These days, my phone keeps ringing about ponds clogged with aquatic weeds and algae. If your pond’s surface is more than 20% covered with weeds or algae, you should work with a pond management company to tackle the issue. An additional step toward the prevention of this issue is tracking down the cause. Aquatic weed growth and algal blooms are usually caused by excess nutrients in the water. These nutrients come from many different sources, but common sources are sedimentation from shoreline erosion and the transport of excess nutrients from fertilizers through stormwater runoff.
One easy way to tackle nutrient management is through the use of vegetated buffers. These buffers use native plants to protect the pond’s shoreline and water quality. Native plants have large and deep root systems that help to stabilize soil to prevent erosion. While it’s common to see turf grass along the water’s edge, turf makes a poor shoreline plant. It has shallow roots and doesn’t tolerate wet soil conditions well.
Native plant buffers also protect water quality by serving as filters to runoff. When water runs off the surrounding landscape, a buffer intercepts contaminated stormwater runoff before it enters the pond. It slows the water down, giving pollutants like sediment time to drop out of suspension. The plants also take up pollutants like excess nutrients. This lets cleaner water enter the pond and can preserve water quality.
There are two ways to encourage a buffer: direct transplants or an alternating mowing regime. In both cases, a fertilizer/pesticide-free zone should be established around the pond. By directly transplanting native, wetland plants, you can design a shoreline for function as well as aesthetics. This will require some upfront costs, though. Instead of purchasing plants, you can encourage native plant growth with a low-mow meadow. Reduce mowing around the pond to every other year (alternating spring and fall) to limit the growth of annuals and woody vegetation. However, low-mow meadows take longer to establish desirable plants and provide benefits.