How to Identify Hydrilla

The Hydrilla verticillata, or water thyme, is an underwater plant that grows under any freshwater body of water including lakes, marshes and tidal zones. This invasive plant is found throughout many areas of the United States, causing problems such as slowing water flows, pushing out native plants and killing fish. Fortunately, the hydrilla has several distinct characteristics that enable you to identify it. Know how to spot this plant so you do not introduce it to your own aquarium or inadvertently dump it in a body of water.

• 1

  Inspect the stems of the water plant in question. Hydrilla plant parts are thin and long, often growing to 25 feet. Further, when hydrilla grow past the surface of water, these stems branch out across the top.

• 2

  Look for any saw-toothed leaves along the region of the stems. The leaves grow in a group between four to eight and are pointy and curly.

• 3

  Inspect the area where the leaf meets the stem (leaf axil) for turions (buds). These buds are cylindrically shaped, dark green and about a quarter-inch long.

• 4

  Search for flowers on the plant. Hydrilla contain small, white blossoms that bloom on top of long stalks.

• 5

  Look at the root tips to find tubers, which are subterranean turions. These plant parts look like small potatoes, display yellow shades and are a half-inch long and wide.

• 6

  Note the temperature of the environment where you find the hydrilla. This plant thrives in temperatures ranging from 68 to 81 degrees Fahrenheit, but can withstand higher temperatures, according to the Center for Aquatic and Invasive Plants.