How Much Should I Trim Hibiscus After a Frost?

Pruning

• If frost damages a hibiscus, don't prune anything when more cold weather is on the way, according to the University of Florida IFAS Extension -- Osceola County Extension. Because brown leaves help to insulate plants from further frost damage, wait to prune until the spring, when new growth appears. When plants have sprouted, the amount to prune, the extension advises, is to just below damaged areas on branches, cutting into green, healthy wood. During the growing season, the extension recommends several light prunings to promote dense growth.

Bringing Indoors

• North Dakota State University Extension Services suggests allowing a hibiscus to get some frost damage and then placing it in a garage or another place where it can stay very cool -- about 54 degrees Fahrenheit -- for six to eight weeks. Prune it back hard and bring it it inside to a location that gets five to six hours of direct sunlight and temperatures no lower than 55 degrees Fahrenheit; although 68 to 75 degrees Fahrenheit is best. Provide just enough water to keep the media moist and fertilize when new growth appears. With this care, hibiscus often produces a few blooms during the winter.

Temperatures

• Although topical hibiscus plants can survive some frost damage, according to online reference The Tropical Hibiscus, the plants are native to sunny, warm and typically humid places. It is risky for them to be outside for more than a night or two of light freezes, and they can die from one hard freeze under 25 degrees Fahrenheit. To prevent any frost damage, bring the plants indoors before nighttime temperatures regularly drop below 40 to 45 Fahrenheit. If plants look spent after four or five years, it means they have lived their natural lifespans.

Hardy Vs. Tropical

• Frequently retail stores and garden centers do not indicate whether a hibiscus is tropical or hardy. According to The Tropical Hibiscus, a hibiscus is tropical if its flowers are salmon, peach, orange or yellow, or if they are double-flowered or have more than one color in either bands or in spots. Hardy hibiscus plants have dull medium-green, heart-shaped leaves and dinner-plate sized white, pink or red flowers. If you buy inexpensive plants in fall, keep the plants in pots and protect them from winter cold. Plant outdoors, if desired, in spring.