Non-Native Species
What is Non-Native Aquatic Vegetation?
If you have resided at Smith Mountain Lake during the past several years, you may have heard the term “non-native aquatic vegetation”. This term simply means that the aquatic vegetation is not native to this area. In other words, it was most likely introduced by human interference. The terms “invasive” or “nuisance” are also used to describe a non-native species. Nuisance vegetation are just what their name implies – they may become a nuisance to a property owner. On the other hand, aggressive non-native aquatic vegetation is more serious. It tends to spread rapidly and often destroys native vegetation already in the location. A well-known invasive aquatic vegetation, Hydrilla, was identified in SML for the first time in 2007.
Since 2002, TLAC has contracted for aquatic vegetation surveys which identified both native and non-native aquatic vegetation present in SML. The most recent survey indicated that there are four types of non-native aquatic vegetation growing in the Lake. One, Brittle naiad, is a nuisance aquatic vegetation. Three others, Hydrilla, Brazilian elodea, and Curlyleaf pondweed are aggressive non-native aquatic vegetation.
More information can be found here:
Virginia Department of Wildlife Resources Aquatic Plant Id and Treatment
Non-Native Aquatic Vegetation in Smith Mountain Lake
Brazilian Elodea – Egeria Densa
Description: Brazilian elodea is an aggressive, non-native aquatic vegetation. It is a submerged perennial plant which is native to South America. This plant grows both rooted to the bottom and free floating in the water. It is suspected that it was originally introduced in North America through the aquarium trade. Elodea forms dense surface mats. It generally takes over the native plants. This plant grows in water as deep as 20 feet.
Stems: The stems are bright green. There are often numerous branches from each stem.
Leaves: The leaves are straplike and about 1 inch long. They usually have 4 whorls with 4-6 small leaves.
Flowers: Flowers are about ¾” across with 3 white spreading petals.
Reproduction: This plant reproduces by fragmentation.
Often Confused with: Hydrilla
Distribution: Brazilian elodea has been identified Smith Mountain Lake.
More information about Brazilian elodea:
Invasive Plant Atlas of the United States
Brittle Naiad – Najas Minor
Description: Brittle naiad is a nuisance, non-native aquatic vegetation. It is a submersed annual aquatic plant which was introduced into the United States from Europe. This plant grows in mixed stands with other non-native aquatic species or by itself, taking over the native plants. It can form dense shoals and surface mats in the water and is readily spread by boat traffic and water movements. Waterfowl often eat the seeds.
Stems: The branched stems of Brittle naiad grow to 4 feet or more in length.
Leaves: The leaves are opposite and linear and are usually 1 – 1 ½ inches long with 6 – 15 marginal teeth on each side of the leaf.
Reproduction: Reproduction is by fragmentation and seed production. The plants are brittle and easily break into fragments when disturbed. Each fragment can take root and produce another plant.
Flowers: Flowers are very small and inconspicuous and are produced separately in the leaf axils.
Distribution: Brittle naiad has been identified in many locations at Smith Mountain Lake.
View or Download the following pdf on Brittle Naiad:
NC State University Aquatic Weed Fact Sheet
Curlyleaf Pondweed – Potamogeton Orispus
Description: Curlyleaf pondweed is an aggressive, non-native aquatic vegetation. It is a submersed perennial plant which was introduced into the United States from Europe. This plant grows in mixed stands with other non-native aquatic plants, or by itself, taking over the native plants. It can form dense canopies on the water surface which may impede watercraft and limit swimming. This pondweed can grow in low light and low water temperatures. The stems of this plant tend to reach the water’s surface well before any of the other vegetative species. This plant grows in water as deep as 15 feet.
Stems: The stems are zigzagged, with alternate leaves and generally grow 1 – 3 feet in length. They become more dense toward the end of each branch.
Leaves: The leaves are somewhat stiff and approximately ½ inch wide and 2-3 inches long. The leaves are often reddish-green and have finely toothed margins.
Flowers: Flowers are small, somewhat inconspicuous and arranged in a dense spike.
Reproduction: This plant reproduces by turions (seed-like growths).
Often Confused with: Clasping-leaf Pondweed, a native aquatic plant
Distribution: Curlyleaf pondweed has been identified in Smith Mountain Lake.
More information about Curlyleaf pondweed:
Invasive Plant Atlas of the United States
Hydrilla – Hydrilla Verticillata
Description: Hydrilla is an aggressive, non-native aquatic vegetation. Hydrilla has been categorized as one of the world’s worst weeds, and it is certainly among the most notorious of submerged aquatic plant species. Infestations of Hydrilla are extremely severe and can completely choke entire lakes and public water supplies.
Leaves: Leaves are small and pointed, oppositely arranged, and generally grow in whorls of five. Leaves are sometimes serrated along the edges; midrib of leaf is often reddish and has one or more sharp spines.
Flowers: Flowers are tiny, white and grow on long stalks.
Reproduction: Distinct tubers are 1/4 to 1/2 inches long, off-white to yellowish, potato-like structures that attach to the roots. Hydrilla is mainly introduced to new waters as castaway fragments on recreational boats, their motors and trailers. The spread of Hydrilla from one body of water to another can be greatly reduced if boaters remove all aquatic weeds from boats, trailers and fishing gear before leaving lakes, rivers, ponds and streams. Fragments can get caught on the underside of boats and spread the weed from one location to another.
Often Confused with: Brazilian elodea
Distribution: Hydrilla had been identified in Smith Mountain Lake until 2013 when grass carp were introduced.
More information about Hydrilla:
Invasive Plant Atlas of the United States