Massachusetts enforces strict regulations to safeguard its ecosystems from invasive species. These plants threaten local habitats by outcompeting native vegetation and disrupting biodiversity. To preserve the environment, the state prohibits cultivating certain plants. Below is a list of species banned under the Massachusetts Prohibited Plant List that gardeners and landscapers should avoid.
Japanese Knotweed (Fallopia japonica)

Japanese Knotweed is an aggressive invasive species capable of dominating landscapes, displacing other plants, and taking over entire areas. This aggressive growth triggers a domino reaction, forcing native species, including insects and birds, to abandon the area due to the loss of their natural habitats. Its resilience and rapid spread make it a significant threat to Massachusetts ecosystems, leading to its ban.
Purple Loosestrife (Lythrum salicaria)

Purple Loosestrife is often admired for its beautiful purple flowers, but this plant wreaks havoc on wetlands. It outcompetes native plants that are crucial for maintaining the ecosystem. Its dense growth chokes off waterways, causing issues for aquatic life and reducing biodiversity. Massachusetts has outlawed its sale to protect local wetlands from further damage.
Autumn Olive (Elaeagnus umbellata)

Autumn Olive is a fast-growing shrub or small tree, known for its adaptability to different soil conditions, allowing it to spread rapidly in diverse environments. By outcompeting and displacing native plants, it alters local ecosystems. It achieves this by shading out other vegetation and altering soil chemistry through a process known as allelopathy.
Yellow Flag Iris (Iris pseudacorus)

Yellow Flag Iris is a wetland species known for its rapid spread, utilizing both seeds and rhizomes. While it’s visually appealing, it disrupts the balance of native aquatic ecosystems. This invasive plant thrives in wetland areas, outcompeting native species and reducing biodiversity, mainly along riverbanks and marshes in Massachusetts.
Japanese Barberry (Berberis thunbergii)

Though popular in landscaping for its hardiness, Japanese Barberry poses severe ecological and health risks. Research from Connecticut highlights its role in fostering black legged ticks, which thrive in the humid microclimate it creates. Areas with uncontrolled barberry had up to 120 infected ticks per acre, compared to just 10 in regions without the plant.
Tartarian Honeysuckle (Lonicera tatarica)

Tartarian Honeysuckle was once popular for landscaping, but its aggressive nature has led to its ban in Massachusetts. It outcompetes native shrubs and plants, reducing biodiversity in forested areas. The plant’s ability to spread quickly, along with its dense, shade-producing growth, gives it a competitive advantage over native vegetation.
Common Buckthorn (Rhamnus cathartica)

Common Buckthorn is a fast-growing shrub that disrupts local ecosystems by forming dense thickets. Its dense growth blocks sunlight, preventing native plants from thriving. The shrub also produces emodin and anthraquinones, toxic compounds that can cause nausea, vomiting, and diarrhea if its berries are ingested.
Giant Hogweed (Heracleum mantegazzianum)

Giant Hogweed poses both environmental and health risks. Its toxic sap contains furanocoumarins, chemicals that make skin highly sensitive to sunlight. Sun exposure after contact with the sap can trigger phytophotodermatitis, a severe skin reaction causing painful blisters and inflammation.
Mile-a-Minute Vine (Persicaria perfoliata)

As the name suggests, Mile-a-Minute Vine is known for its rapid growth. It can cover large areas quickly, smothering native plants and trees. The plant’s ability to spread by seeds transported by animals, wind, and water contributes to its success as an invasive species in Massachusetts.
Kudzu (Pueraria montana)

Known for its rapid growth, Kudzu is a vine that can quickly cover entire buildings, trees, and fences. Originally introduced to control erosion, it has now become one of the most notorious invasive plants in the United States. It smothers other plants and trees, causing them to die from a lack of sunlight.
Tree of Heaven (Ailanthus altissima)

Tree-of-Heaven is an aggressive, fast-growing tree that spreads through root suckers, making it hard to control once established. This tree invades disturbed areas, urban environments, and forests, displacing native species. It thrives in diverse habitats throughout Massachusetts, thanks to its adaptability to poor soil conditions.
Bamboo (Phyllostachys spp.)

Bamboo, especially the running variety, is banned in Massachusetts due to its invasive nature. It spreads rapidly through rhizomes, making it difficult to control once established. Bamboo can damage foundations, sidewalks, and other structures. Its ability to quickly form dense clumps often leads to its dominance in local ecosystems, pushing out native species and disrupting local habitats.
Witchweed (Striga spp.)

Witchweed is a parasitic plant that targets essential crops like corn, sorghum, sugar cane, and rice. It distinguishes itself from other weeds by attaching to the roots of its host plants, extracting nutrients directly from them. While the plant typically has red flowers, occasional yellow blooms can also appear. Witchweed doesn’t just compete for resources; it directly damages crops, weakening them and reducing yields.
Norway Maple (Acer platanoides)

Due to its resilience and adaptability, Norway Maple is a commonly planted tree in urban and suburban areas. However, it has become a concern for local ecosystems. Its dense canopy can limit sunlight for understory plants, and its rapid growth allows it to dominate areas where it takes root. The wind easily disperses its seeds, contributing to its invasive spread.
Benghal Dayflower (Commelina benghalensis)

First recorded in Florida in 1928, the USDA designated Benghal Dayflower a noxious weed in 1983. This hardy tree outcompetes native plants by draining water and nutrients, and its thorny branches make it challenging to manage. Its presence on nursery properties can trigger quarantines, making early identification and control crucial.