Q: I would like to know if it would be harmful to put ground up tree leaves around my azaleas? My city gives away leaves they have picked up. Do you think it is safe?

A: When leaves are picked up from the street, there is always the possibility they might be contaminated with oil or antifreeze. I think, however, that the mixing of leaves in the vacuum truck will dilute any contaminants to a level that won’t hurt your plants. As long as the mulch layer is about an inch thick your landscape should be fine.