Plants

Plants

Lesser Celandine, Ficaria verna

Plants on the DISC list included species that are non-native to Delaware, have the potential for widespread dispersal and establishment, can out-compete other species in the same area, and have the potential for rapid growth, high seed or propagule productions and establishment in natural areas.  Each species was chosen by a committee of experts in environmental science and botany after an intensive environmental assessment.

The first Delaware Invasive Species Council (DISC) assessment of invasive plants was conducted in 2003, and followed protocol developed by NatureServe. A second assessment was done in 2006, following the same protocol. After the 2006 assessment, DISC developed three invasive categories – widespread and invasive, restricted and invasive, and restricted and potentially invasive. In 2019, DISC recognized that a revision of the 2006 list of invasive plants was needed, and that the NatureServe protocol should be modified to make it more relative to the state of Delaware. The current assessment is based on this modified protocol and intended for educational purposes 

The protocols are documented in the Plant Species Assessment Protocol document.


Based on the expert assessments, an I-Rank, or invasive rank was determined based on expert responses denoting the level at which a species is invasive in the identified geographic area, in this case, the state of Delaware. These ranks are categorized by high, medium, low, and insignificant. If a species was ranked as high, medium, or low, they are deemed invasive to some degree by the experts and; therefore, are included in the current iteration of the DISC list of Invasive Plant Species. Species ranked as insignificant, were added to the DISC Watch List and will be reevaluated in two years when the list will again be revised. Additionally, for future revisions to the list, selected species thought to be invasive in Delaware will also be evaluated. In contrast to the 2006 DISC list of invasive plants, the new list includes only two categories – invasive and watch list. Below are the results.

Download the Current DISC Invasive Plant List Conclusion Document (January 2024)

DISC Invasive Plant List

Scientific and common names are based on: McAvoy, W.A. 2023. The Flora of Delaware Database. Delaware Division of Fish and Wildlife, Species Conservation and Research Program, Smyrna, Delaware.

SpeciesCommon Name
Acer palmatumJapanese maple
Acer platanoidesNorway maple
Acorus calamusEuropean sweetflag
Ailanthus altissimatree-of-heaven
Albizia julibrissinsilktree
Alliaria petiolatagarlic mustard
Alternanthera philoxeroidesalligatorweed
Ampelopsis glandulosaporcelain-berry
Aralia elataJapanese angelica tree
Artemisia vulgarismugwort
Arthraxon hispidus var. hispidusjoint-head arthraxon
Benthamidia japonicaKousa dogwood
Berberis thunbergiiJapanese barberry
Broussonetia papyriferapaper-mulberry
Cabomba carolinianaCarolina fanwort
Cardamine impatienstouch-me-not bittercress
Carex kobomugiAsiatic sand sedge
Celasrus orbiculatusAsian bittersweet
Cenchrus purpurascensChinese fountaingrass
Centaurea stoebe subsp. micranthosspotted knapweed
Cirsium arvenseCanada thistle
Clematis terniflorasweet autumn clematis
Commelina communisAsiatic dayflower
Conium maculatumpoison-hemlock
Convolvulus arvensisfield bindweed
Echinochloa crusgalli var. crusgallibarnyard grass
Egeria densaBrazilian waterweed
Elaeagnus umbellataautumn olive
Eragrostis curvulaweeping lovegrass
Euonymus alatuswinged euonymus
Euonymus fortuneiwinter creeper
Fallopia japonicaJapanese knotweed
Ficaria verna subsp. vernalesser celandine
Glechoma hederaceaground ivy
Hedera helixEnglish ivy
Hedera hibernicaAtlantic ivy
Hemerocallis fulvaorange day-lily
Humulus scandensJapanese hops
Hydrilla verticillatahydrilla
Ilex crenataJapanese holly
Iris pseudacorusyellow flag
Koelreuteria paniculatagolden rain tree
Lespedeza cuneataChinese bushclover
Leucojum aestivumsummer snowflake
Ligustrum obtusifolium var. obtusifoliumborder privet
Ligustrum sinenseChinese privet
Ligustrum vulgarecommon privet
Lonicera japonicaJapanese honeysuckle
Lonicera maackiiAmur honeysuckle
Lonicera morrowiiMorrow’s honeysuckle
Lonicera tataricaTartarian honeysuckle
Ludwigia grandifloraerect water primrose seedbox
Ludwigia peploides var. glabrescenscreeping water primrose seedbox
Lysimachia nummulariacreeping jenny
Lythrum salicariapurple loosestrife
Microstegium vimineumJapanese stilt-grass
Miscanthus sinensisChinese silvergrass
Morus albawhite mulberry
Murdannia keisakmarsh dewflower
Myriophyllum aquaticumparrot’s-feather water-milfoil
Myriophyllum spicatumEurasian water-milfoil
Narcissus pseudonarcissusdaffodil
Oplismenus undulatifoliuswavyleaf basketgrass
Pachysandra terminalisJapanese pachysandra
Paulownia tomentosaprincess-tree
Perilla frutescensperilla
Persicaria longisetalongbristle smartweed
Persicaria perfoliatamile-a-minute-vine
Phalaris arundinaceareed canary-grass
Phellodendron amurenseAmur cork tree
Phragmites australis subsp. australisEuropean reed
Phyllostachys aureagolden bamboo
Pinus thunbergianaJapanese black pine
Prunus aviumsweet cherry
Prunus subhirtellaweeping Higan cherry
Pueraria montana var. lobatakudzu
Pyrus calleryanaBradford pear
Quercus acutissimasawtooth oak
Reynoutria japonica var. japonicaJapanese knotweed
Rhamnus davuricalance-leaf buckthorn
Rhodotypos scandensblack jetbead
Robinia pseudoacaciawhite flowered locust
Rosa multifloramultiflora rose
Rubus parvifoliusthree-leaf blackberry
Rubus phoenicolasiuswineberry
Schoenoplectiella mucronataalien bulrush
Stellaria mediacommon chickweed
Tripidium ravennaeRavenna grass
Typha angustifolianarrowleaf cattail
Urtica dioica subsp. dioicastinging nettle
Viburnum dilatatumlinden viburnum
Viburnum plicatumdoublefile viburnum
Viburnum setigerumtea viburnum
Viburnum sieboldiiSiebold’s viburnum
Vinca minorcommon periwinkle
Vitex rotundifoliabeach vitex
Wisteria sinensisChinese wisteria

DISC Invasive Plant Watch List

Scientific and common names are based on: McAvoy, W.A. 2023. The Flora of Delaware Database. Delaware Division of Fish and Wildlife, Species Conservation and Research Program, Smyrna, Delaware.

SpeciesCommon Name
Abies firmaMomi fir
Akebia quinatafive-leaf akebia
Buddleja davidiibutterfly bush
Corydalis incisapurple corydalis
Deutzia crenata var. crenataDeutzia
Fatoua villosamulberry weed
Galanthus nivalissnowdrop
Lespedeza thunbergiiThunberg’s bushcover
Lilium lancifoliumtiger lily
Lotus corniculatusbirds-foot trefoil
Mahonia bealeiChinese mahonia
Malus toringoToringo crabapple
Pistia stratioteswater-lettuce
Pourthiaea villosaAsian photinia
Spirea japonicaJapanese spirea
Trapa natanswater chestnut