Hibiscus tiliaceus – Sea Hibiscus (Hau)
Hibiscus tiliaceus, known as sea hibiscus or hau, is a sprawling tropical tree or shrub of coastal areas from the mallow family (Malvaceae). It is valued for its heart-shaped leaves and color-changing flowers, and for centuries it has provided Pacific peoples with fibers and lightweight wood.
Synonyms and Nomenclature
The species was described by Linnaeus (1753); the Kew POWO database accepts the name Hibiscus tiliaceus L., while some authors treat the segregated genus Talipariti as an alternative. Synonyms include:
- Talipariti tiliaceum (L.) Fryxell
- Pariti tiliaceum (L.) A.Juss.
- Parita tiliaceus (L.) Scop.
- Hibiscus tiliifolius Salisb.
- Pariti tiliifolium Nakai
In English, the plant is called “sea hibiscus,” “beach hibiscus,” and “coast cottonwood,” and in Pacific languages, among others, hau (Hawaiian), vau, fau, and purau; the Polish name is ketmia lipowata. The recurrence of these names in many languages reflects the plant’s dispersal by Austronesian sailors.
Origin and Appearance
This is a pantropical species growing on tropical and subtropical coastal areas of the Indian and Pacific Oceans—from tropical Africa and South Asia to northern Australia and nearly all Pacific islands (including Hawaii). It grows from sea level up to about 800 m, on beaches, riverbanks, and mangrove edges.
It is a sprawling, evergreen tree or shrub 4–10 m tall, with branches often arching and rooting where they touch the ground, forming dense thickets. The leaves are large, heart-shaped, dark green above, pale and hairy beneath. The flowers (5–8 cm) last one day: they open in the morning bright yellow with a dark maroon center, turn orange during the day, then red before falling.
Frost Resistance and Cultivation
Hibiscus tiliaceus is a strictly tropical, frost-sensitive plant (USDA zones 10–11). However, it is exceptionally tolerant of coastal conditions: it withstands salinity, salt spray, and even periodic flooding, and grows on coral and limestone sands (pH around 5–8.5). In temperate climates, it is grown in pots, in warmth and full sun, protected from frost – in Poland under covers or as a houseplant.
Cultivation from seeds
The seeds have a hard, impermeable shell, so it is worth scarifying or soaking them in warm water for 12–24 hours before sowing – this speeds up and evens out germination. Sow them in warm (25–30°C), moist, well-draining substrate; seedlings usually appear within 1–4 weeks. This is an easy cultivation; the plant also roots very well from cuttings.
Uses
This is a classic "travel plant" of the Pacific – its bast provided strong fiber for cords, ropes, and nets, and the light wood was used to build parts of canoes with floats (booms and floats). Young leaves and shoots were sometimes eaten, and bark infusions were used for fever and wound washing. It is also a valued ornamental plant and a popular bonsai subject. In our offer, it is an impressive coastal collector’s plant.
Interesting facts
Each flower lives only one day, opening lemon-yellow with a dark throat and gradually reddening by evening – this change is due to anthocyanins. It is also a true coastal specialist: it grows right at the waterline, on sand, coral, and the edge of mangroves, tolerating salt and flooding where few other trees survive.
Summary
Hibiscus tiliaceus is a beautiful, spreading tree of tropical coasts with color-changing flowers and remarkable salt tolerance. Cultivation from seeds is easy after soaking the hard shell; in cooler climates, it is grown in pots as an exotic collector’s plant.
