When weeds run amok in lawns, gardens, or walkways, gardeners usually only have two options to remove them: by hand or herbicide. They could choose to manually remove them, but that process is strenuous and often backbreaking. On the other hand, if gardeners choose herbicides, they could unknowingly introduce toxic chemicals to waterways and aquatic life as well as butterflies, bees and earthworms, especially if used incorrectly.
There is a third option though – steam. In conjunction with Oakland County’s Environmental Sustainability Strategic Goal, landscaping services use steam to remove weeds that sprout throughout the campus grounds, including on lawns, pavement gaps, and garden beds. It’s the same kind of steam you’d use at home to iron a shirt or cook vegetables but at hotter temperatures.
During spring when the weeds are just starting to emerge, Oakland County groundskeepers bring out the Satusteam SW-900, which resembles a large power washer, to dehydrate the stems and leaves. They fuel the machine with less than a gallon of gasoline and fill the reservoir with 270 gallons of plain tap water. It boils the water to 230-240 Farenheit and releases saturated steam through the hose to the large triangular head. Groundskeepers use that head attachment to smother the weeds and emit low-pressured steam for 10 seconds.
However, some plant species can stand the initial heat and need follow-up treatments to completely die off.
“On annual weeds, such as shepherd’s purse and groundsel, the effects are immediate. The leaves wilt and turn black. On Canada thistle, it will turn the foliage black, and it wilts, but another plant emerges within a week. We treat these multiple times to achieve control. The weeds basically shrivel up and disappear. I have spoken to another user from New Jersey, and they are trying it on phragmites, which we have no shortage of on campus,” said Mark Baldwin, chief of landscape services.
After the unwanted plants shrivel up, groundskeepers increase the water pressure while decreasing the temperature and use the weed control machine as a hot-water power washer to blast away the remains. This is especially useful at the Oakland County Animal Shelter and Pet Adoption Center, where dogs could see potentially harmful weeds as tasty treats.
Since the Satusteam SW-900 is fast and user-friendly, groundskeepers can eradicate current plant invaders and suppress future ones. But the biggest benefit is that the steam machine does not use any chemicals, which means it is more versatile and safer than herbicidal treatments.
“We have definitely reduced the amount of herbicides we are using. A big advantage of the steam weeder is it can be used in any weather, such as rain or high winds, that would prevent herbicides from being applied. Because there are no pesticides involved, the operator does not need certification from the State of Michigan,” Baldwin said.
The initial purchase of the SW-900 was $26,316, including shipping. According to Baldwin, the facilities department plans to buy an additional head attachment for more targeted steaming.
“We are getting a spike so the steam can penetrate deeper and kill the roots,” Baldwin said.
And with a minor switch of the steamer’s tools, grounds crews are also using the light-weight machine to power wash sidewalks on the county campus without having to use any cleaning substances, just good old-fashioned H2O.
“It’s much easier on the knees,” said Greg Wheeler, an equipment operator in the Facilities Management and Operations Department, as he pulverized some thistle last week on the county campus. “Within a day this will shrivel up and you won’t even know it was here.”
In addition to the removal of invasive weeds, Oakland County’s grounds crew members have been transplanting and eliminating diseased and dying trees on campus.
“The trees that are being removed currently are Norway maples that are infected with a Verticillium fungus, so their long-term survival is in doubt. Pretty much all the trees had roots that were girdling the trunk,” he said.
Unfortunately, Norway Maple trees are invasive as well as the Bradford pear trees, which became a popular choice for landscaping due to their white flowers. These species tend to crowd out native plants and overtake areas.
“We’ve also removed all the Bradford pear trees that were growing on campus,” Baldwin said.
However, the ground won’t remain dormant for long. As he has promised to plant 2,027 trees by 2027, Baldwin and his team will introduce black hills spruce, eastern white pine, river birch, serviceberry, sugar maple and burr oak trees to replace the invasive trees.
“It does seem counterintuitive to plant new trees and then cut other ones down, but sometimes you have to bite the bullet, correct past mistakes and then not repeat them. I realized most of the struggling trees from the past aren’t worth the effort to try and save. Please be assured we are planting more trees than we are cutting down,” he said.
Mark Baldwin was recently named Proven Winners Certified Landscape Professional. He is also an International Society of Arboriculture (ISA) Certified Arborist, TRAQ Certified, Michigan Oak Wilt Qualified, Accredited Snow Contractors Association Certified.