Glenmere in mid-summer: Lots of lilies, not much milfoil

By Pamela Chergotis CHESTER — The stuff on the end of my paddle sure looked like Eurasian watermilfoil, the invasive aquatic plant that is supposed to be overtaking Glenmere Lake. But botanists say native milfoil is so similar to the invasive type, not even experts can tell them apart without a DNA test.

Even if it is the invasive type of milfoil, the plants were not much in evidence in Glenmere Lake last week, and their long fronds did not break the water surface. Apparently, by this time of year, the milfoil's small purple flowers bloom above the surface, but on this day there were no flowers. It just didn't look like the lake had a milfoil problem.

There were, however, plenty of lily pads, mainly the white water lilies (Nymphaea odorata) and yellow non-native water lilies (Nuphar variegata) native to the Northeast. Both attach to the lake bottom by long stems and create a tangly mat of leaves on the surface.

A small sliver of the lake is in Chester, where Glenmere Mansion sits on a hill high above the water. The rest is in Warwick. The lake supplies drinking water to the Village of Florida.

In recent years Florida officials have called for eradicating Eurasian watermilfoil with the herbicide fluridone (Sonar), in an effort to prevent the village’s water supply from being overtaken by the plant.

But ecological consultant J.G. Barbour found “no problem with water milfoil or any other plant species in any part of Glenmere Lake" when he visited the lake in June 2010. "There is certainly no current or pending threat or emergency from any invasive plant species. It is possible that observed levels of water milfoil represent maximum or near maximum potential abundance at Glenmere Lake, and will not increase significantly.”

Barbour calls Glenmere an “exemplary” bog lake with an “exceptional diversity of aquatic plant species.” The lack of development around much of the lake contributes to its “high ecological quality,” he writes in his report.

He objects to the plan of adding chemicals to a drinking water supply. If Florida must do battle with milfoil, he suggests using the native milfoil weevil, an herbivore that would rather nibble Eurasian water milfoil than native species.