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 |
R | Physocarpus opulifolius (ninebark), Ribes odoratum (clove currant) |
|
Berberis koreana x B. thunbergii (incl. 'Tara' cv.) |
R | Physocarpus opulifolius (ninebark), Ribes odoratum (clove currant) |
|
Berberis thunbergii |
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) |