Ten Rules of Engagement for Battling Aquatic Weeds
By Kelly Duffie – Houston, TX
A pond-owner’s relationship with aquatic vegetation can easily reflect his relationship with kids. With kids, he can usually tolerate a few of the two-legged critters within his domain; and may actually enjoy their presence, so long as they’re well behaved. However, when an unruly brat arrives on scene, or when the house becomes over-crowded with scurrying munchkins, his attitude toward the situation may abruptly change.
So it is with aquatic vegetation. Certain types and amounts of aquatic vegetation cause minimal headaches and may actually enhance a pond-owner’s enjoyment of his domain. However, when a particularly nasty plant species invades a pond, or when low-density “vegetation” mutates into high-density “weeds”, the increasingly irritable pond-owner will often employ every available option as a remedy for the problem; sometimes posing a detriment to the pond’s unique ecosystem.
One of the greatest challenges that pond-owners face is the task of managing aquatic vegetation to an acceptable level without negatively impacting the pond’s overall aesthetic, utilitarian or recreational value.
Detailed books on the entire gamut of aquatic vegetation management methods and tactics would easily occupy several inches of bookshelf. Accordingly, it is difficult to offer a generic yet comprehensive aquatic vegetation management program due to the matrix of variables that exist from pond-to-pond and season-to-season. Therefore, this article will stick to the author’s concept of the ten basic “rules of engagement” for aquatic vegetation management.
- Rule #1: A pond’s design and initial construction should always limit the amount of shallow perimeter areas to that which will adequately support specific requirements. Excessive areas of shallow water will simply increase the primary habitat in which weeds and algae will establish their foothold for eventual invasion of the pond.
- Rule #2: “Clear water” is a weed-problem waiting to happen. Weeds and algae need water, nutrients and sunlight to flourish. In most cases, water-clarity represents the easiest – if not the only component that is subject to manipulation. Consider the options for decreasing sunlight penetration, such as a pond fertilization program or the use of lake-dyes. Pond fertilization, if properly administered, is preferred in recreational fishing ponds because of its benefit toward fish carrying-capacity. For much the same reason, the use of lake-dyes is normally discouraged in fishing ponds unless the natural food chain is supplemented in a significant manner.
- Rule #3: Pro-actively monitor and frequently inspect the pond to detect real or potential weed problems as early as possible. The ability to identify problematic species upon sight is critical. Many aquatic plant and algae species have phenomenal reproductive capabilities, so the ability to identify aggressive plant species, and initiate the early-season management tactics, is crucial to success. As an aneqdote, always remember that many of the worst forest fires were potentially manageable with a bucket of water had they been detected in their initial stage of existence.
- Rule #4: Evaluate and utilize the various weed management “tools” in a cautious manner. Ensure that the selected management option is actually effective on the targeted weed species. As with power tools, all weed management tools (i.e. mechanical harvesters, manual removal, herbivorous fish, herbicides or algaecides) pose certain degrees of risk, particularly when they’re improperly deployed.
- Rule #5: NEVER use an herbicide or algaecide in aquatic sites that are not labeled for aquatic sites. Too many times pond owners hear their neighbor mention that a non-labeled product works great on algae or weed control – and it’s cheap. Little do they realize the long-term impact that these cheap remedies pose on other organisms in the pond – including the fish. Chemical manufacturers are not likely to overlook a safe and profitable market for their products. Therefore, if a pesticide isn’t labeled for aquatic-use, rest assured that there is a very good reason why the manufacturer did not pursue such uses on the product’s EPA registration.
- Rule #6: When using pesticides, be sure to understand how the product should be applied. Using the correct product incorrectly will most likely produce poor results. The leading cause of so-called “product failures” is improper or inadequate application technique and/or equipment.
- Rule #7: When using aquatic herbicides and algaecides, insure they are applied during favorable seasonal and weather conditions. Some products achieve optimum effectiveness with a springtime treatment while others perform better during the warmer temperatures of early summer. Several products are ideally applied only under sunny conditions. Other products should only be applied when rain is not expected for several hours, or when water levels are static for several days or weeks.
- Rule #8: When using aquatic herbicides and algaecides, avoid the common misperception that “If a little bit is good, a lot is better!” You can only kill something so dead. A product’s labeled use-rate should effectively perform the job if the treatment is properly conducted. Over-dosing treatments may create serious consequences for fish and other non-targeted organisms and negatively impact the pocketbook without improving the final results
- Rule #9: Don’t waste time looking for a one-shot “cure-all” or “permanent” treatment for aquatic weed problems. Besides draining a pond of all water, it is unlikely that nuisance aquatic weeds will disappear forever.
- Rule #10: If a pond-owner is unwilling or unable to study and implement a proper aquatic vegetation management program, he may be better off to hire a reputable lake management company to tackle the challenge. Aquatic vegetation management is as much an art as it is a science, so contracting the services of an experienced lake management provider may help avoid many serious weed problems down the road.
Understanding these 10 basic rules of engagement is the first step toward a successful aquatic vegetation management program. Beyond these simple guidelines, every pond should receive a vegetation management program designed for its specific needs, uses and circumstances.
Obviously, managing aquatic vegetation is not a small or simple task. But the reward of a navigable, “fishable”, and aesthetically pleasing pond is invaluable, and is well worth the effort.