This week the weather has not been temperate and we want to talk about pond weed control. No, we’re not crazy — now is the time! … time to start thinking about aquatic vegetation or pond weeds. While pond weed control is not an absolute necessity for a healthy pond, most pond owners want to control vegetation in their pond for increased aesthetic and recreational opportunities. It is not uncommon to overlook the pond and its abundance of vegetation until the days before your Fourth of July picnic with family and friends or maybe that much anticipated graduation party in the early days of June. If you wait until the middle of summer to gear up for pond weed control, you have missed your best opportunity and could potentially set the pond up for a fish kill.
Some of the most common “problem” pond weeds are filamentous algae and submerged weeds. Control of algae and other pond weeds can begin in very early spring when the water temperatures in the shallow margins of the pond reaches 60 degrees F. The benefits of getting a jump on pond weed control are numerous. Typically the weed population is easier kept in check over the later summer months with less frequent (and less costly) and more targeted applications. If weed control is delayed until mid-summer when the weeds are in full growth, the large mass of dying weeds will tie up much of the oxygen as they decay. Pond water is considerably warmer and the available dissolved oxygen for the fish can drop to lethal levels. Where fishing is a priority, the potential of a fish kill due to oxygen depletion from decaying plants after a mass treatment of weeds is high. An earlier start will greatly reduce the volume of decaying plants and minimize oxygen depletion. Any submerged weed control from mid-June or later should be limited in scope to reduce the potential of fish kill.
Prior to use of any aquatic herbicide, always identify the plants you wish to control and READ THE LABEL to be sure the herbicide you are choosing is effective on the plants you wish to control. Be absolutely certain you are storing, handling and applying the product according to the label. There are two excellent sources of pond management information available to Ohio pond owners. The Ohio Department of Natural Resources Division of Wildlife’s Ohio Pond Management Handbook (http://wildlife.ohiodnr.gov/species-and-habitats/pond-management) and The Ohio State University Extension Natural Resources Fact Sheets (http://ohioline.osu.edu/lines/ennr.html#EFACT) are available on their respective websites for review and download. Now, sit down by the window overlooking your pond with a nice hot cup of coffee or tea and plot your strategy to get out ahead of those pesky weeds and make this summer the best it can be in and around your pond.
Brad Ross is a Communications Specialist for Delaware SWCD.