Incorporating perennials in your fall landscaping is an easy way to enjoy a fuller, longer blooming season for your garden, without the hassle of replanting flowers every year. Ideally, you should visit a garden center and take a peek at what is blooming in the fall months. However, not every garden center will have a full array of grown fall-blooming perennials. If you have a specific flower or plant in mind for your landscape in the fall, it behooves you to do some pre-planning and buy them in the spring or summer when they may be more readily available at the garden center, then wait until fall to transplant them into your yard. Keep in mind when the ground freezes solid in your region, as you should plant your flowers at least six weeks before the ground freezes.