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Plant Science and Conservation

• Invasive Plant Science
   and Policy
• What is an Invasive
   Plant?
• Invasive Plants in the
   Chicago Region
• Chicago Botanic Garden
   Invasive Plants Policy
• What can you do?

Plant Science — Conservation

Invasive Plants in the Chicago Region

Trees

 

Plants with a dash under the "alternatives" column are not commonly used ornamentally. You can find more information on alternatives at Illinois' Best Plants or www.bestplants.org.

TREES
Species	Common Name	Status	Alternatives
Acer ginnala	Amur maple	P	Acer rubrum (red maple), Quercus alba (white oak)
Acer platanoides	Norway maple	R species E cultivars	Acer x freemanii 'Marmo' (Marmo maple), Acer miyabei (Miyabe maple), Acer rubrum (red maple), Quercus alba (white oak)
Ailanthus altissima	Tree-of-heaven	R	Fraxinus spp. (ash species)
Alnus glutinosa	European black alder	P species E cultivars	Celtis laevigata (sugarberry), Celtis occidentalis (common hackberry), Nyssa sylvatica (black tupelo)
Malus spp. (crabapple)	Crabapple	E	Crataegus spp. (hawnthorn species), Prunus serotina (black cherry)
Morus alba	Mulberry	P	Crataegus spp. (hawthorn species), Prunus serotina (black cherry)
Phellodendron amurense (except male cultivars)	Amur corktree	R	Acer rubrum (red maple), Phellodendron amurense (male cvs.), Quercus alba (white oak)
Populus alba	White poplar	P	Betula nigra (river birch), Catalpa speciosa (Northern catalpa), Platanus occidentalis (American sycamore)
Prunus mahaleb	Mahaleb cherry	P	Crataegus spp. (hawthorn species), Prunus serotina (black cherry)
Pyrus calleryana	Callery ornamental pear	W	Chionanthus virginicus (fringetree), Crataegus spp. (hawthorn species), Prunus serotina (black cherry)
Robinia pseudoacacia	Black locust	R species E cultivars	Catalpa speciosa (Northern catalpa), Gleditsia triacanthos (honeylocust)
Ulmus pumila	Siberian elm	R	Dutch-resistant cvs. of Ulmus americana (American elm)

Chicago Botanic Garden Conservation Science Department 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 list (taxa not posing a serious invasive risk in the Chicago area currently, but may do so in the future).