Garden News: Some holiday plants can keep long after holidays Garden News: Some holiday plants can keep long after holidays Advocate news services Feb. 01, 2014 Comments While the holidays are over, that doesn’t mean your holidays plants are, too. If you have holiday plants still living in your home, you may be able to keep some of them going for years. Amaryllis bulbs are forced to bloom in pots, generally in December. After the flowers have died, you’re left with strappy leaves. LSU AgCenter horticulturist Allen Owings says you should keep the plant inside and continue to provide it with plenty of sun and proper watering until March or April. Then plant it in the garden where it will bloom in April for many years. Amaryllis in the landscape can be left alone for several years. Mulching will help reduce weeds and conserve moisture, and a thicker layer during winter will help protect from freeze damage. Holiday cactuses will produce gorgeous flowers year after year with proper care. LSU AgCenter horticulturist Dan Gill says you may keep plants indoors or move them outside for the summer. Outside plants can receive some morning sun, but they’re better kept in shade for most of the day. Move them indoors in fall when the buds are about an eighth of an inch long. Excessive watering can lead to root rot, so use loose, fast-draining potting soil rich in organic matter. These plants prefer to be potbound, so repot only if they are no longer stable. If you purchased a live Christmas tree, you can plant it outside now. Be sure you choose a sunny spot with enough room for the tree to grow to maturity. The Norfolk Island pine, however, is not hardy and will freeze. You can keep it as a houseplant near a sunny window and move it outside during summer. Another popular Christmas plant is rosemary that has been pruned into a tree shape. This winter-hardy herb can be left in the pot or planted in the ground. Reader question Gerald wrote that leaves on his mandevilla turned brown after the freeze. He wants to know if the plant will recover and produce new leaves and flowers. Dan Gill says mandevilla vines are very sensitive to cold and are generally killed by temperatures in the mid-20s or below. You would not expect them to sprout and grow in spring. But wait until May to be sure. Got a gardening question? Write to GardenNews@agcenter.lsu.edu.