Native Plants

Santa Cruz Island Hollyfern

Arachniodes insularis

USDA symbol: ARIN22

perennial forb

Hawaii: native

If you’re passionate about native plants and have a soft spot for elegant ferns, the Santa Cruz Island hollyfern (Arachniodes insularis) might just capture your heart. This stunning Hawaiian native is more than just a pretty face in the shade garden – it’s a rare treasure that deserves our attention ...

Santa Cruz Island Hollyfern may be listed as rare in your area.
Global Conservation Status

Status: S2S3 | Vulnerable: Found only in a restricted range (even if abundant at some locations). Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals.

Santa Cruz Island Hollyfern: A Rare Hawaiian Native Worth Protecting

If you’re passionate about native plants and have a soft spot for elegant ferns, the Santa Cruz Island hollyfern (Arachniodes insularis) might just capture your heart. This stunning Hawaiian native is more than just a pretty face in the shade garden – it’s a rare treasure that deserves our attention and protection.

What Makes This Fern Special?

The Santa Cruz Island hollyfern is a perennial fern endemic to the Hawaiian Islands, meaning you won’t find it growing wild anywhere else on Earth. With its glossy, deeply divided fronds, this fern brings a touch of tropical elegance to any shaded corner. The name might suggest it’s only found on Santa Cruz Island, but this beauty actually graces several Hawaiian islands with its presence.

Despite being called a hollyfern, don’t expect the spiky leaves you’d associate with holiday holly. Instead, this fern produces gracefully arching fronds that create a lush, jungle-like atmosphere wherever they grow.

Where Does It Call Home?

This fern is exclusively native to Hawaii, where it grows naturally in the understory of native forests. Its distribution is limited to the Hawaiian island chain, making it a true island endemic.

  • Species observed
  • No observations

A Word of Caution: Rarity Matters

Here’s where things get serious, fellow plant lovers. The Santa Cruz Island hollyfern has a conservation status of S2S3, which means it’s considered rare and potentially vulnerable. This isn’t a plant you’ll find at your local garden center, nor should you expect to.

If you’re considering adding this fern to your collection, please ensure any plants come from responsibly sourced, legally propagated stock. Never collect plants from wild populations, as this can harm already vulnerable populations.

Growing Your Own: A Labor of Love

Successfully growing this Hawaiian beauty requires recreating a bit of tropical paradise in your garden. Here’s what you need to know:

Climate Requirements

  • USDA Hardiness Zones 10-11 only
  • High humidity levels
  • Protection from temperature extremes
  • Year-round warmth

Growing Conditions

  • Light: Filtered shade to deep shade (no direct sunlight)
  • Soil: Well-draining but consistently moist, rich in organic matter
  • Water: Regular watering to maintain soil moisture
  • Humidity: High humidity preferred (consider misting or humidity trays)

Garden Design Role

In the right climate, this fern makes an excellent choice for:

  • Shade gardens and woodland landscapes
  • Native Hawaiian plant collections
  • Understory plantings beneath larger trees
  • Container gardens in protected areas

As a facultative upland species, it typically prefers non-wetland conditions but can tolerate some moisture variation, making it somewhat adaptable to different garden situations within its preferred habitat.

The Bottom Line

The Santa Cruz Island hollyfern is undoubtedly a gorgeous addition to any tropical or subtropical garden, but it comes with responsibility. If you’re lucky enough to live in the right climate zone and can source plants ethically, this rare fern can be a rewarding challenge for experienced gardeners.

However, if you’re new to gardening or looking for easier alternatives, consider other native ferns from your region that might offer similar aesthetic appeal without the conservation concerns. Remember, the best garden choices are often the ones that support local ecosystems while being sustainable for both you and the environment.

For those committed to growing this special fern, your efforts contribute to the conservation of a unique piece of Hawaii’s natural heritage – and that’s something truly worth nurturing.

Arachniodes insularis is also known as...

Often we refer to plants by their common names. When shopping for plants the scientific name is the best way to positively identify the plant species you desire. But some plants have more than one name! While it doesn't happen often, nurseries might display one name while you're searching for another. Arachniodes insularis is also known as:

Arachniodes carvifolia auct. non | USDA symbol: ARCA15
Rumohra carvifolia auct. non | USDA symbol: RUCA6

Why do some plants have more than one name? Over time plant species may be renamed for a few reasons:

  1. Botanists in different regions named the same plant without knowing it had already been classified.
  2. A species was reclassified after scientific advances in, for example, DNA analysis.
  3. Slight variations within a species are sometimes mistakenly identified as entirely new species.

Classification

Group: Fern
Kingdom: Plantae - Plants
Subkingdom: Tracheobionta - Vascular plants
Division: Pteridophyta - Ferns
Class: Filicopsida
Order: Polypodiales
Family: Dryopteridaceae Herter - Wood Fern family
Genus: Arachniodes Blume - hollyfern

Species: Arachniodes insularis W.H. Wagner - Santa Cruz Island hollyfern

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA