Trim dead foliage from dahlias. Many gardeners leave them in the ground year after year. This process results in bushy, large plants as the tubers multiply over time. Commercial dahlia growers in western Washington choose to lift them, label the tubers with variety, and store them through winter in damp soil, vermiculite, or peat moss before dividing them. Don't neglect the lawn.
Rake leaves off, and keep the lawn mowed as needed.
Pick up any fallen branches after storms and keep the lawn raked. Don't walk on frozen turf. Winterizing roses isn't difficult. The main problem we have in western Washington is temperature variability. Nights with sub-freezing temperatures can become days with temperatures in the 50s, which encourage rose sap to rise and growth to resume.