Key ID characteristics for Hydrilla verticillata
Early detection gives land managers the best chance to stop invasive species spread. Help our region by learning the key features that confirm hydrilla’s identity!
1) grows in whorls of 3 or more
2) has noticeably toothed leaf edges
3) is the only submerged plant to produce tubers
Leaves and stems
- Leaves grow in whorls of 3-8 and have noticeably toothed edges
- Leaves are generally 2-4 mm wide, 6-20 mm long
- Midrib, on the underside of leaf, may be reddish and has spines that make it rough to the touch
- Stems may be up to 30 feet long
- Tubers are small, potato-like structures, and consist of white or yellowish overlapping scales formed at the end of roots.
- Hydrilla is the only submerged plant that make tubers in our region
- Tubers may remain dormant for several years in sediment regardless of ice cover, drying, or herbicides.
- A single tuber can grow to produce more than 6,000 new tubers per m2 (Sutton et al. 1992).
Hydrilla tubers are about the size of a pinto bean and can lead to new infestation.
- There is only one species of Hydrilla in the world.
- Hydrilla verticillata’s dioecious type (plants having female flowers only) originates from southern India. Hydrilla’s monoecious type (plants having male and female flowers on the same plant) is probably from
Korea. (Madeira et al. 1997).
- Occurs in Europe, Asia, Australia and the Pacific, Africa, South America and North America.
Just remember that Hydrilla grows in whorls of 3 or more, has noticeably toothed edges, and is the only plant to produce tubers
Report new sightings. If you think you have found an invasive species, note its exact location and, if possible, take a photo. Report new sightings to Mark Warman at Cleveland Metroparks. firstname.lastname@example.org, 216-346-2234.