At the end of the growing season, it is cleanup time. You should eliminate plant debris where pests can lurk over the winter. The compost pile is a better place for brown flower stems, frozen impatiens plants, dead leaves, cornstalks, and weeds.
But don't throw away things that are beautiful. Hosta leaves turn golden, just like autumn leaves, and you may as well enjoy them that way before they turn brown and you clean them up. Throw any disease-infested plant parts into the trash; do not compost them. When the garden is clean, you can mulch it for easier digging next spring.
Mow down old flower stalks in late fall to clean up a flower garden with ease. Before mowing anything but grass with your mower, make sure it has a safety feature that will prevent debris from being thrown out at you. Using a suitable lawn mower can save you plenty of time compared with cutting back the flower stalks by hand. If you allow the old stems to scatter around the garden, instead of bagging them, you may find an abundance of self-sown seedlings arising in the springtime.