A strategic variety of plants in your backyard pond can ease the job of maintaining your pond by providing shade and taking up excess nutrients in the water, both of which help to inhibit the growth of nuisance algae. Keep in mind that plants can’t control every aspect of a pond’s ecosystem, so you’ll still have work to do, such as maintaining a good mechanical and biological filter and ensuring good water circulation. In fact, a certain amount of algae on surfaces is necessary for your pond’s overall health, so the key is to limit its growth and to drive out any toxic algaes. In short, a good selection of healthy plants will always improve your pond’s water quality and appearance.
Pond plants provide three key benefits to your ecosystem: They oxygenate your water, which helps your fish stay healthy and also impedes the growth of anaerobic bacteria, which can produce toxins and an unpleasant sewer-like smell. The best oxygenators are typically submerged plants, which also provide easy spaces for your tinier fish to hide. Some excellent choices are eelgrass, hornwort, water thyme and elodea or anacharis. Plants also take up the nutrients in the water that algae require. Plants will always out-compete algae in the nutrient race, provided the environment is basically healthy. For fastest uptake, choose fast growing species like duckweed and water lettuce, but beware -- these can quickly become invasive and should be closely managed or removed once your pond is starting to clear. Marginal and bog plants are excellent candidates for long term control. They take up the bulk of their nutrients through their roots, so it’s a good practice to circulate water along the shelves where these plants rest -- choose options like watercress, pickerel rush and Taro. Shade is the third benefit to your pond, and is provided primarily by floating or floating-leaves species. Sunlight is critical to algae growth and a pond located where it receives plentiful direct sunlight is an algae explosion waiting to happen. Plants like water lilies, spatterdock, water hyacinth, and variegated water celery are all beautiful shade-providing plants. Plan to cover about 60% of your pond’s surface area, but no more since some sunlight is necessary to support the submerged, oxygenating plants.
