By: Tonya Barnett, (Author of FRESHCUTKY)
Natural or man-made ponds in the garden landscape can serve a variety of purposes. While some may choose to create a fish pond, other homeowners may focus more on the aesthetic aspect of this water feature. Regardless, the presence of plant life is an integral part of a healthy pond ecosystem. Aquatic plants, such as the water lily, serve many purposes too. However, controlling water lilies (and other plants) is especially important when plant cover becomes too thick.
Though beautiful, water lily management is necessary when plants begin to invade the vast majority of the pond. Too many plants growing in the water may be a major cause for concern, such as the reduction of available oxygen (which the plants absorb at night) and negative impact on the overall health of fish. However, water lily management may be somewhat challenging.
As one would imagine, the underwater nature of these plants makes water lily control quite interesting. In most cases, the easiest way in which to manage water lily weed is through prevention. Newly introduced waterlily plantings should always be made in the form of potted plantings, as this will help to reduce the likelihood that the plant will be able to spread through underground rhizomes.
In already established plantings, there are some other options for controlling water lilies. Removing the roots and rhizomes of the plant is possible, however, difficult. In most cases, this process will require tools specifically designed for the removal of aquatic weeds. Care also must betaken, as incomplete removal may cause the spread of the rhizomes.
Many growers choose to implement the use of weed barrier within the pond. Simply, pond weed barrier is placed at the bottom of the body of water after all water lily stalks and foliage have been removed. This barrier does not allow sunlight to reach the rhizomes, thus ensuring that they do not return.
Chemical herbicides are also an option for the elimination of water lilies from ponds. However, if choosing to implement these practices, it is imperative to only use products that have been specifically identified for use in ponds. Before use, always read all precaution and instruction labels in order to ensure its safe use.
This article was last updated on
Read more about Water Lily
Once you have confirmed that you are dealing with Water Lily, proceed with inspection. During this phase, you will locate the areas where Water Lily is thriving so you know where to focus your aquatic herbicide application.
Where to Inspect
Walk around your lake or pond to observe the Water Lily and to see just how big of an infestation there is. This is important for the purpose of knowing how much herbicide you need to treat the weed. Survey your lake or pond and determine what the best and safest plan of option there is to take. You wouldn’t want to harm any beneficial desired vegetation, fishes and other aquatic creatures.
This would also be a good time to test the pH of the water. What you’re hoping for is a pH level below 8. Water with an 8 or higher pH level hurts the effectiveness of aquatic herbicides.
What to Look For
Water lily is a hard plant to miss. By observing your water body, you will be able to detect it pretty easily with it's floating wide leaves that are split to the stem at the center and may have white or pink flowers growing on it.
We appreciate the helpful editorial advice of P.Hipkins, L. Hipkins, and B. Brinlee.
Disclaimer: Commercial products are named in this publication for informational purposes only. Virginia Cooperative Extension does not endorse these products and does not intend discrimination against other products which also may be suitable.
Reviewed by Michelle Davis, Research Associate, Fisheries and Wildlife
Virginia Cooperative Extension materials are available for public use, reprint, or citation without further permission, provided the use includes credit to the author and to Virginia Cooperative Extension, Virginia Tech, and Virginia State University.