Delaware Invasive Species Council

Delaware's Invasive Plant List

 WIDESPREAD INVASIVE PLANTS 

• Multiflora rose, Rosa multiflora
• Japanese honeysuckle, Lonicera japonica
• Oriental bittersweet, Celasrus orbiculata
• Japanese stilt grass, Microstegium vimineum
• Japanese knotweed, Polygonum cuspidatum
• Autumn olive, Elaeagnus umbellata
• Norway maple, Acer platanoides
• Common reed, Phragmites australis
• Hydrilla, Hydrilla verticillata
• Morrow's honeysuckle, Lonicera morrowii
• Mile-a-minute weed, Polygonum perfoliatum
  
• Yam-leaved clematis, Clematis terniflora
• Privet, several species
• European sweetflag, Acorus calamus
• Wineberry, Rubus phoenicolasius

• Japanese barberry, Berberis thunbergii
• Periwinkle, Vinca minor
• Garlic mustard, Alliaria petiolata
• Winged euonymus, Euonymus alata
• Porcelain berry, Ampelopsis brevipedunculata
• Bradford pear, Pyrus calleryana
• Marsh dewflower, Murdannia keisak
• Lesser celandine, Ranunculus ficaria
• Purple loosestrife, Lythrum salicaria
• Reed canarygrass, Phalaris arundinacea
• Amur honeysuckle, Lonicera maackii
• Tartarian honeysuckle, Lonicera tatarica
• Tree of heaven, Ailanthus altissima
• Spotted knapweed, Centaruea biebersteinii

RESTRICTED AND POTENTIALLY INVASIVE PLANT 

• Butterfly bush, Buddleia davidii

Plants on the List:

1. A species is non-native to Delaware, has the potential for widespread dispersal and establishment, can out-compete other species in the same area, and has the potential for rapid growth, high seed or propagule productions and establishment in natural areas.
2.  A species is chosen by a committee of experts in environmental science and botany, as well as representatives of State agencies and the Nursery and Landscape Industry.
3. An environmental assessment was conducted on each of the plants listed, and placement on the list results from review of the scientific literature, as well as a consensus of expert opinions.  Plants on the list are ordered from highest to lowest invasiveness.
   
4. Plants on the list should not be planted, under any circumstances, and should be removed from properties as feasible.
5. Listed plants that are currently in the nursery trade should be phased out of inventory and production.
6. Homeowners are encouraged to ask nurseries, garden centers, and landscapers for non-invasive plants, preferably natives.
7. Widespread and Invasive plants are currently invasive in the landscape, cause serious management concerns or pose a serious threat to the biological diversity of Delaware.
8. Restricted and Invasive plants are equally problematic.  However, they have a more localized distribution in Delaware.

 Publications Available:

Plants for a Livable Delaware

 Mistaken Identity:

Invasive Plants and their Native Look-alikes