Plants play a vital role in the health and beauty of any lake or pond. However, excess aquatic vegetation may cause problems by impeding water flow, preventing recreational use, and reducing the value of the landscape around the water body.
Identifying the type of aquatic vegetation management in your pond is the first step in managing the problem. This guide can help pond owners distinguish between invasive plants and native look-alikes.
1. Identifying Problem Plants
Whether it is a small pond or a large lake, the health and beauty of any aquatic environment largely depend on the types of plants that grow there. Unfortunately, many of these plants can be considered invasive and negatively impact water quality and recreational activities.
Invasive plant species can form dense mats that choke out native vegetation, block sunlight, prevent sunlight-requiring plants from growing, and destroy fishing habitats. They also threaten boats and swimmers by tangling in motors, rudders, anchors, and hooks.
There are three main categories of aquatic plants: algae, floating, and submerged. This article focuses on undesirable or nuisance floating plants (not including algae which are discussed individually on our Algae Solutions page). These plants grow at the surface of your pond and can cover the entire surface creating an unattractive pond or blocking out sunlight that would otherwise reach other plants below. Some examples include duckweed and watermeal.
2. Identifying Algae
Algae are simple plants that live in oceans, lakes, rivers, ponds, and moist soils. They produce oxygen by photosynthesis and help clean the water. They are not a problem in and of themselves; however, when they form thick blooms, they can cause undesirable taste and odor, reduce water clarity and create unsightly scums. They can also produce toxins that can affect human health.
Thick accumulations of algae are often associated with excess nutrients (primarily nitrogen and phosphorus) in the water. These nutrients come from fertilizers, pet waste, septic systems, and grass clippings. Some algae multiply rapidly in response to these excessive nutrients and may produce toxins.
These toxins, called cyanotoxins, can lead to skin and eye irritation, gastrointestinal problems, liver damage, and even death in humans. Knowing the type of algae in your pond is important because some are very harmful and difficult to control with chemical treatments. Use the information on these individual plant pages to determine your species and find treatment options.
3. Identifying Emergent Plants
The addition of emergent plants can enhance a pond’s health and beauty. From cattail spikes to reeds and bulrushes that rattle in the wind to beautiful water lilies that float on the surface, emergent plants offer habitat, food, refuge, cover, and shade to fish and wildlife and provide aesthetic beauty.
Often considered to be weeds, these plants have roots mostly under the water, while their leaves and flowers grow above. They grow in shallow areas and along the shoreline of lakes, ponds, and rivers. They are also referred to as shoreline or wetland plants.
A natural balance of rooted aquatic vegetation is desirable in most ponds, but excessive vegetative growth can hinder the quality of a lake or pond. Invasive emergent plants can interfere with fishing and boating, impede wildlife habitat and contribute to unwanted foul odors. Uncontrolled invasive vegetation can also disrupt ecosystem dynamics and lead to economic damage. The key to avoiding this is through careful identification and management.
4. Identifying Submerged Plants
Submerged plants have their roots in the bottom of the aquatic environment, with most of their vegetative mass underwater (much like the sedges that make up much of your pond’s vegetation). One distinguishing feature is that their stems are flaccid or soft.
Some submerged plant species, such as muskgrass, commonly found in Pennsylvania’s lakes, are beneficial. It helps reduce phosphorus and serves as food for aquatic organisms. Unfortunately, invasive submerged plants such as hydrilla can quickly fill a lake’s surface.
Final Words
Overgrowth of these plants limits sunlight penetration and smothers native plants. This can result in deteriorating water quality conditions and losing important habitats.
Another benefit of submerged aquatic vegetation (SAV) is its role in absorbing atmospheric carbon dioxide. More
