Weed Control TT92
Published on May 8, 2014

Weed Control TT92

The old joke goes something like this … “In a garden, when does a plant become a weed? When your wife says so.” In a pond or lake, when things start to touch your feet or rub against your legs, you decide something has to be done about the rapidly encroaching growth. But how do you take care of the problem and not damage your vacation fund or the environment?

First, how bad is the problem? Is it a seasonal one that invades your swimming area or do ducks on their annual fall migration make your pond or lake a mandatory stop? If it is an occasional problem, some physical removal with a Weedrake (Part No. AWR1) or Weedcutter (Part No. AWC) may be all that is needed to keep things under control. But, if the pond’s plant life grows like something out of a bad sci-fi movie, you will have to take more drastic action. This doesn’t necessarily mean chemicals must be used just yet, but it may end up there.

One of the more popular methods and the easiest to use with a wide variety of aquatic life are water dyes. These dyes create a colored water environment that limits sunlight penetration and effectively cuts off the plants’ ability to convert nutrients into food through photosynthesis. The terrestrial equivalent is like someone parking an R/V on your grass for the summer. These dyes can last as long as three to four months at full strength and are available in black and varying shades of blue. They are harmless to the environment and you can safely swim in the water without fear of turning into cartoon-character blue. (Be careful with application though. One of our clients was standing downwind of a large spray fountain on a windy day. He poured in the dye and watched in awe as the fountain turned a dark blue. Then the wind changed direction, and George looked like he had a case of blue measles!) These dyes will affect the good plants as well as the bad ones and using a “little” of the dye is as good as not using any when it comes to effective plant control.

A biological control that works very well is the use of a plant-eating carp, more specifically, the Russian Grass Carp or Amur. These carp are sterilized against breeding (so they won’t get out of control) and their high metabolism and preference for a wide variety of vegetation can effectively control a pond’s or even a large lake’s nuisance plant problem. Consult with your local Department of Natural Resources office or a wildlife officer to determine whether these fish are legal to stock in your state or county. And remember, these fish are not trained to eat only the bad weeds. Overstocking or poor management of their population could result in other problems like a shift from macrophytes (large leafy plants) to unicellular ones (algae). We’ve heard of overzealous pond owners exceeding the recommended stocking rates for their ponds and ending up with plant-free, pea-green water. The reason? The carp ate every plant in the pond and passed these nutrients back into the water for the opportunistic algae to feed on. This can set your pond’s management plan back years.

In many situations, nothing gets the job done quicker and more effectively than the use of an aquatic herbicide. The key to choosing the right product is identifying the type of plant you are trying to control. Without this identification, you may purchase an expensive herbicide that doesn’t work as well as another product that costs less. If there are no local experts to help you decide what type of plant you have, there are books (WQB2) and CD-ROMs (CD22) available. Once the plant species has been determined, it is a matter of carefully reading each product’s description. We’ve tried to include as much information in our catalog as possible to help you with your decision. However, only you can learn whether each product is permitted for use in your area and laws change faster then a bat’s flight plan, so consult with the appropriate authorities.