A Leggy Hibiscus Problem

Hibiscus Varieties

• There are numerous species of hibiscus, with a range of cultural requirements and levels of hardiness, all with large brightly colored, five-petaled flowers that feature pronounced, bristly stamens. The tropical hibiscus (Hibiscus rosa-sinensis) is suitable for U.S. Department of Agriculture plant hardiness zones 9 through 11 and wintered indoors elsewhere. Varieties that can survive some cold include rose mallow (Hibiscus moscheutos), hardy from USDA zones 4 through 10 depending on cultivar; rose of Sharon (Hibiscus syriacus), perennial from USDA zones 5 through 8; and scarlet rose mallow (Hibiscus coccineus), also called Texas star, which is winter hardy in zones 6 through 9.

Legginess

• Hibiscus usually becomes leggy because it is striving to reach more sun or hasn't been pruned regularly -- often a combination of the two. A "leggy" plant is not only tall, and in some cases spindly, but has sparse growth or is bare at the base. Upper growth shades out the base of the plant, leaving the lower part of the stems exposed. Aside from exposed stems, the other problem a leggy hibiscus has is form. Usually upright and vase-shaped, the weight of the large flowers and foliage on overly tall, thin stems can cause stems to arch over, opening the shrub up in the center with the tops falling over onto surrounding plants.

Sun Seekers

• Planting hibscus of any variety where it receives full sun helps to keep growth compact. All varieties of hibiscus thrive with a minimum of six hours of direct sunlight each day, though some can bloom well with as little as two to three hours of direct sunlight, as long as it hits the plant between 10 a.m. and 6 p.m, when the light is most intense. Consider moving an outdoor hibiscus while it is dormant in the late winter to early spring to a sunnier spot if the plant isn't blooming well and foliage is sparse. Indoor hibiscus needs the sunniest spot in the house to avoid legginess.

Proper Pruning

• Once you've cut a leggy hibiscus down to a bud near the base at the beginning of the season, there are a few other pruning techniques that can keep it full and lush through fall. Cut all the branches on your hibiscus back by 6 inches when the plant has put on 1 foot of growth. Multiple stems grow from each cut for a fuller plant with more foliage low on the plant. Once those stems grow another 12 to 18 inches, pinching out just the bud at the end of the stem prompts more branching without losing height. Once a hibiscus completes its late-summer flowering, gardeners in areas with long growing seasons can cut the plant back by half again, both to discourage late-season legginess and to prompt a new round of fall flowers. Wait to cut down any later growth until spring, to avoid winter damage to new growth.