a previous question provides some useful transplanting links:
Good luck with rejuvenating these beautiful plants!