A: Simply put, fast. Duckweed grows more quickly than any other plant– under ideal conditions, duckweed can double in size overnight. With that in mind, it’s easy to see how duckweed in lake or pond water could rapidly become a problem. As duckweed covers the water’s surface, it blocks out sunlight and reduces oxygen, making it difficult for other plants and fish to survive.
Duckweed consists of light-green clover-shaped leaves that float on top of the water, primarily in lakes and ponds. Each leaf is approximately three-sixteenths to one-eighth of an inch in diameter and there is a small, thread-like root that dangles down into the water. Duckweed leaves tend to group together, forming dense colonies.
It is easy to confuse duckweed with watermeal, a similar nuisance plant. However, watermeal is a bit smaller, and the leaves are more rounded and seed-like. Watermeal also does not have a root attached.
How to Get Rid of Duckweed
If duckweed is starting to take over your backyard lake or pond, there are a few things you can do.
Mechanical removal is one option. This can be done with a rake or debris skimmer. Simply go over the surface of the water, removing any duckweed leaves along the way. The drawback to this method is that it is difficult to completely remove every leaf. Even a couple of leaves left behind can cause duckweed to regrow.
Herbicide is the most effective way to combat a duckweed outbreak. Aquatic weed control products such as Ultra PondWeed Defense and KnockDown Defense can help kill off duckweed and any other weeds that may be present. KnockDown Defense will also take care of floating algae, which may be impacting water quality and contributing to the duckweed problem. Combine an aquatic weed killer with Treatment Booster Plus to increase chemical effectiveness.
A long-term approach to duckweed management involves stronger herbicides such as WipeOut or Sonar A. S. by SePRO. These products contain fluridone, which can control aquatic weed populations over the course of an entire season when applied in the spring. Because sunlight can reduce fluridone’s effectiveness, it is recommended to use Pond Dye alongside WipeOut or Sonar.
Once you have gotten rid of your lake or pond’s duckweed population, the next step is prevention. Duckweed thrives in calm, stagnant water. Focusing on water quality and aeration is your best bet for keeping future duckweed outbreaks at bay.
Use an all-in-one pond care solution such as ClearPAC Plus to keep your water free from muck and debris all season long. And installing an Airmax Aeration system will help create enough water movement to discourage duckweed growth.
If you are still struggling with how to get rid of duckweed in pond water, contact the experts at The Pond Guy for additional help.