The health and wellbeing – not to mention aesthetic – of any waterbody largely relies on its aquatic plants. What exactly is an aquatic plant? An aquatic plant is any type of vegetation that grows in water, including saltwater in oceans or fresh water in creeks, rivers, ponds, and lakes. These aquatic vegetations have unique characteristics that enable them to thrive in their environments while helping to create a balanced ecosystem; but, overgrowth of these plants or the presence of invasive species can wreak havoc on lakes or ponds.
What’s the Difference Between a Native Aquatic Plant and an Invasive Aquatic Plant?
Before diving into the types of aquatic plants, it is important to make a distinction between aquatic plants versus invasive aquatic weeds or plant species.
Invasive aquatic plants have the following characteristics:
- Sometimes brought to waterbodies for aesthetic purposes
- Often spread via the movement of boats and recreational equipment
- Presence and overgrowth can cause environmental harm, Harmful Algae Blooms (HABs) and impact recreational use
Native aquatic plants have the following:
- Usually naturally found in the waterbody or transferred with no detrimental effects
- Can still have negative impacts if not properly managed
It is important for any waterbody management plan to take both types of species into consideration.
What Are The 4 Types of Aquatic Plants?
As the chart below shows, there are four main categories of aquatic plants:
- Rooted Floating
From here, we’ll go through each type of plant, what to watch out for, and a few examples.
Submerged Lake and Pond Plants
As the name implies, submerged aquatic plant species grow underwater with roots in the bottom of the waterbody, and most of their vegetative mass is under the water’s surface. This type is known be especially effective at oxygenating – taking carbon dioxide from the water and releasing oxygen.
One such plant, Muskgrass, is perfect for ponds with excess nutrients as it consumes a large amount of these – all while acting as a food and hiding resource for aquatic life. It can be identified by its thin, straw-like stem that will turn flaccid one broken (opposed to snapping or bending).
An invasive submerged species is one you may have heard of, Hydrilla. With long, branching stems and teeth-like leaves, hydrilla can break apart and form large floating mats. This species can also grow in deep or shallow water, helping it to spread quickly.
Free-Floating Lake and Pond Plants
Free-floating aquatic plants have no roots within the bottom of the waterbody, although their roots do reach into the water to absorb nutrients and act as filters. Since they are unattached, they can withstand movement from wind, waves, and boats. As such, these tend to be very small and typically are found in nutrient-rich waters.
An example of a common free-floating plant is Duckweed. Duckweed consists of many single, flat oval leaves (about ¼ of an inch long) which float on the waterbody’s surface. While this aquatic plant serves as a food source for waterfowl and aquatic life, it can be a nuisance for human recreational use, and overgrowth may result in oxygen depletion and fish kills.
Water Hyacinth, a free-floating plant, is also one of the most infamous invasive aquatic plants – particularly in Floridian waters. This is due to its fast-growing capabilities that allow it to cover waterbodies quickly and effectively and waterways, impeding travel and recreational use. They can be identified by their prominent purple flower with a yellow spot.
Rooted-Floating Lake and Pond Plants
Rooted-floating aquatic plants are rooted in the waterbody’s sediment, and typically have leaves that float on the water’s surface. Since they are attached to the ground and still reach the surface for many of their nutrients, rooted-floating plants tend to be found in shallower waters with little to no water movement.
Waterlilies are an example of Rooted-Floating plants that most people are familiar with thanks to their vibrant green pads and white or yellow flowers. But, as pretty as they may be, waterlilies should be grown in moderation to keep them from overgrowing and covering the surface of the pond – thereby eliminating oxygenation.
Emergent Lake and Pond Plants
Emergent aquatic plant species explicitly grow deep roots within the waterbody’s sediment while the bulk of their mass – leaves and flowers of the plants – grow above or spread out over the water’s surface. This allows them to offer not only aesthetics but shade and hiding places for fish and other aquatic life.
Cattails, which grow 5 to 10 feet in height with a dense, dark brown, cigar-like shape on their top, are an emergent plant that can assist in keeping lakes and ponds healthy. Cattails filter runoff into waterbodies, provide nesting environments for nearby wildlife and also serve as a food source. Still, these emergent plants spread quickly and can turn a pond or lakeshore into a marsh.
Water Primrose, an invasive emergent plant in ponds and ditches, is sword-shaped, about 6 inches long, covered in small soft hairs, and topped by yellow flowers. While this plant can provide food and shelter for aquatic life and fish.
Looking for Management of your Waterbody’s Aquatic Plants?
Our experts at Clarke have years of experience working with a vast variety of lakes, ponds, stormwater ponds and more, with a focus on catering to their unique needs and goals and an emphasis on using science-based techniques and technologies to do so. To learn more, contact our team here, or check out our Aquatic Plant Management services, Our Guide to Virginia Plants or other articles such as