Landscaping a bank
Thanks for writing. There are many good choices for a sunny slope in Wisconsin. If you want an evergreen, creeping juniper is probably your best bet. It's very heat and drought tolerant. The one thing about it is that you'd not want to walk through it, so don't plant it right at the bottom of the hill next to the school property. Low-Gro sumac is another good choice; it's a fast-growing dwarf shrub.
If you'd like to include some perennials, then daylilies are always a good bet because they're so low-maintenance. If you want perennials that spread very fast, consider mint, gooseneck loosestrife, or ribbongrass.
Learn more about these and other great plants in our Plant Encyclopedia: http://www.bhg.com/gardening/plant-dictionary/
---Justin, Senior Garden Editor, BHG.com