Pennsylvania prohibits the sale of Ravenna grass and two types of buckthorn trees
The state Department of Agriculture has added three species to the state’s list of noxious weeds, which are non-native invasive plants that cannot be sold or grown.
New plants added to the list are ravennae grass (Tripidium ravennae) also known as hardy pampas grass, brilliant buckthorn (Frangula alnus), and common buckthorn (Rhamnus cathartica).
In the southwestern part of the state, the three banned species are present in the landscape but not widespread in natural areas, said Amy Jewett, invasive species coordinator for the Western Pennsylvania Conservancy.
“This ban is a huge win,” she said. “These invasive plants will no longer enter the environment and will not spread into natural areas.”
However, since the plants, with the exception of common buckthorn, are sold commercially, they are found in residents’ yards.
Ravenna grass is a perennial ornamental grass that grows 6 feet tall and is commonly sold in nurseries. Their unnatural plumes choke out native plants and spread easily.
Not all pampas grass species are banned, said Shannon Powers, a spokeswoman for the Department of Agriculture.
Penn State Extension Master Gardener Louisa Fordyce has some distant relatives of the plant in her yard.
“I have zebra grass, which is getting overgrown, but it’s not spreading anywhere,” she said. “I also have perennial Karl Foerster grass; it just stays in a clump. But true pampas grass has very fertile seeds, and can be spread easily by wind and birds, which is where the problem can come from.”
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Glossy buckthorn is a small tree or shrub that produces berries that birds eat and disperse seeds. This plant “is widespread in wetlands,” according to the Ministry of Agriculture.
Glossy buckthorn has a commercially available cultivar called ‘Rhamnus Fine Line’. The administration has an exemption procedure for breeders who own the rights to varieties proven to be sterile. The ban on sales begins in 2023.
Common buckthorn is a non-native invasive tree and is not sold commercially. This tree forms a dense forest, suffocating local ecosystems, according to the administration.
Local gardeners should consider removing these plants if they haven’t already, given their vigorous growth, Powers said.
Drivers on the Route 66 Bypass will be able to see part of the rationale behind banning the species, such as a certain variety of Callery pear (Pyrus calleryana), later this year, Fordyce said.
“If you travel the Route 66 bypass from Delmont to Greensburg in the spring, look at the white-flowered trees on the hillsides. These are Callery or Bradford pears, and it is doubtful they were planted in those areas,” she said.