Martin Dies, Jr.

Martin Dies, Jr. State Park All About: Invasive Exotic and Native Aquatic Plants Plants not native to an area, either brought in by accident or for a purpose, are called exotic. Those plants that occur in an area naturally are called native. Plants that grow quickly and take over an area are called invasive. Invasive plants can be either exotic or native. Depending on the location, native invasive plants can be very beneficial to wildlife, such as black willows colonizing a newlyformed sandbar. In man-made reservoirs where recreation is the primary focus, native invasive plants are often removed to provide access to fishing spots or paddling trails. Exotic invasive plants need to be controlled since they do not belong in that environment. Often times they do not have natural predators or pests to keep them from taking over, and often have little value to wildlife. When they overpopulate an area they can cover entire reservoirs, impact water flow, block sunlight, and starve the water of oxygen. They also prevent recreational activities such as fishing and paddling. Many plants have adapted to live in a variety of ponds, reservoirs, and streams. These plants can tolerate a diversity of water conditions ranging from swift-flowing to stagnant, fresh water to brackish water. Water Hyacinth - A somewhat tall (1 to 3 feet), free-floating plant with thick, glossy, ovate leaves, and feathery freehanging roots. It has violet spikes of flowers. Native to South America. American Lotus - Rooted plant with circular leaves up to 2 feet across. Large yellowwhite flowers, with a seed pod that resembles a showerhead. Native to North America. Hydrilla - Dark-green submerged plant with long branching stems and whorled leaves. Native to Asia, Africa, and Australia. Alligator Weed - An emergent plant with upright stems and 4 inch long opposite oval leaves. White flowers on short stalks. Can thrive in both dry and aquatic areas. Native to South America. Salvinia (common and giant) - Both species are small floating plants with oval-shaped leaves covered with tiny hairs on the upper surface. Giant Salvinia leaves are quarter to half-dollar sized, twice as large as common Salvinia leaves. Native to southern Brazil.