It is our responsibility as citizens, but especially as practitioners in the fields of horticulture and botanical sciences, to be good stewards of the land and ensure that what we are growing in our backyards and at the Chicago Botanic Garden will not contribute to problems in the future. That is why the Garden recently replaced the callery pears at the entrance to the Visitor Center.
In addition to the callery pear, the Garden also removed winged euonymus (Euonymus alatus) and tamarisk (Tamarix spp.).
One threat to our natural world is invasive plants. While many of these plants may on the surface appear to be attractive additions to the landscape, they can force out native species. Short of complete destruction of a natural area, I cannot think of anything more unsightly than a natural area that has been completely consumed by an invasive species to the point that it is no longer recognizable and holds very little biodiversity.
The list of invasive plants and potentially invasive plants is not set in stone; it is an evolving list and one that will continue to change as our climate changes. The callery pear (Pyrus calleryana) was not on the invasive species lists for our region a decade ago, but today it is in Illinois, along with Alabama, Georgia, South Carolina, and Tennessee. Most are familiar with the cultivar ‘Bradford’, but there are several others, including ‘Aristocrat’, ‘Autumn Blaze’, and ‘Cleveland Select’.
This spring we replaced all of the Pyrus calleryana ‘Autumn Blaze’ at the front entrance of the Visitor Center with the non-invasive American yellowwood (Cladrastis kentukea). As a result, the front entrance is noticeably more open in appearance, and the low canopy and refreshing shade that existed in years past is now gone; it will return as the plantings grow.
Although both of these species are medium-sized deciduous trees with white flowers, the yellowwood has different ornamental characteristics. The callery pear flowers in the early spring, while the yellowwood flowers in late spring to early summer. The callery pear has unrivaled fall color in shades of red, orange, and yellow, while the yellowwood is one of the best for yellow fall color.
Why is the callery pear called an invasive?
This pear has abundant seeds that can be carried by birds to natural areas. Plants can then become established, thus displacing native species. As land stewards, the Garden is very mindful of prohibiting and eliminating any plants known to be invasive in our region.
I have no doubt that some of these recently removed invasive plants were favorites among Garden visitors, our staff included. But sometimes what we like isn’t always good for us, or good for the environment.
I encourage you to review and continue to consult invasive species lists, including on the invasive.org website, and do your part by removing invasive species from your garden and resist purchasing and adding more. There are so many benign, beautiful options available to gardeners, and the Garden, along with numerous other organizations, has done the work for you by listing alternatives for the invasive plants that we feel we cannot live without. View a list of our recommended alternatives to invasive plant species here.
Each of us can play an important role in preserving the natural landscapes for future generations.
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