Hawaiian Giant Rhubarb Plant Care
Gunnera petaloidea Gaudich.
Updated · Sources · How we source care data
Gunnera petaloidea is a species of Gunnera endemic to Hawaii on the islands Kauai, Oahu, Molokai, Maui, and Hawaii. It is found on slopes which receive heavy precipitation at an altitude between 700–1,830 m (2,300–6,000 ft) but mostly between 920–1,300 m (3,020–4,270 ft).
Every 3–5 days
Full sun to part shade
50–75°F
60–80%
At a glance
How do you care for Hawaiian Giant Rhubarb?
Water Hawaiian Giant Rhubarb every 3–5 days, letting the top layer of soil dry out between waterings, and give it full sun to part shade. It prefers temperatures of 50–75°F (10–24°C) and 60–80% humidity. Fertilize it every 6 months during the growing season.
Where Is the Hawaiian Giant Rhubarb Native To?
What Is the Hawaiian Giant Rhubarb?
Hawaiian Giant Rhubarb (Gunnera petaloidea) belongs to the Gunneraceae family within the Gunnera genus. Hawaiian Giant Rhubarb is native to Hawaii on the islands Kauai, Oahu, Molokai, Maui, and Hawaii. Hawaiian Giant Rhubarb is also known as Petal-like Gunnera.
Hawaiian Giant Rhubarb displays a large, spreading perennial growth habit, reaching up to 6 ft tall with a spread of approximately 10 ft. Hawaiian Giant Rhubarb produces small, inconspicuous flowers on tall spikes.
Leaf size: approximately 36 inches.
How Often Should You Water a Hawaiian Giant Rhubarb?
Gunnera petaloidea requires watering every 3–5 days. Allow the top layer of soil to dry between waterings to prevent root rot. Reduce watering frequency during winter when growth slows.
Watering Frequency
Every 3–5 days
Let soil partially dry between waterings
What Light Does the Hawaiian Giant Rhubarb Need?
Hawaiian Giant Rhubarb thrives in full sun to part shade.
Light Requirement
Full sun to part shade
What Temperature and Humidity Does the Hawaiian Giant Rhubarb Prefer?
Gunnera petaloidea grows best at temperatures of 50–75°F. Hawaiian Giant Rhubarb prefers humidity levels of 60–80%. A pebble tray or humidifier helps maintain adequate moisture around the plant.
Temperature
50–75°F
Humidity
60–80%
What Soil Mix Works Best for a Hawaiian Giant Rhubarb?
Rich, moist soil with good drainage and high organic matter content. Good drainage is essential for Hawaiian Giant Rhubarb to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Hawaiian Giant Rhubarb?
Feed Hawaiian Giant Rhubarb every 6 months during the growing season (spring and summer) with a balanced fertilizer diluted to the strength on the label.
Pause feeding in autumn and winter, when growth slows, and never fertilize dry soil — water first.
Fertilizing
Every 6 months
During the growing season
The PlantoScan app can remind you when to water and when to fertilize each plant.
How Do You Repot a Hawaiian Giant Rhubarb?
Divide and repot every 3-5 years in early spring. Choose a pot one size larger than the current container, and ensure it has drainage holes to allow excess water to escape.
How Do You Propagate a Hawaiian Giant Rhubarb?
Hawaiian Giant Rhubarb can be propagated through division of rhizomes, seeds. Similar propagation techniques also apply to gunnera aequatoriensis plant care, which shares the same genus.
Is the Hawaiian Giant Rhubarb Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Hawaiian Giant Rhubarb, so we can't confirm whether it is safe for cats and dogs. Keep pets from chewing it as a precaution.
This is a general caution, not veterinary or medical advice. If your pet ate a plant, contact your vet or animal poison control.
See all plants toxic to cats and plants toxic to dogs.
What Pests and Diseases Affect the Hawaiian Giant Rhubarb?
Hawaiian Giant Rhubarb is susceptible to slugs, snails, caterpillars. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.
Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.
What USDA Hardiness Zone Does the Hawaiian Giant Rhubarb Need?
Hawaiian Giant Rhubarb grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Hawaiian Giant Rhubarb is native to Hawaii on the islands Kauai, Oahu, Molokai, Maui, and Hawaii. In cooler regions, grow Hawaiian Giant Rhubarb as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 12a
Keep exploring plants
Hawaiian Giant Rhubarb is one of many species covered in the complete plant care and identification guide, which groups plants by genus, attribute, and popularity.
It belongs to the Gunnera genus — compare its care with other Gunnera species on PlantoScan.
Gunnera is part of the Gunneraceae plant family — browse all Gunneraceae genera and species.
Hawaiian Giant Rhubarb thrives in bright light and direct sun — see other bright-light plants.
More Gunnera Species
Other Gunnera species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Gunnera petaloidea Gaudich., family Gunneraceae (first published in Voy. Uranie : 512 (1830)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Hawaiian Giant Rhubarb, so we can't confirm whether it is safe for cats and dogs. Checked against the ASPCA plant list; any other toxicity note on this page comes from PlantoScan's plant database.
- Hardiness zone: USDA Zone 12a, calculated from the plant's minimum temperature.
- Care values(watering, light, temperature, humidity, soil, fertilizing): PlantoScan's plant database, filtered by automatic plausibility checks — values that fail them are hidden. How we source and check plant data.
Spotted a mistake? Email info@upvision.media with the page link — we check and correct reported errors.
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