Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Great if carefully used

This product is a great supplement to the physical weeding you have to do with a weedeater or other device. What you have to do is to spray the plant on Monday to let the toxin be carried to the root center. Then, on Wednesday, if you insist on whacking the weed and not just spraying, you can go and tear it down. It's crucial that the intact plant have 1 or 2 days to take in this product. If you cut if down and then spray it, you may well be spraying to no effect. It must be absorbed by a functioning leaf to really take effect. It does work, but you must take care. It's impossible to have a spray just for weeds; plants are plants, so if you misfire onto your prized shrub, you'd better spray water promptly to ensure its viability.