Mulch Root Vegetables
Use hay or straw to mulch root vegetables such as carrots, parsnips, and rutabagas that will be stored in the ground for winter. Mulch will protect the ground from repeated freezing and thawing, which could push the roots right out of the soil.
Watch for Standing Water
Watch for standing water in perennial beds after long periods of rain. Water that collects on the surface during winter will freeze, damaging perennials or causing the crowns of some plants to rot. Dig shallow trenches to help drain excess water away and make a note to raise those beds in spring.
Once temperatures dip into the 30s, it's time prepare hybrid roses for winter weather. Prune canes to about 3 feet and spread protective organic mulch around the plant. I simply mound bark mulch around the base of the rose, high enough to cover the graft union (the swollen part of the stem near the ground). Hardy old-fashioned and shrub roses can be left as is for winter.
Dig Dahlia Tubers
Dahlias should be finished blooming by now. Cut remaining flowers from plants, and then wait for frost to kill the foliage. Cut dead foliage down to the soil line, dig the tubers, and store them for the winter in a cool, dry area in bags of slightly moist peat moss. Tubers can be separated now or left in clusters. I divide mine in spring, after new buds begin to swell.
Cut chrysanthemum stems back to ground level after they have stopped blooming. Dispose of stems and leaves by tossing them into the compost pile. Provide protection from winter cold with a 2- to 3-inch layer of organic mulch. When new shoots appear in the spring, dig the root mass and divide the plant, taking some roots with each new shoot.