The state flower of Hawaii, hibiscus bears the largest blossoms that can be produced by an indoor plant. Some measure more than 8 in/20 cm across, and all feature crepe-paper-textured petals that flare around a prominent yellow stamen. Individual blossoms last only 2 to 3 days, but well-adjusted plants often bloom intermittently from late spring to late fall.
Hibiscus plants need warmth, so they are best grown near a south or west window. If possible, move them outdoors in summer to a place where they will receive partial sun. Be sure to bring them back indoors before night temperatures fall to 50–55°F/10–13°C. You can control the size of your hibiscus by pruning the plant lightly in early summer and more aggressively in Autumn. Hibiscus blooms form on the tips of new branches, which emerge from just below where older branches are tipped back.
Hibiscus plant profile
Light: Bright, including some direct sun.
Temperature: Warm (65–85°F/18–29°C).
Fertilizer: From spring through summer, feed every 2 weeks with a balanced liquid fertilizer. In winter, feed monthly. Alternatively, fertilize twice yearly with a high-nitrogen, controlled-release fertilizer. Special hibiscus fertilizer has an analysis of 18-5-23.
Water: In warm weather, water as often as needed to keep the soil lightly moist at all times. In winter, allow the soil to dry to within 1 in/2.5 cm of the surface between waterings.
Soil: A light-textured potting soil that contains perlite and peat.
Repotting: Annually in fall, prune back stems by one-third, and also trim off about one-fourth of roots before repotting.
Longevity: 5 to 10 years for most hybrids.
Propagation: Many hibiscuses can be propagated by rooting 6 in/ 15 cm-long stem tip cuttings. Many hibiscuses are grafted onto special rootstocks, so rooted cuttings may not show the vigor of their parent.
Selections: There are dozens of named varieties in shades of pink, blue, red, and yellow, with many colors.
- Dragon’s Breath features bold red, 8 in/20 cm blossoms with white swirls in the centers.
- The Path is bold yellow with magenta centers.
Display tips: Grow plants in pots that can be slipped inside larger planters equipped with wheels so they are easy to move outdoors in summer.
Problems and troubleshooting
Buds drop off soon after they form.
CAUSE: Environmental stress or weak cultivar.
REMEDY: Any type of stress that strikes when buds are swelling can cause plants to give up their will to bloom. Water attentively after bud appear and avoid moving bud-bearing plants unnecessarily. Varieties that produce large, double flowers are more likely to drop buds than those that bear single blossoms.
Leaves turn yellow and drop off.
CAUSE: Normal in fall, but excessive leaf drop can be caused by a sudden reduction in light.
REMEDY: Plants that are grown outdoors in summer — and even those kept indoors year-round — often shed some of their leaves when returned to comparatively dim indoor rooms. To keep shedding to a minimum, gradually accustom plants to less light.
Leaves appear parched, with pale yellow specks.
CAUSE: Spider mites.
REMEDY: Prevent this problem by washing off leaf undersides with plenty of water once a month. See page 276 for details on identifying this pest. If spider mites are present, isolate the plant, prune off badly infested branches, and spray plant daily with water. Use insecticidal soap if the problem persists.
Leaves small and misshapen.
CAUSE: Too much phosphorous in fertilizer.
REMEDY: Some hibiscuses are sensitive to high amounts of phosphorous (the middle number in a fertilizer’s analysis). Leach pots as described on page 263 and switch to a low-phosphorous fertilizer.