Divide Iris and Daylilies
Lift iris clumps with a shovel and break them apart. Save the plumpest, firmest rhizomes, and discard the old, leafless ones. Trim the leaves to about 6 inches long. Let the rhizomes air dry overnight before planting. Daylily clumps are so dense you'll need to slice through them with a shovel or spade. Separate them into smaller clumps, leaving at least three plants per clump. Trim leaves to about 6 inches long and replant.
Dig overgrown peony clumps with a shovel and cut them in half. Handle with care so the "eyes" or buds at the base of the plants aren't damaged. Plant so the eyes are 1-1/2 to 2 inches below the soil surface. If planted too deeply, they won't flower.
As you empty annual beds this fall, till in any plants that aren't diseased to return nutrients to the soil. Spread compost, even if it's not well decomposed yet. It will protect the soil over the winter and break down by spring planting time.
Plant Cover Crops
Crimson clover, Austrian winter peas, and grains such as wheat, oats, and rye will boost the fertility and organic matter of your soil if you plant them now, let them grow all winter, and turn them under in spring. As an added bonus, winter cover crops host many beneficial insects.
Plant More Pansies
It's not too late to plant more pansies. Replace spent summer annuals with these colorful flowers to complement fall decorations. Plant some in pots, too, so you can move them around wherever you want spots of color; you can move them into a protected area if a hard freeze threatens.