I have used preen frequently and have several pounds in the shed. I really liked it at first. I scattered it on my entire garden, though not on vegies. Thought it worked great. Considering I have waves of green normally of chickweed among other horrible weeds. Then last year I applied it and I had some oddities on a few plants. They (like Leopard's Bane) sort of grew twisted, contorted.) The only thing I could figure was the preen - perhaps I was too 'generous' with it in the pursuit of preventing weeds. So this spring I was very careful about using an applicator, like you would use to fertilize or plant lawn seed. Same problem. Also hit my delphiniums. Nothing else was obvious. Had weeds out the wazoo but I didn't reapply as perhaps I should. As the ground gets disturbed in tending the beds it turns up new weed seeds.
So not sure what to say other than use it judiciously. I really need to write to the preen people and ask them 'what'z up?" before next spring.
