I have always sprayed undesired weeds and grass after it has come up. I would like your input concerning pre-emergent herbicides. Is it safe to use in any kind of landscaping with young trees, bushes, and flowers. From what I understand, pre-emergents go after the seed and anything that already is above ground is "safe" from it. Is this true? How close can it be applied to bushes, trees, etc.? Does it have to be watered in? What time of year is it applied? Any input you can send my direction would be appreciated!! By the way, we're in Wyoming where it doesn't rain!!!!