On May 9, 2007 the City Council passed the Invasive Species Ordinance
that made it unlawful to possess certain invasive plant and animal species. At
the time the plants on the list were mostly aquatic plants, but this
year the list was updated to include land-based invasive plants. The
updated Invasive Species Ordinance now makes it illegal to; "import,
sell, transport, own, keep, release, introduce, or otherwise possess in
the City of Chicago," the following plants of March 2009:
Chocolate Vine, Elegans Porcelain Berry Vine, Wild Chervil, Oriental Bittersweet, Japanese Hops, Lyme Grass, Privet, Amur Silver Grass, Princess tree, AmurCorktree, Japanese Corktree, Japanese knotweed, Sawtooth Oak, Lesser Celadine.
Nothing on the list growing in my garden, how about yours? Will you
remove any these plants if they are currently found in your garden?
Besides Chocolate Vine (Akebia quinata ) nothing on the list that I
would go out of my way to buy or grow. The list of plants is rather
boring, if you ask me. The land-based plants chosen were selected
because they are in trade but not yet widespread. I guess the idea here
is to deal with them now, rather than in the future when they could be
While researching a weed in my garden I came across the City of Chicago Land-based Invasive Plant Brochure (pdf)
which is where the information above came from. I discovered that I'm
harboring at least three species of invasive plants in my own garden.
While not regulated by the City, the three I'm growing are discouraged.
My three offenses from this list are; the orange daylily, Perennial Sowthistle and I believe now, Canada Thistle. Although none of the recently blooming weeds in my garden were on the list.
season is the first year Canada Thistle was spotted growing in my
garden and I've let it grow partially because of laziness, but mostly
because of curiosity of what the blooms would look like and what it
would attract in the garden. One day while photographing some bees and
beetles that were visiting the lavender colored blooms I discovered
that the flower is sweetly scented. Now that I know just how noxious a
weed Canada Thistle is I don't think I'm going to let it go to seed or spread in
If you have plants growing in your garden and you
want to know if they are invasive or not, look through the brochure linked
above. It has 16 pages of good information and non-invasive plant
suggestions to replace the invasive plants now banned in Chicago along
with 26 common invasive plants you should avoid.
Update: There's also a list of invasive plants for the Chicago Region put together by the Chicago Botanic Garden.