I live in a neighborhood in CT where our 11 households own a 7-acre pond. Pond vegetation used to be waterlillies (2 types). Milfoil grew heavily ovr the last 10 years. We contacted a company called Pond and Lake Connection, one of their guys told us about ProcellaCOR, a new herbicide (modified plant growth hormone) supposedly very selective for Milfoil and other invasives at very low concentration, supposedly not affecting other vegetation or posing the problems more typical of herbicides.
We had it treated last summer at a one-time cost of about $6000. It worked, all milfoil died and within days not visible. But there was some damage to the waterlillies; many showed browning of the leaves and this spring lilly abundance had been diminished. Also we noticed some dead lily roots (rhizomes) floating in shallower regions where lillies grow, and some of these rhizomes bring with them mud to produce small floating islands of muck. So there were some unexpected side effects. We've been swimming and fishing in the pond this season; the water appears much cleaner and the fishing is good. We're still wondering about the muck islands, how long they will take to sink, at least one did.
