The Greening Schools web site includes a "Groundskeeping/Landscaping" category in its section on greening your building. See
http://www.greeningschools.org/resources/view_cat_admin.cfm?id=11. The information on rain gardens may be helpful. Rain gardens employ native plants to gradually filter water and prevent pollution from stormwater runoff. This section of the Greening Schools web site also includes information on funding opportunities related to school gardens.
You may want to contact the Southern Chapter of the Illinois Native Plants Society for guidance. See http://www.inhs.uiuc.edu/inps/index.html. The contact for the Southern Chapter is Alice DeJarnett. She can be reached at 618-351-8106 or alicedel@yahoo.com.
Ken Robertson, a plant systematist for the Illinois Natural History Survey, has a nice web site on the tallgrass prairie in Illinois, which you may find helpful in preparing your unit. See http://www.inhs.uiuc.edu/~kenr/tallgrass.html. He also has a page entitled "Links for Using Native Plants in the Landscape" at http://www.inhs.uiuc.edu/~kenr/prairienativelinks.html. The Natural History Survey also has educational materials available at http://www.inhs.uiuc.edu/chf/outreach/eduresources/edupublications.html.
The Illinois Department of Natural Resources has posters and other educational materials available. In particular, see Wild about Plants at http://www.dnr.state.il.us/lands/education/classrm/plants.htm. They also have posters for several different regions of the state. An order form for these is available at http://www.dnr.state.il.us/lands/education/CLASSRM/edmats02.htm.
You may want to consider having an expert on native plants speak to your science club. Check out the Survey's speakers bureau at http://www.inhs.uiuc.edu/chf/outreach/speakersbureau/speakintro.html. Your local U of I extension office may also have someone you can speak with about this topic or who can visit the club as a speaker. The U of I Extension southern regional office is located in Mt. Vernon. You can contact the office at (618) 242-9474. Their website is at http://web.extension.uiuc.edu/cie2/offices/indexcenter.cfm?OID=226&CFID=73349&CFTOKEN=96991013.
The University Museum of Southern Illinois University has teachers' resource kits available for loan, including a kit on wildflowers of southern Illinois. See http://www.museum.siu.edu/kits.html for contact information. Also check out the web page on "Botany in the Natural Areas of Southern Illinois" on the Southern Illinois University Plant Biology Department web site (http://www.science.siu.edu/plant-biology/Information/Natural.html).
The Illinois Plant Information Network has lists of species available by county. See http://www.fs.fed.us/ne/delaware/ilpin/ilpin.html#Background.
Fermilab maintains a database of prairie plants with photos at http://eddata.fnal.gov/lasso/plant_search/search_kids.html. There is also a gallery of Southern Illinois Wildflowers at http://toms_place_2.tripod.com/SIwildflowers.htm.
A section of the U.S. EPA web site is devoted to information on native landscaping. See http://www.epa.gov/glnpo/greenacres/index.html.
The University of Illinois Cooperative Extension office publishes Native Plants in the Home Landscape for the Upper Midwest (https://webstore.aces.uiuc.edu/shopsite/C1381.html). It costs $20 but you may be able to borrow a copy of this through your school or local public library.
If your science club develops its own native plant garden on the school grounds, consider having it certified via the National Wildlife Federation Schoolyard Habitats program. See http://www.nwf.org/schoolyardhabitats/ for more information.
Finally, your local library may have some general information about gardening with native plants and flowers. Some titles, which you should be able to borrow through your local library, include:
Gardening with native wild flowers / Samuel B Jones; Leonard E Foote 1999, ©1990 (Pbk. ed.)
Portland, Or. Timber Press, ; ISBN 0881923818
The wild lawn handbook : alternatives to the traditional front lawn / Stevie Daniels, 1995.
New York, NY Macmillan USA, ; ISBN 0025294458
Natural landscaping : designing with native plant communities / John Diekelmann; Robert Schuster, 2002.(2nd ed.)
Madison, Wis. University of Wisconsin Press, ; ISBN 0299173240
The landscaping revolution : garden with mother nature, not against her / Andy Wasowski; Sally Wasowski, 2000.
Lincolnwood, Ill. Contemporary Books, ; ISBN 0809226650
Easy care native plants : a guide to selecting and using beautiful American flowers, shrubs, and trees in gardens and landscapes / Patricia A. Taylor, 1996 (1st ed.)
New York H. Holt, ; ISBN 0805038612 (alk. paper)
The native plant primer / Carole Ottesen, 1995 (1st ed.)
New York Harmony Books, ; ISBN 0517592150
Grow wild! : low-maintenance, sure-success, distinctive gardening with native plants / Lorraine Johnson; Andrew Leyerle, 1998.
Golden, Colo. Fulcrum Pub., ; ISBN 1555913962 (hardcover)
On the wild side : experiments in new naturalism / Keith Wiley, 2004.
Portland, OR Timber Press, ; ISBN 0881926361 (hardback)
Native landscaping for wildlife and people : how to use native midwestern plants to beautify your property and benefit wildlife / Dave Tylka, 2002.
Jefferson City, Mo. Missouri Dept. of Conservation, ; ISBN 1887247343
Eco-gardens / Lori Kinstad Pupeza, 2002.
Minneapolis, Minn. Abdo Pub. Co., ; ISBN 1577650336
Explains how to design and plant an ecologically sound garden by using native plants, which are adapted to the heat and water which nature supplies, and which will provide an environment for native animals and insects.
