Sudbury-Assabet-Concord River Watershed

Priority Invasives

The Priority Invasive Species List

This current list of selected, well established invasive species (dubbed the “Sour 16”) are considered the worst invasive species in the SuAsCo watershed by the SuAsCo CISMA. These species are heavy invaders and resistant to most efforts to eradicate them. However, these species are certainly not the only invasive species. There is an ongoing competition for the worst ones.

The demands on personnel and finance tend to prevent their complete removal. Attempts to remove these species tend to be focused on preventing their spread and rely on biological and chemical controls to cover large areas. It is a constant battle to keep them under control and we recommend any landowners in the watershed remove them when discovered by the best means they have available.

The individual Priority invasive species are listed below and on the side menu. The common names are links to specific information on each species.


Common Name
Genus-Species Name

Autumn Olive shrub
Elaeagnus umbellata
Photo of Black Swallowwort
Cynanchum louiseae syn: Cynanchum nigrum
Burning bush
Euonymus alatus
Bush Honeysuckle
Lonucera maackii, Lonicera morrowii, Lonicera tatarica, Lonicera x bella
Phragmites
Phragmites australis
Myriophyllum spicatum
Photo of Garlic Mustard
Alliaria petiolata
Frangula alnus
Barberry berries
Berberis thunbergii
Japanese Knotweed leaves
Fallopia japonica
Multiflora Rose Blossoms
Rosa multiflora
Oriental Bittersweet
Celastrus orbiculatus
Purple Loosestrife
Lythrum salicaria
Spotted Knapweek
Centaurea stoebe
Tree-of-heaven
Ailanthus altissima
Water Chestnut
Trapa natans
Wild Chervil
Anthriscus sylvestris (L.) Hoffm.