If you store any potted perennials or shrubs that aren't hardy in your region in a cold but sheltered place for the winter, you may wonder when exactly it is safe to move them back outdoors in spring.
Specific timing will vary depending on the hardiness of the plant and how that compares with the hardiness zone in which you garden. A safe general approach, though, is to move the hardiest perennials in storage—those rated just one or two zones warmer than your locale—back outdoors once your neighborhood's nighttime air temperatures remain consistently above freezing. For more tender or tropical perennials, hold off on bringing them outdoors until night temperatures stay above 50˚F.
With any perennial that's been in storage, make its move outdoors a gradual one. Even sun lovers should sit in a shaded garden space for a while before moving into full sun. Put them in shade for a few days, then part shade for a few days, and then finally into their final sunny position. This will prevent the plants from being shocked or scorched.
Image: "Hotel Baron thermometer" by Bernard Gagnon - Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons.
Learn more tips on growing tender perennials regardless of location, plus much more, in Kristin Green's Plantiful.
Growing tender plants too much fuss for you? Get bone-hardy plant recommendations, streamlined gardening calendars and simple but stunning planting plans in The Know Maintenance Perennial Garden by Roy Diblik.
Learn to use a home greenhouse as a winter plant storage space and much more with The Greenhouse Gardener's Manual by Roger Marshall.