UNIVERSITY PARK – Penn State’s College of Agricultural Sciences has earned an international reputation for cutting-edge research revolving around growing beneficial plants – ranging from genetic work with cocoa in South America and developing bean varieties that can flourish on infertile soils in Africa to developing blight-resistant potatoes and tomatoes for the northeastern United States.
But some of the most important activities undertaken by the college these days include preventing and controlling the growth of unwanted plants and limiting the economic damage they do. One such project that has spanned more than two decades is a collaboration with Pennsylvania’s Department of Transportation to battle invasive weeds that are clogging and choking the rights of way along the commonwealth’s roads.
“Vegetation problems, primarily caused by invasive plants, are increasing but PennDOT’s resources are not,” according to Art Gover, a research-support associate who spearheads Penn State’s participation in the project. “There are many problems facing road managers – people call them when they hit potholes or when the road is flooding because the drainage system is failing – but the phone doesn’t ring much with complaints about roadside vegetation.
“It’s a problem that the public doesn’t think about,” he added. “That’s because unless there is an obvious problem, such as signs being obscured, most people think green is good. One of the issues we need to overcome by informing the public about invasive species is the idea that vegetation is always beneficial. We aren’t used to regarding plants as pollution.”
But invasive species such as tree of heaven – an Asian plant which was introduced as an urban ornamental tree from European gardens in 1784 – are making PennDOT’s job tougher. The transportation department is obligated to maintain rights of way – by mowing and tree cutting to insure adequate sight distances, and otherwise protecting the integrity of the corridors along 40,000 miles of roadways.
“In terms of invasive plants, there is a lot more of what was here 30 years ago, and there are a lot more invasive species than there used to be,” said Michael Maurer, a PennDOT specialist who has been battling roadside vegetation for more than three decades. “Our efforts are multi-faceted and involve tree removal and side trimming, tree encroachment control, hydro-seeding to install competing vegetation, mowing, landscaping and a maintenance pesticide program. We work around guiderails, bridge abutments and signage.”
Maurer is comforted by Penn State’s support. “I value the fact that I can pick up the phone and have the expertise of the College of Agricultural Sciences at my fingertips,” he said. “They provide us with soil analysis, diagnosis of tree diseases, testing for herbicides, advice on herbicide-application rates, chemistry and documentation about what works best for herbicide-application crews.
“I think it is the best money spent in our roadside program because it gives us both resources and credentialed experts to solve problems,” Maurer added. “It brings a lot of credibility to the table when I can say, ‘Penn State recommended this course of action,’ to the owner of property beside a right of way. The college’s experts provide unbiased opinions.”
Herbicide application has become a major issue when dealing with invasive plants because some of the most aggressive species, such as kochia, are becoming resistant to herbicides, and that makes them much more expensive to control. Other species of concern, according to Gover and Maurer, are knotweed (both giant and Japanese varieties), poison hemlock, a multitude of thistles (Canada thistle is the worst), yellow and giant foxtail, giant hogweed (a European native that has made the state and federal noxious weed lists), multi-flora rose, autumn olive and exotic honeysuckles.
“There is no other university in the Northeast that has a vegetation management program like Penn State’s,” Gover said. “One thing that helps us is we are out there doing research. The bulk of our sites are replicated trials where we are testing herbicides and techniques. In addition, the University provides training, workshops and outreach on invasive plant-control.”
Invasives growing from rights of way onto private properties has become an issue for PennDOT, Gover points out. “We didn’t have to contend with these species before, and we need a new conservation ethic about biological pollution – alerting people that there is this growing problem with invasive plants,” he explains. “PennDOT is wrestling with being a good neighbor and contending with invasives on rights of way, not allowing these plants to breed and spill over onto adjacent private properties.”