The state of Maine has enacted new rules that ban the sale and distribution of 33 plants that have been deemed invasive, and therefore pose problematic to the state’s natural habitats.

The Department of Agriculture, Conservation and Forestry (DACF) announced the invasive terrestrial plant rules in a press release last week, identifying the plants that would be impacted. Invasive plants are non-native species that have spread into native habitats, such as forests or fields, that can become dominant and disruptive to native species, according to DACF.

“The plants on the list have invaded farms, fields, forests and wetlands throughout the state,” Commissioner Walt Whitcomb said in the release. “In many places they have come to dominate forests, wetlands, fields and local landscapes, excluding native plants that support our economy and natural areas.”

The mission to identify and eradicate invasive species is a collaborative effort between DACF, the Maine Forest Service, Public Lands and the Natural Areas Program. The list of invasive species was reviewed and approved by a committee of horticulture professionals, land managers, foresters, and wildlife biologists.

This is the first time the state has barred the sale and distribution of invasive species, according to Maine State Horticulturist, Gary Fish. However, there are existing federal bans on terrestrial and aquatic invasive species.

According to Fish, invasive species pose a threat to natural habitats, or minimally managed habitats, because of how quickly they can spread and grow. Spread of the plants is often unintentional, occurring by birds, animals, or the wind, which can pick up the plant’s seeds and spread them to other places.

“They grow so quickly they completely overtake the forested areas so that you actually can’t even get the forest to regenerate,” Fish said. “A number of these [species] end up coming up in farmers’ pastures and fields and make it difficult to keep [the spaces] open.”

Several plants on the list are still in demand for creating landscapes, according to Fish, including the Norway maple, burning bush, and privet, a type of hedge. However he said there are native varieties that are related to these species which wouldn’t pose an invasive risk.

Fish stressed that there are many alternative plants available that can be used to replace the list of prohibited species. A list of resources to find comparable plants is available on the DACF website.

The new rules only bar the prohibited species from being distributed or sold, and do not require the removal of the species if already planted. While the rules went into effect on Jan. 14, the prohibition of sale will not begin until Jan. 1, 2018.