Dusty Miller is the common name for several varieties of a herbaceous perennial with silver leaves. The plant is a tender perennial that is native to Mediterranean climates; it is drought tolerant and does well in full sun. In the United States, Dusty Miller is usually treated as an annual in zones 3 through 8, but can be overwintered in zones 5 through 8 with proper care. Dusty Miller does not overwinter well outdoors in areas of zone 10 that experience very wet winters; although not in danger from frost, the plant may die from root rot and should be brought indoors for the winter.
Trim the Dusty Miller to about 4 inches in height. This can be done after the first frost, if you'd like to leave the plants until the annuals in the garden have died off.
Mulch the Dusty Miller with 6 to 8 inches of grass clippings, leaves, pine needles, peat mulch, and/or straw. Top with a layer of hay or straw, and secure the mulch with garden netting or evergreen boughs.
Remove the hay and mulch in the spring after the risk of frost has passed.
Trim the Dusty Miller to about 6 inches in height.
Dig up the plant, making sure not to damage the root ball.
Pot the plant in fresh potting soil. Use a pot about twice the diameter of the root ball.
Wash the leaves with an insecticidal soap, to prevent outdoor bugs hitchhiking a ride indoors where they can infest your houseplants.
Select a sunny location indoors for the pot.
Water the plant every week to 10 days during the winter. Do not over-water.
Move the pot outdoors for a few hours a day to re-acclimate the plant to the outdoors once the daytime temperature in the spring is above freezing. When the risk of nighttime frost has passed, you can replant the Dusty Miller in the garden.