Our hedge is way overgrown, I'm not sure what types of trees they are, but they are about 4-5' wide. I want them really cut back, but in order to do that, we'll be cutting most of the greenery off. Will the greenery come back, or will I kill the trees? How far can we narrow them down?
Looks like it is probably a Thuja; if yes, I agree with Jimmyq that it won't resprout if cut back into brown stems. Can you post a close-up of the foliage?
I would almost guarantee they are Thuja occ. 'Smaragd' they and 'pyramidalis' are the two main culprits for 'cedar hedges' around here.
Any of these hedges that are other than tip pruned will not resprout. That is why when young you need to trim them as they grow to the shape and size you want. Then at least a yearly tip prune with shears or a hedge trimmer. I have recently had one pruned by the goats and it has definatley not come back. Around here when used as wind shields in paddocks they are planted with in two fence lines so the animals cannot get at them except trim them to the fence line. Liz
Given the magnitude of the replacement task, you could always try trimming them back as far as the green extends into the plant, and if they don't resprout, then replace them. Nothing ventured, nothing gained, and why take them out without trying first?
Thuja occidentalis 'Smaragd'. Wouldn't call a one-storey hedge "huge" but anyway agree that trying to work with it would be less of a drama than starting over. If managing living plants as a screen is not working for you then maybe will have to replace with a wood fence to maintain effect.
