Commonly called African mask or elephant's ear plants, alocasia are ornamental perennials with leaves as large as elephant ears, hence the name. Depending on the variety, these tropical plants decorate an indoor or outdoor spot with large, showy and sometimes colorful foliage. Smaller varieties serve as accent plants that edge a walkway or patio. Protect these tropical plants from freezing winter temperatures so they remain healthy.
Alocasias thrive in warm and humid conditions and cannot survive cold temperatures. Dig the tropical plants out of the garden soil and bring them indoors before the first frost, advises University of Illinois Extension, d.
Potted alocasia plants are easier to bring indoors than those planted in the soil. However, the sudden change from outdoor environment to indoors with reduced light can shock the plant severely. Acclimatize the plant to lesser light one step at a time by placing the pot in a shadier spot for two weeks before moving it indoors, well before the first expected frost. Place the pot near an east- or north-facing window for plenty of indirect sunlight, and mist frequently to maintain humidity levels.
Mildly Cold Areas
Alocasia plants are frost-intolerant and some varieties cannot withstand temperatures below 45 degrees F. Elephant ear plants form tubers in the ground, so in mildly cold areas, it is safe to leave them outdoors, provided the soil is covered with a thick layer of mulch. Cut back the foliage before mulching. Wait for the leaves to turn brown or yellow before cutting them off, as the color change indicates the natural redirection of plant nutrients to the tuber.
Extreme Cold Areas
Bring tubers indoors in areas with harsh winters and hard freezes. In these areas, the alocasia's foliage turns yellow or brown well before the first frost because nutrients return to tubers underground. Let this process finish and wait until the foliage turns completely brown or yellow before cutting it off.
Wait until the first light frost in fall before digging the tubers out of the soil
advises University of Illinois Extension. Cut back stems to 5 or 6 inches and carefully dig the plant without damaging the tubers. Gently wash the soil off and allow the tubers to air dry. Separate smaller tubers that will form new plants the following year.
Place tubers in soda crates or milk containers packed with peat moss or sawdust and store in a dark area with consistent temperatures between 40 and 50 degrees F. Inspect the tubers frequently for rot, and discard immediately to prevent spread. Mist shriveled tubers so they are plump.
Remove the tubers from cold storage eight weeks before the outdoor soil is frost-free and plant them in large containers filled with good-quality potting soil. Place the containers near a warm window indoors or outdoors in a shaded spot first before moving them to direct sunlight.