Trembleya: A Tropical Shrub for Hawaii’s Gardens
If you’ve been wandering through Hawaii’s gardens and spotted a lovely shrub with delicate purple-pink flowers, you might have encountered Trembleya. This perennial shrub has quietly made itself at home in the Hawaiian islands, though it’s actually a South American native that decided Hawaii was pretty nice too.
What is Trembleya?
Trembleya is a multi-stemmed woody shrub that typically grows to about 13-16 feet tall, though it can sometimes stretch taller or stay more compact depending on growing conditions. Like many shrubs, it sends up several stems from near the ground, creating a full, bushy appearance that makes it an attractive addition to tropical landscapes.
Where Does Trembleya Grow?
While Trembleya originally hails from South America (particularly Brazil), it has established itself in Hawaii, where it now reproduces naturally without human intervention. It’s currently found growing wild throughout the Hawaiian islands.
Should You Plant Trembleya in Your Garden?
Here’s where things get a bit nuanced. Trembleya isn’t native to Hawaii, but it’s also not currently listed as invasive or problematic. This puts it in a gray area for gardeners who care about ecological impact. While it won’t actively harm your garden, native plant enthusiasts might prefer to choose indigenous Hawaiian species that better support local wildlife and ecosystems.
Growing Conditions and Care
If you decide to grow Trembleya, you’ll need to provide tropical or subtropical conditions. Here’s what this shrub prefers:
- USDA Hardiness Zones 10-11 (essentially year-round warm weather)
- Well-draining soil that doesn’t stay soggy
- Regular watering, especially during dry periods
- Protection from strong winds that might damage the stems
- Partial to full sun exposure
Aesthetic Appeal and Garden Role
Trembleya brings a soft, romantic touch to tropical gardens with its purple to pink flowers. As a shrub, it works well as:
- A specimen plant in mixed borders
- Part of a tropical shrub collection
- Background plantings for shorter flowers
- Informal hedging (though it may need occasional pruning to maintain shape)
Pollinator and Wildlife Benefits
While specific data on Trembleya’s wildlife benefits is limited, flowering shrubs like this one typically attract pollinators such as bees and butterflies. However, since it’s not native to Hawaii, it may not provide the same level of support to local wildlife as indigenous plants would.
Native Alternatives to Consider
If you’re interested in supporting Hawaii’s native ecosystem while still getting beautiful flowering shrubs, consider these native alternatives:
- ʻŌhiÊ»a lehua (Metrosideros polymorpha) – iconic Hawaiian tree/shrub with red flowers
- Naupaka (Scaevola taccada) – coastal shrub with unique white flowers
- Hawaiian hibiscus species – various native hibiscus with showy blooms
The Bottom Line
Trembleya is a pleasant enough shrub that can add tropical flair to appropriate gardens in Hawaii. While it’s not causing major ecological problems, it’s also not actively benefiting native Hawaiian ecosystems. If you already have Trembleya in your garden, there’s no urgent need to remove it. But if you’re planning new plantings, consider giving native Hawaiian species a chance to shine – they’re often just as beautiful and much better for local wildlife.
Remember, successful gardening isn’t just about what looks good; it’s about creating spaces that work harmoniously with the local environment. Whether you choose Trembleya or native alternatives, the key is providing the right growing conditions and enjoying the process of gardening in paradise.
