Ask Mr. Smarty Plants

Trilliums prefer to be on the floor of mature, hardwood, primarily deciduous forests in some amount of shade. If they are now in full sun throughout the day, they may very well expire. However, if they're still getting dappled shade from other neighboring trees or shrubs, especially during the hottest part of the day, they may pull through. Hostas might work, but it's hard to know for sure.

What would probably be better in the long run would be to plant native deciduous trees or shrubs near them, tall enough to provide at least dappled shade from the outset. That way, the woody plants' leaves will provide the kind of shade with which the trilliums have evolved and will also enrich the soil when they drop in the fall, contributing to the kind of woodland soil to which trilliums are accustomed.

The Illinois Plant Information Network notes that Trillium grandiflorum, the best known white trillium and one native to your state, is often found growing among the following trees and shrubs:

American Beech (Fagus grandifolia)
Northern Red Oak (Quercus rubra)
Sugar Maple (Acer saccharum)
White Ash (Fraxinus americana)
American Basswood (Tilia americana)

Planting young specimens of one or two of those trees, tall enough to provide shade during the day, is one idea. Our Native Plant Database can help you learn about the many other kinds of deciduous trees and shrubs native to your area, and our National Suppliers Directory can help you locate plants when it's time to purchase.

If you do decide to attempt transplanting, it's best to wait until the plants go dormant and then get as much of the root and surrounding soil as possible. A local chapter of your state's native plant society or of the Wild Ones may be able to give you more information on how best to do this, if at all. Many native plant societies do plant rescues and they may well have had experience salvaging trilliums in your area.