I know nothing about cold climates, Jamie, but if you want something bushy that blooms a lot, you probably should concentrate on rose shrubs. The landscape roses like the Meidilands are good rebloomers, and most of them are hardy to zone 4. They come in a variety of colors and heights and they're virtually carefree. I never deadhead mine and they still keep blooming constantly. I have Sevillana and Cherry Meidiland, which are easy to keep within bounds, somewhere between 3-4 feet tall and about 3 feet wide. I also have Fuchsia Meidiland, which is much shorter (2 feet) and more like a ground cover because it spreads out horizontally rather than getting taller.
Here are two pages of roses with "Meidiland" in their names. If any of the colors appeal to you, click on the names and you'll find more photos, comments by other gardeners, and places to buy them.
http://www.helpmefind.com/rose...
I'm sure there are many more rose shrubs that would grow nicely for you in your zone, but I'll leave those recommendations up to Vicky or Toni or someone else in a colder zone.
