After applying approx. 25 bags of Preen Mulch Plus to the beds in my front yard, which include multiple Etain, Halo Blue Sky, Blue Moon, and Rebecca perennial violas, I looked on the Preen website and it did not say violas, violets, or pansies are "safe plants", but it did not list them on the "injury will occur" section. Realistically, will the pre-emergent harm my violas? They are well established plants. Has anyone used the Preen Mulch around violas?