Greetings Carol:
I'm not familiar with American silverberry as this species is not native to Illinois. Having said that, I would probably recommend doing a little background work on your end by starting with the USDA Plants Database:
http://plants.usda.gov/java/profile?symbol=ELCO
Seeing that I am a staunch advocate of planting locally adapted native species, I'm very hesitant to recommend the planting of unfamiliar plant species without knowing more about the ecology of this plant. I mention this fact because American silverberry is in the same genus as Russian olive and autumn olive -- two notoriously invasive and problematic tree/shrub species here in Illinois and the Midwest.
Without additional research, my initial gut reaction tells me to avoid planting this species here in Illinois.
