How to Grow Hau
iNaturalist
Hau
Hibiscus tiliaceus
shrubHau is a tropical, salt-tolerant shrub native to the Indo-Pacific region, valued for its large, showy yellow flowers that turn orange-red as they age. It grows rapidly in warm climates and produces lightweight, buoyant wood historically used for outriggers, fish traps, and net floats. The plant has been naturalized across tropical and subtropical regions worldwide and is important in traditional Pacific and Hawaiian cultures.
When should you plant Hau in your zone?
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Example Hau timeline · Pittsburgh, PA (Zone 6b)
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Plant Hau
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Hau
Late summer into fallBefore the first fall frost (≈ Nov 8)
Sample dates for Pittsburgh, PA. Sign up to get exact Hau dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 10-11; tolerates brief exposure to zone 9b temperatures
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Get my Hau timeline →Growth Stages
Seedling/Propagation
4-8 weeksYoung plants develop heart-shaped leaves; growth is rapid in warm conditions. Can be propagated from hardwood cuttings or seeds.
Keep soil consistently moist but not waterlogged. Provide bright, indirect light. Root cuttings in 2-4 weeks; seeds germinate in 2-3 weeks with scarification and warmth (75-85°F).
Establishment
2-3 monthsPlant develops stronger branching structure and deeper root system. Leaves are large, alternate, and heart-shaped with prominent veining.
Water regularly to establish deep roots. Apply 2-3 inches of mulch. Prune to shape if desired. Withhold excessive nitrogen to encourage flowering.
Vegetative Growth
OngoingVigorous shoot and leaf production; plant reaches mature height and spread. Dense canopy develops with abundant foliage.
Continue regular watering during dry periods. Light pruning to maintain shape. Reduce watering slightly once established. Tolerates coastal salt spray without damage.
Flowering
3-9 months (year-round in tropics)Large, 3-4 inch wide hibiscus flowers appear in leaf axils; bright yellow with dark red centers, aging to orange-red by evening. Flowers open in morning, close by evening (ephemeral).
Flowering may occur year-round in consistently warm climates, peak in warm season. Deadheading extends flowering but not necessary. Provide adequate water and sunlight for best bloom.
Fruiting/Seed Production
6-8 weeks from flower to mature seed capsuleAfter flower drop, round, corky seed capsules develop. Capsules are buoyant and papery-textured, split open to release winged seeds.
Allow spent flowers to mature into seed capsules if propagation desired. Seeds can be collected and dried for storage. Self-seeds readily in warm climates.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Prune infested leaves; spray with horticultural oil or neem oil; encourage natural predators
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Spray with strong water stream to dislodge; apply insecticidal soap or neem oil; reflective mulch as deterrent
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Remove with cotton swab dipped in rubbing alcohol; spray neem oil; encourage parasitic wasps
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Hand-remove; spray horticultural oil during dormant season; prune heavily infested branches
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Increase humidity; spray with water; apply miticide if severe; ensure adequate irrigation
Uses
Edible flowers and traditional tea
CulinaryIn Hawaiian and Pacific island cultures, hau flowers are eaten fresh and have a mild, slightly tangy flavor. Flower buds and leaves can be steeped into a traditional herbal tea known for its subtle, pleasant taste and possible digestive properties. [source]
Lightweight boat building and traditional crafts
CraftThe wood is exceptionally buoyant and lightweight, historically used for Hawaiian and Pacific outrigger canoes, fishing net floats, and fish traps. Modern artisans use the wood for carved items, bowls, and decorative pieces due to its workability and unique grain. [source]
Fiber and bark cordage
HouseholdThe inner bark produces strong, durable fibers that can be stripped, dried, and twisted into cordage, rope, and twine. Traditionally used in Pacific island communities for fishing nets and binding applications. [source]
Traditional herbal remedy
MedicinalIn traditional medicine systems across the Pacific and Southeast Asia, various plant parts (bark, leaves, flowers, roots) are used to address inflammation, digestive issues, and skin conditions. Modern research has begun investigating bioactive compounds in Hibiscus tiliaceus. [source]
Pollinator and wildlife support
WildlifeThe abundant flowers attract native bees, butterflies, hummingbirds, and other pollinators. The dense foliage provides shelter and nesting sites for birds. Seeds and buoyant capsules aid in dispersal across coastal habitats. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Hau is typically not harvested like a crop plant. Flowers can be picked in morning for arrangements; they last only one day. Seeds mature in 6-8 weeks after flowering and can be collected when capsules dry and brown. Wood can be harvested for crafting once plant is 3-4 years old and sufficiently mature. Bark strips can be harvested for fiber use without harming the tree.
Fun Facts
- 🌱 Hau flowers are ephemeral, opening bright yellow in the morning and closing in the evening after turning orange-red—a color change caused by pH shifts in the flower petals.
- 🌱 The wood is so buoyant that it was used by ancient Hawaiian and Polynesian voyagers for their double-hulled outrigger canoes (waʻa kaulua), enabling long-distance ocean exploration across the Pacific.
- 🌱 Hau has naturalized extensively across tropical coastlines worldwide and is now considered invasive in some regions, spreading through buoyant seeds that float across ocean currents for months without losing viability.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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