An invasive aquatic plant has been found for the first time in Michigan. Hydrilla is native to parts of Asia, Africa, and Australia but was recently found in two private ponds in Berrien Springs, Michigan.
The weed is not picky about where it grows and can tolerate a wide range of conditions. This, in addition to the fact that it can grow extremely quickly, has experts worried.
Jo Latimore is an aquatic ecologist at Michigan State University who is not surprised about hydrilla's detection in Michigan.
"We've been keeping our eyes out for it for years, because this is a plant that we really don't want to have here," she said.
Sometimes called "Godzilla hydrilla" by ecologists, the invader can grow up to an inch per day. It can form dense mats that choke out other native species of plants, degrade habitat for fish and other aquatic organisms, and create navigation difficulties for recreational boaters.
Bill Keiper is an aquatic biologist with the Michigan Department of Environment, Great Lakes, and Energy (EGLE). He said hydrilla has earned its other title of "one of the world's most aggressive aquatic plants" for many reasons.
"It's a really aggressive plant. It's difficult to treat, in that it persists for a long time, there aren't a lot of herbicides that work well on it, and it produces these tubers that can be in the sediment for several years before they pop back up. It has the ability to spread really quickly, and it's fairly cryptic, so a lot of times it doesn't get reported," Keiper said.
Hydrilla spreads in at least four ways: from small fragments that can get caught in boat propellers or fishing equipment, via seeds from flowers, from potato-like tubers under the sediment, and from buds that overwinter, called turions. This variety of dispersal methods makes hydrilla particularly difficult to control.
Like many invasive species, hydrilla is thought to have been accidentally introduced to waterways as a hitchhiker on ornamental plants.
Latimore said that, once established, the plant can be spread between water bodies as a hitchhiker on boats and fishing equipment, and that cleaning equipment could help stop the spread of the plant.
"For folks that like to boat and fish, or this time of year, go waterfowl hunting...just remember, it's more important than ever to clean, drain, and dry [your equipment] like we're always asking folks to do," she said.
She added that if you suspect you've found hydrilla: keep or photograph the specimen and reach out to EGLE or the Michigan State University Extension for confirmation.
