As designers and horticulturists we go on at length about creating winter interest. Here in the Chicago area, our winters can be pretty long and bleak, so we need to be creative in the garden to keep from going completely round the bend. One of those tricks knowing gardeners do, is leave perennials up for the winter. They provide structure, seeds, and interesting silhouettes.
This is a fall blooming allium or ornamental onion
See how lovely this is in a fresh snowfall? The seeds feed the birds and the delicate dried petals give you a glimpse of the flower that bloomed months ago.