It would be hard to exaggerate the negative impact invasive plants make on Connecticut.
They are the more than 100 plants not native to Connecticut and they cause environmental, economic and human health damage, and choke out native species, according to experts. But the state is fighting back, and the Connecticut Department of Transportation is among those fighting.
The DOT is using Foamstream and AquaPro in its arsenal for killing invasive weeds in environmentally sensitive areas, and the goal is that someday technology will improve these products and they can replace the need for herbicides use by the CTDOT.
The environmentally friendly products from the two different manufacturers have “worked well” since being first used by the CTDOT in 2024, according to Chris Samorajczyk, the supervising environmental planner for the Central Maintenance Administration for the agency.
Foamstream is one of the environmentally safe options being used to kill invasive growth in the state.
The DOT has been using Foamstream and AquaPro in specific areas such as paved islands and barrier systems in vicinity to watersheds. The technology is not being used for any big projects with the bureau of highway operations or maintenance.
An example of manual invasive plant removal day and planting at Hamden Town Center Park in June 2023. (Courtesy of Save the Sound)
Both products use high temperature steam to burn the upper and lower parts of the plants. Foamstream’s non-herbicidal foam is made up of coconut oil, wheat, grapeseed oil and potatoes. The DOT said the foam functions as a kind of thermal blanket, heating weeds long enough to eradicate them.
“The AquaPro has the same kind of methodology, but it’s a hotter temperature. It burns at about 212 degrees Fahrenheit. It doesn’t have the foam, and it’s just kind of like, you’re washing weeds and killing them,” Samorajczyk said.
“Both of them definitely have their advantages. We found the Foamstream first, and we were just trying to get out of the pesticide-related business,” he added. “It’s really just smaller, herbaceous weeds. It’s not really for any of the larger stuff. Overall, the small program that we’re trying to start is working well and if it keeps continuing to be that official to the department, we’re looking at possibly getting other units and kind of just getting these units available for more garages and more areas.”
For now, there is only one of each unit in the state and it will begin to be deployed in communities in the coming weeks. Foamstream equipment can fit in the back of a pickup truck and the AquaPro can fit in a small trailer and focus on a specific area.
“Our workers would go out, probably the first week of May and spray them and hopefully kill them for the whole season,” Samorajczyk said.
“The public likes it because our workers aren’t on the road four times [in} that area for the year. They hit it once and that’s the real value in it for us. It hasn’t grown to being a long linear roadway project yet. It’s really smaller areas. We’re just seeing where we can use this and utilize it for the best of the department,” he said.
This technology is not capable at this time for use with the DOT’s guiderail program, which uses herbicide for guiderails, signs, and barriers within the state-owned right of way. The guiderail program needs the slow rolling process in which the DOT is moving at 15 mph to 20 mph on roads or highways, spraying invasive weeds with herbicide with a wand attached to the truck.
Foamstream and AquaPro can only be used at a stand still and the plants need to be soaked two times with the products.
“We talked with both manufacturers about our guiderail program and the need for wands on the front of the truck. Right now, the technology is not there. They are looking at technology that would produce wands for us to use to spray on the guiderails,” Samorajczyk said.
“Right now, we are using them for anywhere towns have brick islands in the road or anywhere weeds would pop up. We want to get to a point where we can spray it like a mobile convoy and get those guiderails,” he said.
Andy Morrill, the DOT’s maintenance manager of Special Services, Foamstream and AquaPro are not a replacement for the herbicide product the DOT uses.
“We brought those two pieces of equipment in to try alternatives to get to an end goal of either reducing or completely eliminating the use of herbicide. Unfortunately, the industry and the technology is not there yet,” Morrill said. “But we’re trying alternatives. We are trying a bunch of different items that are environmentally friendly to get to that point.”
Morrill said he has no timeline on when that type of technology will be available for the DOT, with the hopes of someday completely phasing out herbicide.
“That’s a question I can’t really answer, because it’s based on the manufacturer and technology and their adaptation to how quickly they can get their product, a viable working product, onto a mobile piece of equipment that makes sense for us to use. We’re trying to keep our personnel off the road as much as possible, and do everything from vehicles, as much as possible, because those are a safer mechanism. Until they come up with a better viable product, we are going to continue to research and find what’s out there,” Morrill said.
John Woike / Hartford Courant
Examples of center aisles at the intersection of RT9 and Exit 16 to the Arrigoni Bridge.
Samorajczyk said for what Foamstream and AquaPro do, they have “a high percentage of mortality” for invasive smaller species.
“It works almost instantaneously. The larger and the thicker bases of these herbaceous plants, the longer it might take,” Samorajczyk said.
“The technology is hitting the above ground portion. It’s going down and it’s really cooking the roots. It definitely doesn’t work on woody stem. We’ve tried it on some species like Japanese knotweed and it’s not really effective. If you hold the wand over the plant a little longer, maybe 30 seconds, we saw some mortality,” he said. “But you really need to do a slow sweep, of 5-10 seconds over the area that you’re trying to address, and that’s really why it doesn’t work for a vehicle right now.”
“It’s a really slow process. It’s kind of new technology and we’re hoping that if it ever catches up to being able to be used in a mobile unit, that will really add value to us in our programs,” he said. “We definitely want to look at this type of technology to see what would be beneficial for us on a larger scale. That’s where we’re at now.”
Samorajczyk said the DOT mixes in cutting back invasives and also treats with herbicide, depending on the site.
“We’ll use minimal herbicides and we’ll actually use herbicides that are probably less than the label recommends. We’re always compliant with staying federal regulations and are even lower than a private homeowner could use. Our guys and our vendors are all licensed and they’re calibrating the machines that we use for the guide row spray at a lower dosage than even prescribed,” Samorajczyk said.
Samorajczyk said when the DOT is in its convoy using herbicide, the front truck is in communication with the back truck and as soon as they enter a regulated, or wetlands and watersheds areas, the machines are turned off. The DOT also sprays under the guard rail and not into the wind into adjacent forests.
“It bonds to the soil right away. It doesn’t leach through. All this stuff is through other DEEP (Department of Energy & Environmental Protection) permitting and allowable activities,” Samorajczyk said
Samorajczyk said Foamstream and AquaPro have not proved effective against hardier invasives like mugwort or thicker invasives like goldenrod.
“We really are hoping that we work on that kind of stuff. We haven’t found that it works on that now or with much success. I don’t know if the technology ramps up a little and we may be at another level of stuff that would be beneficial to us. But right now, we’re just using it for basically just keeping the big kind of center medians on our interstates free of weeds where we can. We also use it for cracks and pavements and parking lots and commuter lots,” Samorajczyk said.
Samorajczyk said that high temperatures are what kills weeds with Foamstream or AquaPro and also noted that the DOT is speaking with vendors and scientists who are developing this technology to have a wand on the front bumper to kill weeds on guiderails.
“They can’t find where the heat holds to kind of run it in the way we need it. They tell us they’re working on it, and if they ever got to that, that’d be fantastic. Because then we could just go 100% pesticide free,” Samorajczyk said.
“We’re looking for any viable alternative that is safe for both our employees and the environment. It’s not just limited to these two companies.,” Morrill added.
The Connecticut Department of Energy and Environmental Protection also is in the fight against these plants, such as with its aquatic invasive species grant program that has been providing funding to combat invasive aquatic plants like hydrilla for over five years. The highly invasive hydrilla chokes out all other native plant species in the water it infests.
Greg Bugbee looks for turions. a resistant plant bud found in certain aquatic plants and can allow the plant to survive winter in the vegetative state (i.e., without setting seeds). (Edmund H. Mahony)
The Connecticut Invasive Plant Council maintains an official state list of which plants have been categorized as invasive since 2004.