Plant Responses to ProcellaCOR


Sept 7, 2023

Najas minor (European Naiad) found near beach 6. A mere touch or wave near N. minor shattered the plant - seeds were still present. A few plants were removed with a hand net from the kayak, but it was very difficult not to cause fragments, so most were not removed.



Myriophyllum heteroplyllum (Variable Leaf Milfoil) is clearly stressed - the plants are lying down and looking browned, and blackened. It was easy to slide an entire rooted plant from the sediment to check on its status. There was no resistance.

Brasenia schreberi (Watershield) stems are exhibiting unusual spiralling modes, and the leaves appear to be burnt.

Native Najas (naiads) species we encountered were stressed and disintegrating. N. flexilis and N. gracillima leaves were decomposing, but the plant form remained intact, and seeds were seen.

Lilies and spatterdock leaves on the surface are very browned and many have decomposed into a mush.

There are many Pondweeds that look as if they’re unaffected by the herbicide near Brown Brook. There is a lot of Potomageton robbinsii, P. spirillus, P. epihydrus,  P. zosteriformis, P. perfoliatus and P. gramineus looking healthy. They are fruiting successfully in great numbers.

Utricularia (Bladderwort) species have not shown any visible signs of stress. There is an abundance of U. inflata and many U. vulgaris plants, though fewer than U. inflata. They appear to be unaffected at this point. U. radiata was not observed.

A few Elodea canadensis plants were seen, but did not appear to be stressed.

Callitriche palustris was in good condition, as was Ceratophyllum demersum, and Chara.

No crowfoots, water marigolds or native milfoils were observed.

Reeds and rushes at the water’s edge did not appear to be compromised by the herbicide




Sept 21, 2023

Launching from Beach 9 (Leisure Lane, Brown Brook Arm treated with ProcellaCOR - 08/29/2023) with 2 trained plant patrollers, we observed the following:

Three weeks after application, the Pondweeds appear to have weathered the herbicide way better than any other submersed plants at this point. There was an abundance of P. gramineus, P. epihydrus, P. ampilfolius, P. robbinsii and P. amplifolius. We also observed P. zosteriformis and P. spirillus in quite a few places. There was not much else growing in the plant communities where these were established.

There were few naiads to be found in the herbicided area that were still standing upright, and those that were had disintegrated to the point of being almost indeterminable. The leaves were fleshy and flimsy like wet paper.

We did not see any Milfoils thriving or standing up in the water column. Most that we lifted out were dark, waterlogged and disintegrating, with barely an entire whorl to be seen.

Also managing okay, and identifiable, was Eleocharis robbinsii and Sparganium americanum

Floating leaved plants: Nymphaea odorata, N. variegata, Pontederia cordata and Brasenia schreberi had floating leaves that still appeared viable. A fair number of the lilies had curled or rolled up leaves, but most were flat with some curved up and burnt edges. The Watershields exhibited some unusual extra coils of their stems.

Bladderworts did not appear to be impacted by ProcellaCOR, but perhaps this is because they are free floating and new ones can have floated in.