Please advise the treatment of unwanted vegetation in spring fed pond....

Asked July 4, 2016, 8:30 AM EDT

Please advise the treatment of unwanted vegetation in spring fed pond. Grasses and weeds some cat tails. Algae currently not a problem, just weeds and grasses. Thanks so much

Licking County Ohio

1 Response

Greetings anonymous,

Much will depend on the plant species present. You'll want good identification on any of your targets because not all herbicides are universally effective at all times throughout the year on all plants. Please let me know if you'd like some help with ID.

If you consider using any herbicide, be certain you only use those products that are specifically labeled for aquatic applications and be certain to read and follow the label in all cases.

For broad-leaf emergent species growing around a pond, glyphosate is almost universal. However, depending on species, glyphosate application may need to be timed correctly to maximize effectiveness.

For example, as cattails are developing their seed heads early in the summer, they're pushing all their fluids, all their energy, into that reproductive effort. Treating them early may kill the exposed plant, but will leave substantial energy in the root system to regrow in future seasons. The best time to hit cattails is late in the summer, after that seed head has fully developed. At that time, the plant will redirect energy into the roots to survive the winter. Unfortunately, by that time, those leaves are tough, waxy, and difficult to penetrate, so you'll need to couple the herbicide with a good surfactant, usually as recommended on the label.

Many grasses and similar, narrow-leaf species are better controlled with formulae of imazapyr or newly approved topramezone. However, there are very few herbicides that are both effective on wetland grasses and highly selective for specific target species. That means that if you'd like some desirable species left standing among your targets (e.g., attractive sedges), those desirable species are likely to be affected as well.

. . . And good luck out there!