No reason why not - except they go light brown as they die back, so just look like a pile of dead leaves you've not bothered to clear away, and they're very unpleasant to handle, even when completely dry and dead.

I thought that they would keep wild life (deer squirrels etc) away

They keep cats off and probably foxes, anything with sensitive pads on the feet, doubt they'd stop deer, might be worth a try.

Thanks

If you need to do any weeding they are the devil to work with, though.

Thanks for the answers. What I was really worried about was whether any thing harmful would leech through into the soil and plants as the leaves degrade.I wouldnt be importing them, my garden on one side is surrounded by holly trees and bushes and the beds in question get covered any way but at present we rake them up. It just struck us that if we left them where they were they could act as a mulch and wildlife deterrant!

No, nothing harmful leaching out.