Hibiscus plants rotate through an annual cycle. These plants mature within 2 to 3 years, reaching a mature height of 2 to 8 feet and returning to roughly the same height every year. Planting seeds in early spring can yield flowers the same year.
Plant hibiscus seeds indoors about 12 weeks before the last spring frost. Before sowing, soak seeds in warm water. If you’re planting outdoors, it’s possible to sow hibiscus seeds in fall or after the last predicted frost date. Some hibiscus enthusiasts enjoy creating new varieties by blending pollen from different varieties. Pollination occurs when pollen falls to a plant’s stigma pads and connects with the plant’s ovary. The ovary of a hibiscus will swell after connecting with pollen, creating a pod within 6 to 14 weeks. Seeds may be harvested and planted if desired. Seedlings will bloom within 6 to 24 months after planting.
Replant hibiscus plants, if desired, during February and March, before plants enter their annual growth stage. For optimum replanting, loosen the plant's root system and trim away dark-brown or soft roots. For replanting, choose a pot one size larger than the current pot.
The growth period for a hibiscus plant is March to October. During this time, plants get ready for intense flowering and can be prepared with water-soluble fertilizer formulas. Low-phosphorus fertilizers boost flower production, and high-phosphorus fertilizers boost leaf production.
The best time for pruning hibiscus is August to October, although it’s also possible to prune during spring. Because hibiscus produce flowers on new shoots, pruning can help encourage blossom production. Trim enough to leave 3 or 4 primary branches, then trim these by one-third for conservative care that won’t threaten the plant’s growth.
You'll need to provide appropriate care as the hibiscus plant grows in later stages. During colder seasons, tend your hibiscus plant by covering its base with a layer of straw, mulch or blankets. Regularly mist indoor hibiscus plants with water, or place near a humidifier. Provide additional light in winter with fluorescent bulbs.
As your hibiscus proceeds through various stages, it may face threats from external sources. Eliminate ants and aphids from your hibiscus plant by spraying the underside of leaves with water. Spider mites can create yellow, bumpy patches on hibiscus plant leaves, or create small webs; eliminate these by applying miticide to the leaves.