North America Native Plant

Island Grapefern

Botanical name: Sceptridium subbifoliatum

USDA symbol: SCSU13

Life cycle: perennial

Habit: forb

Native status: Native to Hawaii  

Synonyms: Botrychium subbifoliatum Brack. (BOSU)   

Island Grapefern: A Rare Hawaiian Treasure Worth Protecting Meet the island grapefern (Sceptridium subbifoliatum), one of Hawaii’s most elusive native ferns that’s captured the attention of botanists and conservationists alike. This isn’t your typical garden-variety fern – it’s a botanical mystery that might just be hanging on by a thread ...

Rare plant alert!

Region: Conservation status by state

Status: SH: Status is uncertain but is somewhere between the following rankings: Possibly Extinct: Known only from historical occurrences. Still some hope of rediscovery ⚘

Island Grapefern: A Rare Hawaiian Treasure Worth Protecting

Meet the island grapefern (Sceptridium subbifoliatum), one of Hawaii’s most elusive native ferns that’s captured the attention of botanists and conservationists alike. This isn’t your typical garden-variety fern – it’s a botanical mystery that might just be hanging on by a thread in the wild.

What Makes Island Grapefern Special?

The island grapefern belongs to a fascinating group of ferns known as grape ferns, named for their distinctive fertile fronds that somewhat resemble tiny grape clusters. As a perennial forb, this delicate Hawaiian native lacks the woody tissue you’d find in shrubs or trees, instead sporting soft, herbaceous growth that emerges from underground rhizomes year after year.

Also known scientifically by its former name Botrychium subbifoliatum, this fern has a unique two-part frond structure – one sterile leafy portion for photosynthesis and one fertile portion that produces spores for reproduction. It’s this grape-like fertile section that gives these ferns their charming common name.

Where Does Island Grapefern Call Home?

This endemic Hawaiian species is found exclusively in the Hawaiian Islands, making it a true island treasure. Its native range is limited to Hawaii, where it once grew in the understory of native forests.

A Conservation Concern

Here’s where things get serious – the island grapefern has a Global Conservation Status of SH, meaning it’s Possibly Extirpated. In plain English, this means the species is known only from historical records, and there’s just a glimmer of hope that it might still exist somewhere in the wild. Think of it as botanically missing in action.

This critical status makes the island grapefern incredibly rare and precious. If you’re lucky enough to encounter this species or seeds from responsibly sourced material, you’d be participating in conservation efforts rather than typical gardening.

Growing Island Grapefern: For Conservation Heroes Only

Given its possibly extirpated status, growing island grapefern isn’t about typical landscape design – it’s about conservation. If you’re considering cultivating this species, here’s what you need to know:

Ideal Growing Conditions

  • Climate: USDA Hardiness Zones 10-11 (tropical Hawaiian conditions)
  • Light: Filtered shade to partial shade, mimicking forest understory
  • Moisture: Consistent moisture without waterlogging
  • Soil: Well-draining but moisture-retentive, rich in organic matter

Responsible Cultivation

If you’re interested in growing island grapefern, work only with botanical gardens, conservation organizations, or researchers who have responsibly sourced material. Never collect from wild populations – they may be among the last of their kind.

This fern thrives in naturalistic shade gardens that replicate Hawaiian forest conditions. It’s perfect for conservation-minded gardeners who want to participate in preserving Hawaii’s unique botanical heritage.

Why Island Grapefern Matters

While ferns don’t offer nectar to pollinators like flowering plants, they play crucial roles in their ecosystems. Native Hawaiian ferns like the island grapefern contribute to the complex web of relationships that make Hawaiian forests unique. They provide habitat structure, contribute to soil health, and represent millions of years of evolutionary adaptation to island conditions.

The potential loss of species like island grapefern represents more than just one less plant in the world – it’s the loss of irreplaceable genetic diversity and a unique piece of Hawaii’s natural heritage.

The Bottom Line

The island grapefern isn’t a plant you’ll find at your local nursery, and that’s probably for the best. Its critically rare status means that any cultivation should be part of conservation efforts rather than casual gardening. If you’re passionate about Hawaiian native plants, consider supporting conservation organizations working to rediscover and protect species like this one.

Sometimes the most beautiful gardens are the ones that help preserve what we might otherwise lose forever. In the case of island grapefern, growing it responsibly means becoming part of a much larger – and more important – story of conservation and hope.

Island Grapefern

Classification

Group

Fern

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision
Division

Pteridophyta - Ferns

Subdivision
Class

Filicopsida

Subclass
Order

Ophioglossales

Family

Ophioglossaceae Martinov - Adder's-tongue family

Genus

Sceptridium Lyon - grapefern

Species

Sceptridium subbifoliatum (Brack.) W.H. Wagner - island grapefern

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