Late October through early November is the perfect time to prepare your perennial gardens for winter.  It is the best time to spruce up your garden by trimming back all of your perennials to a few inches above the ground.  Ornamental grasses can also be cut back but most times provide nice interest in the garden throughout the winter months.  Most people prefer to leave that chore for early spring instead.  Fall is also a great time to plant bulbs for their pop of color to be enjoyed in early spring before the perennial season.