Invasive Species

When plants are introduced to a new location, either intentionally or accidentally, they can spread prolifically, out-compete native species for resources, and eventually even dominate the landscape. Biologists are studying the mechanisms underlying a taxon’s ability to become invasive, but it can be difficult to predict whether or not a species will become invasive in a new habitat. With an increased awareness about the environmental and economic threats posed by invasive species, the Chicago Botanic Garden has expanded and strengthened its invasive plant policy.  The Garden aims to strengthen its role as a conservation leader without compromising its horticultural mission or the beauty of its landscapes.

Chicago Botanic Garden Status:

R Remove as soon as possible, including all cultivars, and/or do not add to collection in future
P Phase out (species that pose a lesser invasive risk, form significant structural features in landscape, and will be time-consuming to replace will be phased out over a five- to ten-year period)
E Evaluate species and cultivars, then remove invasive taxa
W Watch and monitor for signs of invasiveness

 

Scientific Name
Common Name
Plan

Alternatives

Acer ginnala
Amur maple
P Acer rubrum (red maple), Quercus alba (white oak)
Acer platanoides
Norway maple
R Acer x freemanii 'Marmo' (Marmomaple), Acer miyabei (Miyabe maple), Acer rubrum (red maple), Quercus alba (whiteoak)
Aegopodium podagraria
Goutweed
R Asarum (wild ginger), Epimedium spp. (barrenwort), Glandularia canadensis (mock rose vervain), Hosta (hosta)
Agropyron repens
Quack grass
R Panicum virgatum cvs. (switch grass), Sporobolus heterolepsis (prairie dropseed)
Ailanthus altissima
Tree-of-heaven
R Gymnocladus dioicus (Kentucky coffee tree), Celtis occidentalis (Hackberry), Styphnolobium (formerly Sophora) japonica (Pagoda tree)
Alliaria petiolata
Garlic mustard
R Not used ornamentally
Alnus glutinosa
European black alder
P Celtis laevigata (sugarberry), Celtis occidentalis (common hackberry), Nyssa sylvatica (black tupelo)
Alternanthera philoxeroides
Alligator weed
R Not used ornamentally
Ampelopsis brevipedunculata
Porcelainberry vine
R Clematis spp. (clematis)
Anthriscus sylvestris
Wild chervil
R Aruncus spp. (goatsbeard), Achillea spp. (yarrow)
Arctium minus
Lesser burdock
R Not used ornamentally
Artemisia absinthium
Wormwood
R Brunnera macrophylla 'Jack Frost' (Siberian bugloss), Pulmonaria 'Silver Shimmers' (lungwort), Senecio cineraria (dusty miller), Perovskia atriplicifolia (Russian sage)
Artemisia vulgaris
Mugwort
R  
Azolla spp.
Water fern
R Lemna minor (lesser duck weed)
Berberis thunbergii
Japanese barberry
R Physocarpus opulifolius (ninebark), Ribes odoratum (clove currant)

Berberis koreana
Korean barberry

R Physocarpus opulifolius (ninebark), Ribes odoratum (clove currant)

Berberis koreana x B. thunbergii (incl. 'Tara' cv.)
Hybrid barberry

R Physocarpus opulifolius (ninebark), Ribes odoratum (clove currant)

Berberis thunbergii
Japanese barberry

R Physocarpus opulifolius (ninebark), Ribes odoratum (clove currant)
Berberis vulgaris
European barberry
R Physocarpus opulifolius (ninebark), Ribes odoratum (clove currant)
Bromus inermis
Smooth brome
R Not used ornamentally.
Butomus umbellatus
Flowering rush
R Juncus effusus (common rush), Sagittaria, Schoenoplectus americanus (bulrush)
Cabomba caroliniana
Fanwort
R Not used ornamentally
Calamagrostis brachytricha
Reed grass
R  
Carduus nutans
Nodding plumeless thistle
R Echinacea spp. (coneflower), Silphium spp. (rosinweed, prairie dock, compass plant)
Celastrus orbiculatus
Oriental bittersweet
R Aristolochia durior (Dutchman's pipe), Celastrus scandens (American bittersweet)
Centaurea maculosa
Spotted knapweed
R Echinacea spp. (coneflower), Silphium spp. (rosinweed, prairie dock, compass plant)
Cirsium arvense
Canada thistle
R Echinacea spp. (coneflower), Silphium spp. (rosinweed, prairie dock, compass plant)
Cirsium palustre
Marsh plume thistle
R (see C. arvense)
Cirsium vulgare
Bull thistle
R (see C. arvense)
Conium maculatum
Poison hemlock
R Aruncus spp. (goatsbeard), Achillea spp. (yarrow)
Coronilla varia
Crown vetch
R Vicia americana (purple vetch) Tephrosia virginiana (Goat’s-rue), Phlox subulata (creeping phlox)
Cotoneaster multiflorus
Many-flowered cotoneaster
P Physocarpus opulifolius (ninebark), Ribes odoratum (clove currant)
Daucus carota
Queen Anne's lace
R Aruncus spp. (goatsbeard), Achillea spp. (yarrow)
Dioscorea batatas
Chinese yam
R No ornamental alternative; used medicinally
Dipsacus laciniatus
Cutleaf teasel
R Echinacea spp. (coneflower), Rudbeckia spp. (black-eyed Susan)
Dipsacus sylvestris
Teasel
R (see D. laciniatus)
Duchesnia indica
Wild strawberry
R Waldsteinia ternata (barren strawberry)
Echinops sphaerocephalus
Globe thistle
R Liatris spp. (blazing star), Monarda spp.(beebalm), Phlox spp.(phlox), Salvia spp. (sage), Thalictrum spp.(meadowrue), Veronica spp. (speedwell)
Egeria densa
Brazilian elodea
R Elodea canadensis (water weed)
Eichornia crassipes
Water hyacinth
R No ornamental alternative
Elaeagnus umbellatus
Autumn olive
R Aesculus parviflora (bottlebrush buckeye), Aronia melanocarpa (black chokeberry), Corylus americana (American filbert)
Epilobium hirsutum
Hairy fireweed
R (see E. sphaerocephalus)
Euonymus alatus
Winged euonymus
R Euonymus americanus (American strawberry bush), Itea virginica (Virginia sweetspire), Rhus copallina var. latifolia 'Morton' (Prairie Flame shining sumac)
Euonymus europeaus
European spindletree
R Euonymus americanus (American strawberry bush), Itea virginica (Virginia sweetspire)
Euonymus fortunei
Wintercreeper
R Asarum spp.(ginger), Helleborus spp. (hellebore)
Euphorbia cyparissias
Cypress spurge
R Origanum laevigatum (ornamental oregano), selected Sedum spp. (stonecrop)
Euphorbia esula
Leafy spurge
R Aurinia saxatilis (basket-of-gold)
Festuca elatior (=F. arundinacea)
Tall fescue
R Not used ornamentally
Festuca pratense
Meadow fescue
R Not used ornamentally
Glechoma hederacea
Ground ivy
R Not used ornamentally
Hemerocallis fulva (locally invasive)
Tawny daylily
R (wild type only) Hemerocallis hybrids (daylily), Lilium spp. & cvs. (lily), Papaver orientale (Oriental poppy)
Heracleum mantegazzianum
Giant hogweed
R Aruncus spp. (goatsbeard), Achillea spp. (yarrow)
Hesperis matronalis
Dame's rocket
R (See E. sphaerocephalus)
Hippophae rhamnoides
Common sea buckthorn
R Shepherdia argentea (buffaloberry)
Hydrilla verticillata
Hydrilla, water thyme
R Not used ornamentally
Hydrocharis morsus-ranae
European frog-bit
R Native Nuphar (yellow pond lily) and Nymphaea (waterlily)
Hypericum perforatum
Common St. Johnswort
R Other Hypericum spp. (St. Johnswort)
Inula helenium
Horse-heal
R Heliopsis spp. (false sunflower), Helianthus spp. (sunflower), Coreopsis spp. (tickseed)
Ipomoea aquatica
Water spinach
R Justicia americana (American water willow)
Iris pseudacorus
Yellow flag iris
R Iris fulva 'Lois Yellow' (copper iris), Iris virginica var. shrevii (interior blue flag iris)
Lapsana communis
Nipplewort
R  
Lespedeza cuneata
Chinese bush clover
R Baptisia spp. (wild indigo)
Leymus arenarius
Blue lyme grass
R Ammophila breviligulata (American beach grass)
Ligustrum obtusifolium
Border privet
P Physocarpus opulifolius (ninebark), Ribes odoratum (clove currant)
Ligustrum vulgare
Common privet
P Physocarpus opulifolius (ninebark), Ribes odoratum (clove currant)
Linaria vulgaris
Butter-and-eggs
R Antirrhinum majus cvs. (snapdragons), Calibrachoa cvs. (million bells), Digitalis spp. (foxglove), Nemesia fruticans cvs. (nemesia)
Lonicera x bella
Bell's honeysuckle
R Amelanchier spp. & cvs. (serviceberry), Calycanthus floridus (Carolina allspice), Diervilla spp. (bush honeysuckle)
Lonicera japonica
Japanese honeysuckle
R Clematis spp. (clematis), native Lonicera spp. (native honeysuckles)
Lonicera maackii
Amur honeysuckle
R Amelanchier spp. & cvs. (serviceberry), Calycanthus floridus (Carolina allspice), Diervilla spp. (bush honeysuckle)
Lonicera morrowii
Morrow's honeysuckle
R Amelanchier spp. & cvs. (serviceberry), Calycanthus floridus (Carolina allspice), Diervilla spp. (bush honeysuckle)
Lonicera tatarica
Tatarian honeysuckle
R Amelanchier spp. & cvs. (serviceberry), Calycanthus floridus (Carolina allspice), Diervilla spp. (bush honeysuckle)
Lotus corniculatus
Bird's-foot trefoil
R Waldsteinia ternata (barren strawberry), Chrysogonum virginianum (green and gold) for groundcovers; Thermopsis caroliniana (Carolina lupine), Baptisia sphaerocarpa (yellow wild indigo) for a more upright plant
Lysimachia nummularia
Moneywort
R Chrysogonum virginianum (green and gold), Origanum laevigatum (ornamental oregano)
Lysimachia verticillata
Whorled loosestrife
R Oenothera fruiticosa (also known as Oenothera tetragona [sundrops]), Asclepias incarnata (swamp milkweed), Liatris spp. (blazing star), Physostegia virginiana 'Vivid' (obedient plant)
Lythrum salicaria
Purple loosestrife
R Oenothera fruiticosa (also known as Oenothera tetragona [sundrops]), Asclepias incarnata (swamp milkweed), Liatris spp. (blazing star), Physostegia virginiana 'Vivid' (obedient plant)
Malus spp. (crabapples)
Crabapple
E, I Crataegus spp. (hawnthorn species), Prunus serotina (black cherry)
Melilotus alba
White sweet-clover
R Baptisia spp. (wild indigo)
Melilotus officinalis
Yellow sweet- clover
R Baptisia spp. (wild indigo)
Microstegium vimineum
Japanese stilt grass
R Not used ornamentally
Miscanthus sacchariflorus
Amur silver grass
R (see A. repens)
Miscanthus sinensis
Chinese silver grass, Autumn Red Miscanthus, Flame Grass, Eulalia, Maiden Grass, Zebra Grass 
R (exempted cultivars are M.s. ‘Silberpfeil,’ ‘Hinjo’ and Miscanthus x giganteus) (see A. repens)
Morus alba
Mulberry
P Crataegus spp. (hawthorn species), Prunus serotina (black cherry)
Myriophyllum aquaticum
Parrot feather
R Elodea canadensis (water weed)
Myriophyllum spicatum
Eurasian watermilfoil
R Elodea canadensis (water weed)
Najus minor
Toothed water weed
R Not used ornamentally
Nasturtium officinale
Watercress
R Not used ornamentally
Nymphoides peltata
Yellow floatingheart
R Native Nuphar (yellow pond lily)and Nymphaea (waterlily)
Pastinaca sativa
Wild parsnip
R Not used ornamentally
Pennisetum alopecuroides
Chinese fountain grass
R  
Perilla frutescens
Beefsteak plant
R Monarda didyma (bee balm), Pycnanthemum muticum (mountain mint), Coleus, Occimum basilicum (basil)
Persicaria perfoliata (formerly Polygonum perfoliatum)
Mile-a-minute vine
R Not used ornamentally
Phalaris arundinacea
Reed canary grass
R Spartina pectinata 'Aureomarginata' (variegated prairie cordgrass)
Phellodendron amurense (excluding male cultivars)
Amur corktree
R Acer rubrum (red maple), Phellodendron amurense (male cvs.), Quercus alba (white oak)
Phellodendron japonica (excluding male cultivars)
Japanese corktree
R Acer rubrum (red maple), Phellodendron amurense (male cvs.), Quercus alba (white oak)
Phragmites australis
Common reed
R Erianthus ravennae (Plume grass)
Pistia stratiotes
Water lettuce
R No ornamental alternative
Poa compressa
Canada bluegrass
I Used in pastures and lawns, not used ornamentally
Poa pratensis
Kentucky bluegrass
I Used in pastures and lawns, not used ornamentally
Polygonum cuspidatum = P. japonicum
Japanese knotweed
R Actaea racemosa (black cohosh), Aruncus dioicus (goatsbeard), Polygonatum spp.(Solomon's seal), Smilacina racemosa (false Solomon's seal), Tricyrtis spp.(toad lily)
Polygonum perfoliatum
Asiatic tearthumb
R  
Polygonum sachalinense
Giant knotweed
R (see P. cuspidatum)
Populus alba
White poplar
P Tilia americana (American linden or basswood)
Portulaca oleracea
Purslane
R Aurinia saxatilis (basket-of-gold), selected Sedum spp. & cvs. (stonecrop)
Potamogeton crispus
Curlyleaf pondweed
R Not used ornamentally
Potentilla argentea
Silver cinquefoil
R Chrysogonum virginianum (green and gold)
Prunus mahaleb
Mahaleb cherry
P Crataegus spp. (hawthorn species), Prunus serotina (black cherry)
Pueraria montana =P. lobata
Kudzu vine
R Not used ornamentally
Pyrus calleryana
Callery pear
R Chionanthus virginicus (fringetree), Crataegus spp. (hawthorn species), Prunus serotina (black cherry)
Ranunculus ficaria
Lesser celendine
R Asarum canadense (wild ginger), Jeffersonia diphylla (twinleaf)  
Rhamnus cathartica
Common buckthorn
R Alnus rugosa (speckled alder), Carpinus caroliniana (American hornbeam), Corylus americana (American filbert), Thuja occidentalis (American arborvitae) and Thuja plicata (giant arborvitae)
Rhamnus frangula
Glossy buckthorn
R Alnus rugosa (speckled alder), Carpinus caroliniana (American hornbeam), Corylus americana (American filbert), Thuja occidentalis (American arborvitae) and Thuja plicata (giant arborvitae)
Robinia pseudoacacia (native to N. Am.; aggressive in our region)
Black locust
R wild type; E cultivars Catalpa speciosa (Northern catalpa), Gleditsia triacanthos (honeylocust)
Rorippa sylvestris
Creeping yellow-cress
R Aurinia saxatilis (basket-of-gold), selected Sedum ssp. & cvs. (stonecrop)
Rosa multiflora
Japanese rose
R (check rootstocks) Rosa spp. & cvs. (hardy shrub roses)
Rumex acetosella
Garden sorrel
R Beta vulgaris 'Bright Lights'(Swiss chard) Solenostemon scutellarioides (coleus)
Salvinia molesta and S.minima
Water fern
R Not used ornamentally
Saponaria officinalis
Bouncing bet
R Liatris spp. (blazing star), Monarda spp. (bee balm), Phlox spp. (phlox), Salvia spp. (sage), Thalictrum spp. (meadowrue), Veronica spp. (speedwell)
Setaria faberi
Japanese bristlegrass
R Not used ornamentally
Silene latifolia ssp. alba (Lychnis alba)
White campion
R  
Sonchus arvensis
Field sow thistle
R Coreopsis spp. (coreopsis); Helianthus spp. (sunflower)
Sorghum halapense
Johnson grass
R Not used ornamentally
Stachys balansae
No common name
R Failed plant evaluation. Stachys byzantina (lamb’s ears) or other Stachys spp.
Symphytum asperum
Prickly comfrey
R Mertensia virginica (bluebells)
Thalictrum buschianum
No common name
R Failed plant evaluation. Thalictrum aquilegiifolium (meadow rue) or T. flavum (yellow meadow rue)
Trapa natans
European water chestnut
R Not used ornamentally
Typha angustifolia
Narrow leaf cattail
R Typha latifolia
Ulmus pumila
Siberian elm
R Dutch-resistant cvs. of Ulmus americana (American elm)
Valeriana officinalis
Common valerian
R (See E. sphaerocephalus)
Verbascum thapsus
Flannel mullein
R Digitalis spp. (foxglove)
Veronica gentianoides
Gentian speedwell
R (failed plant evaluation), Veronicastrum virginicum (Culvers root), Veronica spicata (spike speedwell)
Viburnum opulus
European cranberrybush viburnum
R Viburnum dentatum cvs. (arrowwood viburnum), Viburnum trilobum (American cranberrybush viburnum)
Vinca minor
Common periwinkle
E, I Asarum spp. (ginger)
Vincetoxicum nigrum
Black swallowwort
R Matelea spp. (climbing milkweed)
Vincetoxicum rossicum
Swallowwort
R Matelea spp. (climbing milkweed)

Watch List

These species are not currently posing a serious invasive risk in the Chicago area, but may do so in the future, particularly as the climate changes. We are watching and monitoring for signs of invasiveness.

Scientific Name
Common Name
Plan

Alternatives

Akebia quinata W Clematis spp. (clematis), Parthenocissus quinquefolia (Virginia creeper), Passiflora incarnata (Passionflower)
Buddleja davidii W Aesculus parviflora (Bottlebrush buckeye), Amorpha canescens (leadplant), Sambucus nigra (elderberry)
Calamagrostis brachytricha W Schizachyrium scoparium (little bluestem), Sorghastrum nutans (Indian grass)
Elaeagnus angustifolia W Aesculus parviflora (bottlebrush buckeye), Aronia melanocarpa (black chokeberry), Corylus americana (American filbert), Ilex verticillata (winterberry holly), Aronia melanocarpa (chokeberry
Gypsophila paniculata W Euphorbia corollata (flowering spurge)
Houttuynia cordata W Alchemilla mollis (lady's mantle), Asarum spp. (ginger), Chrysogonum virginianum (green and gold)
Pennisetum alopecuroides W Schizachyrium scoparium (little bluestem), Sorghastrum nutans (Indian grass)
Quercus acutissima W Quercus shumardii (Shumard’s oak), Quercus coccinea (Scarlet oak), Quercus velutina (Black oak)
Ranunculus lingua W Caltha palustris (Marsh marigold)
Spiraea japonica W Clethra spp. (summersweet), Hydrangea spp. (hydrangea), native Spiraea (spirea), Ceanothus americanus (New Jersey tea)
Syringa reticulata W Clethra spp. (summersweet), Hydrangea spp. (hydrangea), Phyocarpus opulifolius (ninebark).
Tamarix ramosissima and other Tamarix spp. W Amelanchier spp. and cvs. (serviceberry), Calycanthus floridus (Carolina allspice), Diervilla spp. (bush honeysuckle), Lindera benzoin (spicebush), Viburnum dentatum (arrow-wood viburnum), Aesculus parviflora (bottlebrush buckeye)
Verbina bonariensis W Liatris spp. (blazing star), Monarda spp. (beebalm), Phlox spp. (phlox), Salvia spp. (sage), Thalictrum spp. (meadowrue), Veronica spp. (speedwell)
Wisteria sinensis W Clematis spp. (clematis), Parthenocissus quinquefolia (Virginia creeper), Passiflora incarnata (Passionflower), Wisteria frutescens (American wisteria)