Pua Kala: Growing Hawaii’s Rare Native Bellflower
If you’re passionate about Hawaiian native plants and conservation gardening, you’ve probably heard whispers about pua kala (Cyanea solenocalyx). This stunning member of the bellflower family is one of Hawaii’s botanical treasures – and unfortunately, one of its most endangered.
What Makes Pua Kala Special
Pua kala is a perennial tree native exclusively to Hawaii, where it naturally grows as a single-stemmed woody plant reaching heights of 13-16 feet or more. With its distinctive paddle-shaped leaves and tubular purple-blue flowers, this plant is a true showstopper that represents the unique beauty of Hawaiian flora.
You might also see this plant listed under its synonyms: Cyanea ovatisepala, Cyanea solenocalyx var. latifolia, or Cyanea wailauensis, but they all refer to the same remarkable species.
Where Pua Kala Grows Wild
This endemic Hawaiian species is found naturally on the islands of Molokai and Maui, where it grows in moist, shaded forest areas. Its distribution is limited to Hawaii, making it a truly special addition to any native plant collection.
- Species observed
- No observations
A Word of Caution: This Plant is Rare
Before we dive into growing tips, there’s something crucial you need to know: pua kala has a Global Conservation Status of S2, meaning it’s imperiled with typically only 6-20 occurrences remaining in the wild. This isn’t just rare – it’s critically rare.
If you’re interested in growing pua kala, please only source plants or seeds from reputable native plant nurseries or conservation organizations. Never collect from wild populations, as this could push the species closer to extinction.
Why Grow Pua Kala?
Despite its rarity challenges, there are compelling reasons to consider pua kala for your garden:
- Support conservation efforts by growing rare native species
- Create authentic Hawaiian landscapes with endemic plants
- Enjoy unique, eye-catching flowers that few gardeners get to experience
- Contribute to preserving Hawaiian botanical heritage
- Support native pollinators (though many original pollinators are now extinct)
Growing Conditions and Care
Pua kala is naturally a facultative wetland plant, meaning it usually grows in wetland areas but can adapt to other moist environments. Here’s what this tropical beauty needs to thrive:
Climate Requirements
- USDA Hardiness Zones 10-12 only (tropical and subtropical climates)
- High humidity levels
- Protection from strong winds
- Cool to moderate temperatures
Soil and Water Needs
- Moist, well-draining soil
- Consistent moisture without waterlogging
- Rich, organic soil similar to forest floor conditions
Light Requirements
- Partial to full shade
- Protection from intense direct sunlight
- Mimics natural forest understory conditions
Garden Design and Landscape Use
Pua kala works beautifully in:
- Native Hawaiian plant gardens
- Shade gardens with tropical themes
- Botanical collections focusing on rare species
- Conservation gardens
- Educational landscapes highlighting Hawaiian biodiversity
As a tree that can reach significant height, give pua kala plenty of space to grow and consider it an anchor plant in your design rather than a filler species.
The Bottom Line
Growing pua kala is both a privilege and a responsibility. While this plant offers unique beauty and contributes to conservation efforts, its extreme rarity means it’s not for casual gardeners. If you’re committed to providing the specific conditions it needs and can source plants responsibly, pua kala can be a meaningful addition to your Hawaiian native plant collection.
Remember: with only a handful of populations left in the wild, every responsibly grown pua kala plant represents hope for the species’ survival. That’s pretty special, don’t you think?