In recent years it has become an invasive species in parts of the eastern United States; in Canada its cultivation is prohibited as the species can act as a host for "Puccinia graminis" (black rust), a rust disease of wheat.
It has become an invasive species in parts of the eastern United States. This was in recent years. As the species can act as a host for "Puccinia graminis" (black rust). This was what its cultivation is prohibited in Canada. A host for "Puccinia graminis" (black rust) are a rust disease of wheat.