Homegrown: Overwintering plants

Lisa Slattery, Linn County Master Gardener, sent the following about overwintering houseplants, tropicals and other flowers:

With this last week of fairly cold weather and our first hard frost I'm moving some of my favorite flowers and pots inside for winter. 

Ideally you should spray your plants that you plan to bring inside with soapy water or insecticidal soap starting in September along with applying a systemic pesticide.  That way you won't bring any pests into your house.  If you missed the window of opportunity for the systemic, go ahead with the spray.  I like to use my garage as the holding place before the pots or roots come inside. 

My tropical hibiscus plant is one that comes inside every winter.  They'll do well if placed in a bright, sunny window with a temperature of 65 to 70 degrees.  Keep the soil moist and don't fertilize.  The hibiscus will shed a lot of leaves at first but that will taper off.  In late winter (about March) cut back the hibiscus by about 1/3 and begin to fertilize it with a diluted fertilizer solution every two weeks.  Then when the outdoor temps have warmed, move the hibiscus outside to a shady location, gradually exposing it to longer periods of direct sun. 

Begonias are another of my favorites that come inside.  A few days after a killing frost dig up the tuberous roots and leave a small amount of soil around each tuber.  Cut off the stems to about one inch above the tubers.  Place these in a cool, dry area to cure for two to three weeks.  After curing, shake off the remaining soil and bury the tubers in dry peat moss, vermiculite or sawdust.  Store the tubers in an area with a temperature of 40 to 50 F but don't allow them to freeze.  I've also left begonias in pots with some success and then treated them like the tropical hibiscus. 

Callas also make the trip indoors.  These plants have rhizomes that must be dug up in the fall.  Again, after a killing frost, cut off the foliage 1 to 2 inches above the soil surface.  Carefully dig up the rhizomes and don't cut or injure them.  Dry the rhizomes in a warm, dry location for one to two weeks.  After drying, bury the rhizomes in vermiculite, sawdust or peat moss and store them in a cool (50 to 60 degrees F), dry location. 

Overwintering plants will save you money in the spring and give you a great sense of accomplishment.  It's also the best way to preserve special or favorite plants.