Aquatic weeds can be a huge problem for the property owner. If you use your lake primarily for recreational activities, lake weeds can put an end to your fishing, and other water sports in a matter of weeks if the wrong conditions exist. A lake weed invasion can also cause other problems, like pests in general, and mosquitoes in particular.

What is the best way to handle lake weed problems?

That depends on the nature of the problem. If the problem is an overly fertile body of water, you will need to lower the fertility.

Too much fertilizer

Excess fertility can be caused by nutrient runoff ending up in your lake. These nutrients can come from agricultural sites like adjacent farms and ranches existing upstream from your lake, or from over fertilized lawns in your area, which could even be your own.

Low fertility.

Low fertility means that the pond or lake is not getting the nutrients it needs to produce plankton. If plankton is not produced in sufficient quantity to tint the water enough to keep light from penetrating to the bottom, light will reach the bottom, and plants will grow up from it. This includes the filamentous algae that is often seen floating on a lakes surface.

Shallow lakes

Is your pond or lake so shallow that lake bottom gets light, weeds will grow. The best way to solve this problem is by either raising the water level if possible, or dredging.

Weed types

You should also know which category your lake weeds fall into. Are they submersed, emergent,  floating, or algae. There is a difference when it comes to treating them. There is a great tool from Texas A & M to help in the identification process. It is called Aquaplant. Aquaplant is also an excellent example of what a website should be!

Methods of aquatic plant control

Prevention:

This is the very best method for controlling any situation. If you can prevent it, you won’t have to control it or manage it in other ways. It just makes sense.

Biological control:

Most environmentally aware individuals prefer biological controls to chemical controls. There are some problems with that idea. Biological controls can be unpredictable, and run the risk of getting out of control if conditions should change. After all, you are adding another invasive predator into the mix!

Mechanical control:

Mechanical controls are great for some aquatic weed work, but not for all. Many aquatic weeds can reproduce from fragments at rates higher than fifty percent!

Unless you are resigned to mowing your lake as you do your lawn, it is a bad idea to fragment the living plants. If they can be cut smoothly, without much fragmentation causing vibration, and completely collected , that is great, but the problem will return from the roots.

Chemical Controls:

Sometimes, in fact, most of the time, the best weed management method, the most eco friendly method after prevention, is chemical lake weed control. It can, and should be, selective.

Aquatic weed control chemical types

Chemicals for controlling and managing aquatic weeds, fall into two categories:
Contact, and Systemic.

Contact Herbicides

Contact herbicides, work quickly, and kill all the vegetation they touch.

Systemic Herbicides

Systemic herbicides, work more slowly, but travel to the root of the plant to kill all parts of the plant.
Which one should you use? That depends a lot on the conditions, and the plant you are trying to get rid of. For more information on lake weed control types see:

Lake Weed Prevention

Biological Lake Weed Control

Mechanical Lake Weed Control

Chemical Lake Weed Controls