I have over a hundred feet of cedar hedges in a climate zone 5. The hedge is about 7 feet and is many years old. I have it trimmed annually …usually in June. Should I remove old leaves, pine needles and dead cedar leaves from under my hedge? Does it need airing or does this stuff keep the hedge healthy by proving shade to the roots?
It sounds as if your cedar hedge is very successful and healthy. There is no reason to clear out old leaves and other organic matter from underneath it. You’re right, this organic matter helps keeps the roots covered but it also offers the trees important nutrition as it breaks down into beneficial compost. The mulch that the old leaves provides also conserves soil moisture. If you want, you can speed up the decomposition process by shredding the leaves with a lawn mower and then putting them back under the hedge. But your hedge is doing so well, there’s really no need to change what you’re already doing.
Here’s an answer to another question about a cedar hedge: