Some common plants found in residential ponds in the Southeast can multiply very aggressively and alter your pond’s or lake’s chemical composition, threatening indigenous aquatic plants and fish populations. And, they can make your pond or lake less enjoyable. So, it’s important to take control of invasive plant problems as quickly as possible. Here is some helpful information about eight plants that South Carolina pond owners are advised to learn to identify, followed by a list of recommended ways to control or eliminate these plants from your home’s pond or lake.
1. Egeria (Brazilian elodea)
The Egeria weed is a perennial. The slender branching stems grow up to 6 feet high. The leaves have linear, finely serrated margins. The small 3-petal flowers bloom above the water. Egeria grows year-round, but it is very competitive during summer in lakes, ponds, rivers and streams.
2. Cabomba [Cabomba caroliniana]
Cabomba is an annual plant with green or reddish leaves that are dissected, opposing and fan-shaped, soft and flexible. Its small flowers blossom above the water level, and are three-leafed, white, cream, pink or yellow, and sometimes spotted.
3. Hydrilla (Hydrilla verticillata)
Hydrilla is among the most common invasive aquatic plants in the US mid-Atlantic region. Its slender, branching stems grow submerged up to 20 feet long. Its leaves are small and pointed, with a spiny ridge on back. The tiny flowers are translucent to white. Hydrilla forms thick mats, which may float up and cover water surface areas. Hydrilla looks similar to Egeria, but is smaller and rougher in texture.
4. Chara (muskgrass)
Chara may look like a plant that will flower, but it is really a multi-cellular macro-alga. It grows clinging to the bottoms of lakes, ponds, rivers, and even ditches. It forms beds of vegetation that can grow from several inches to several feet in height. It has no leaves, just 6-8 branches growing along the stem. Chara is also recognizable by its strong garlic-like odor.
5. Lyngbya (Blue-Green Algae)[Lyngbya agardh)
Lyngbya grows into thick floating or submerged mats of cells covered with its own external sheathing. In warm months the mats may completely cover a body of water. During the spring, Lyngbya is black, and it gradually forms hair-like filaments through the summer and fall that are green, black and white. Lyngbya can flourish in extreme temperatures, from icy water to hot springs.
6. Coontail (Ceratophyllum demersum)
Coontail is a free-floating, rootless, submerged plant that thrives in stagnant ponds, lakes, and rivers. Its stems can grow up to 15 feet in height. Its small, feathery, fan-shaped leaves grow in whorls around the stem (giving it an appearance resembling a raccoon tail). The leaves have tiny teeth-like edges that give the plant a rough feel. Its tiny flowers grow in its leaf axils.
7. Eurasian watermilfoil (Myriophyllum spicatum)
Eurasian water milfoil has slender stems and feathery, thread-like submersed leaves. Its small, 4-petal flowers grow in the axils of the plant above the water. Coontail looks similar to milfoils, but without individual leaves.
8. Brittle Naiad (Najas minor)
Brittle Naiad grows submersed. It’s an annual weed with numerous branched stems up to 4 feet long. Its small, linear, toothed leaves become brittle with age. The plant has a bushy appearance, with barely noticeable flowers in the leaf axils.
Strategies for Controlling Invasive Species
Invasive plant species may grow submerged, or live on the surface of your pond. Each species comes with its own potential impacts on your pond’s ecosystem health. So, each type requires specific strategies for remediation. Commonly recommended approaches to controlling invasive plant species include:
Mechanical – Rakes, harvesters, seines, hoes, grappling rigs, and other tools can be used to quickly clear out invasive plant growth. If you use your pond or lake for recreational boating or swimming, this is an efficient method for restoring its pristine natural beauty.
Biological – Lakes and ponds are ecosystems. They must function healthily as such. Introducing natural predators can be effective in eliminating invasive plants that are crowding out other vegetation. Disposing of unwelcome plants properly is fundamental for controlling their numbers.
- Include recommended species of fish and insects.
- Check your plant purchases for unwanted plant fragments, seeds, fish, or snails.
- Don’t dispose of unwanted plants or animals by releasing them in other water bodies.
- Don’t throw plant debris in your composter. Seeds can transfer elsewhere. Dry the plants completely and then dispose of them in a trash can.
- Follow regulations governing sale, possession and transport of invasive plants. If you are unclear on what is allowed, use only native plants.
- Avoid putting your pond very close to natural ponds or lakes that may contain invasive plants which may be too easily transferred to your area.
Physical – Altering your pond’s or lake’s physical properties can help promote healthier water chemistry and limit damage that can be caused by invasive species. There are several simple, long-term solutions to a range of water quality problems that contribute to growth of algae and various other invasive species. Consider adding one of the following features to your pond or lake.
Herbicides and Algaecides – Applying commercial products to control the proliferation of unwanted plant life in your pond or lake can be a very efficient method.
- When this approach becomes necessary, it is of paramount importance to have the process performed by a qualified professional.
- A trained professional can assess your specific needs for applications and ensure minimal negative impact on other plants and animals.
Invasive plants can be carried from other waters or by discarded plants from aquariums, by winds or birds transporting their seeds to nearby public waters. They may then begin to rapidly over-take lakes, creeks, or rivers. This encroachment often leaves indigenous plants and animals to perish in un-survivable water conditions.
You may need to combine some of the above methods for managing your pond to prevent encouragement of invasive plants. For instance, biological or mechanical means may be effective interventions for clearing out some nuisance plants. In other cases, careful application of appropriate amounts of herbicides that are professionally recommended for your specific needs can be used to eliminate invasive plant species.
For More Information
For more information about how to overcome encroachment by invasive plants in your pond or lake, or for irrigation issues, contact Irrigation Outlet any time for help from our expert team.