Invasive species are non-native plants and animals that cause harm to the environment, economy and even human health. The Adirondack region has an opportunity to prevent invasive species from widely spreading. We need your help to identify invasive species, report sightings and use best management practices to control their spread.
Who am I?
Hydrilla can grow more than an inch a day, reaching lengths of 25 feet and growing in water depths of 20 feet or more.
(Photo courtesy of Chris Evans, River to River CWMA, Bugwood.org)
I am hydrilla (Hydrilla verticillata Lythrum salicaria), also known as water thyme.
Why am I a problem?
I grow aggressively - an inch or more per day - and invade lakes, ponds, rivers and marshes. I crowd out native plants, degrade water quality and habitat for fish and other wildlife, and inhibit aquatic recreation. My thick mats can slow the movement of water, disrupting water supplies and impeding drainage and irrigation.
Where did I come from?
I am native to Southeast Asia and was brought to the United States through the aquarium trade. I was first found in the wild in Florida in the 1950s and have since spread to many parts of the U.S.
What do I look like?
I am a perennial aquatic plant that grows to lengths of 25 feet. I have long stems that branch at the water's surface and form dense mats. I usually have four to eight small, pointed leaves arranged in circular whorls along the length of my slender stems. The edges of my leaves are lined with sharp teeth, and each leaf may have a reddish midrib. I have white floating flowers and small, white to yellowish, potato-like tubers attached to my roots.
Where do I live?
I am extremely hardy and can grow in many conditions (including low light levels and poor nutrient areas) and a range of depths, from shallow areas of just a few inches of water to depths of 20 feet or more.
How do I spread?
I am still available for sale as an aquarium plant. Sometimes I am used as packing material to help keep ornamental water garden plants moist. Once released in the wild, I quickly spread since fragments can sprout roots and establish new populations. Fragments are easily caught and transported by boats and boat trailers and can be dispersed by wind and water currents. I also reproduce and spread by buds produced along stems (called turions) or overwintering tubers. I rarely flower and set seed.
How do you get rid of me?
Mechanical, cultural, herbicidal and biological management practices each cost anywhere from thousands to millions of dollars to implement each year.
Who looks like me?
I am easily confused with a beneficial native water weed, Elodea, whose leaves typically occur in whorls of three and appear smooth-edged.
What can citizens do?
Always clean, drain and dry watercraft and gear after leaving a boat launch to remove any "hitchhiking" vegetation. While boating, keep eyes open for suspicious aquatic plants or fragments. Send samples and report sightings to the Adirondack Park Invasive Plant Program. If you purchase plants for your water garden, always check shipments for unwanted stowaways. Never purchase hydrilla; always dispose of unwanted aquarium plants in the trash, never the wild.
For more information: Log onto www.adkinvasives.com or contact the Adirondack Park Invasive Plant Program at 518-576-2082.
Eye on Invasives is a seasonal, biweekly column that spotlights a top invader when it is easiest to identify. Hilary Smith directs the Adirondack Park Invasive Plant Program, a partnership program housed at the Adirondack Chapter of The Nature Conservancy in Keene Valley. Find out more about this award-winning program online at www.adkinvasives.com.