Cyanea st.-johnii is a rare, endangered Hawaiian shrub in the bellflower family, endemic to Oahu's Koʻolau Mountains, where only about 70 plants survive on exposed, windy, cloud-covered ridges. It is a species, not a commonly grown garden plant, so care is largely a matter of conservation rather than home cultivation.
Family
Campanulaceae (Campanul family)
Grows as
Shrub
Light
Part shade
Water
Keep the soil evenly moist and never waterlogged; in its native cloud-zone habitat moisture comes frequently from mist and rain.
Soil
Free-draining, humus-rich mix with good organic content.
Temperature
Cool to mild, about 12 to 24 °C; protect from hard frost and heat.
How easy
Hard
Native range
Hawaiian Is. (Oʻahu)
Climate
wet tropical
About
Cyanea st.-johnii (formerly Rollandia st.-johnii) is a rare species of flowering plant in the bellflower family known by the common name St. John's rollandia. It is endemic to Oahu, where it is known only from the Koʻolau Mountains. It is a federally listed endangered species of the United States. Like other Cyanea it is known as haha in Hawaiian.
A 2007 report estimates 70 remaining individuals divided among seven occurrences in the upper elevations of the Koʻolau Mountains. The plant grows on top of ridges, in open, windy habitat within the cloud zone. The occurrences have been separated and isolated by habitat fragmentation.
Text excerpted from the Wikipedia article Cyanea st.-johnii by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.
Life form, climate and native range: World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 3.0), reformatted; see Plants of the World Online.