Invasive plant list

"The Bad Plant" List

Plants that have been assessed and categorized by the Rhode Island Invasive Species Council, as of 2/28/2001

Note: This list does NOT include every plant that is invasive in Rhode Island, but it is a list of those plants that have been assessed to date, using the attached criteria.

Widespread and Invasive:
Cabomba caroliniana; Fanwort
Celastrus orbiculatus; Asiatic Bittersweet
Elaeganus umbellata; Autumn Olive
Lonicera japonica; Japanese Honeysuckle
Lythrum salicaria; Purple Loosestrife
Polygonum cuspiatum; Japanese Knotweed
Potamogeton crispus; Curly Pondweed
Rhamnus cathartica; Common Buckthorn
Rosa multiflora; Multiflora Rose
Vincetoxicum nigurm; Black Swallowwort

Restricted and Invasive:
Ailanthus altissima; Tree of Heaven (+spreading)
Alliaria petiolata; Garlic Mustard (+spreading)
Ampelopsis brevipedunculata; Porcelain Berry
Myriophyllum heterophyllum; Variable Water-milfoil
Ranunculus ficaria; Lesser Celandine
Rorippa nasturtium-aquaticum, Watercress
Rubus phoenicolasius; Wineberry (need more information on its spread in RI)
Vincetoxicum rossicum, White Swallowwort

Agreed to be invasive but need more information:
Acer platanoides; Norway Maple (fits Criteria 1-9 and is widespread; need to assess reproductive capabilities of cultivars and hybrids)
Berberis thunbergii; Japanese Barberry (fits Criteria 1-9 and is widespread; need to assess reproductive capabilities of cultivars and hybrids)
Euonymus alatus; Burning bush (fits Criteria 1-9 and is widespread; need to assess reproductive capabilities of cultivars and hybrids)
Lonicera morrowii and Lonicera x Bella; Morrow and Bella Honeysuckle (but need to assess reproductive capabilities of cultivars and hybrids)

Needs more research and observation/monitoring:

Many of these species are known to be invasive in neighboring states.

Acer pseudoplatanus; Sycamore Maple
Allium vineale; Field Garlic
Berberis vulgaris; European Barberry
Campsis radicans, Trumpet Vine
Clematis paniculata; Sweet Autumn Clematis
Cytisus scoparius; Scotch Broom
Daucus carota, Queen Anne’s Lace
Elaeganus angustifolia; Russian Olive
Euonymus fortunei; Wintercreeper
Hesperis matronalis; Dame’s Rocket
Iris pseudoacorus; Yellow Flag
Kochia scoparia; Summer Cypress
Ligustrum species, Privet (fits Criteria 1 – 5 and is spreading; we need to know which species are the ones that’s naturalize and spread.(
Miscanthus sinensis; Maiden Grass
Morus alba; White Mulberry
Myosotis scropioides, True Forget Me Not
Phellodendron japonicum; Amur Corktree
Phagmites australis, Common Reed (need to assess if there are native, non-aggressive populations)
Pinus thunbergiana; Japanese Black Pine
Polygonum sachalinense, Princess Feather
Quercus robur, English Oak
Rhamnus frangula; Glossy Buckthorn (fits Criteria 1 – 5 and is spreading; need assessment of the cultivars)
Robinia pseudoacacia; Black Locust
Rosa rugosa; Beach Rose (fits Criteria 1 – 9; suggested ‘Fast Track” monitoring)
Yucca filamentosa, Spanish Bayonet

Potentially Invasive Species:

There are invasive in other states but have not yet become so in Rhode Island.
Eichornia crassipes; Water Hyacinths
Egeria densa; Brazilian Waterweed
Hydrilla verticillata; Hydrilla
Lysimachia nummularia; Moneywort
Microstegium vimineum; Japanese Stiltgrass
Myriostegium spicatum; Eurasian Water-milfoil
Najas minor; Eutrophic Water-nymph
Pistia stratoites; Water Lettuce
Polygonum perfoliatum; Mile a minute Weed
Trapa natans; Water-chestnut

Weedy: (plants of disturbed areas; do not appear to be affecting minimally managed habitats). This list is not even close to all of the non-native “weedy” plants in Rhode Island. The ones below were in the original list assessed by the RIISC during 2000; if a plant wasn’t on that list or wasn’t brought up subsequently as potentially meeting the criteria for an invasive species in the state; it is not included here.

Aegopodium podagaria; Goutweed
Bromus tectorum; Drooping Brome Grass
Centaurea nigra, C. dubia, C. maculosa; Knapweeds
Cirsium arvense; CanadaThistle
Coronilla varia; Crown Vetch
Euphorbia cyparissias; Cypress Spurge
Glechoma hederacea; Ground Ivy
Lamiun amplexicaule; Henbit
Lamiun purpureum; Purple Dead Nettle
Rumex acetosella; Sheep Sorrel
Solanum dulcamara; European Nightshade

Rhode Island Invasive Species Council
Lisa Gould, Coordinator
URI Cooperative Extension/ Rhode Island Natural History Survey

Cristin M. Larson; The Garden Consultant and Landscape Design