Answer: As you've seen, it is absolutely critical to follow label directions when applying any type of pesticide--herbicides included. Not only is it a good idea, environmentally and health-wise, it is also the law.
I found the following information on http://www.preen.com/homepg.asp, which appears to be the home page for the product (from the manufacturer of the product):
Q. If you over-applied Preen or Preen 'n Green or applied in an area not recommended for use, what can you do to correct?
A. Apply activated charcoal at the rate of 1lb. per 100 sq.ft. Lightly work into surface of soil. Water each day for 3 days. Wait 2 more days and the Preen and Preen 'n Green control will be neutralized.
If you have further questions, I suggest you contact the makers of Preen and request assistance from them directly.
Q&A Library Searching Tips