North America Native Plant

Caribbean Spleenwort

Botanical name: Asplenium rhomboidale

USDA symbol: ASRH4

Life cycle: perennial

Habit: forb

Native status: Native to Puerto Rico  

Synonyms: Asplenium sintenisii Hieron. (ASSI6)   

Caribbean Spleenwort: A Delicate Native Fern for Tropical Gardens Meet the Caribbean spleenwort (Asplenium rhomboidale), a charming little fern that calls Puerto Rico home. While it might not be the showiest plant in your garden, this petite native has a quiet elegance that makes it a wonderful addition to the ...

Caribbean Spleenwort: A Delicate Native Fern for Tropical Gardens

Meet the Caribbean spleenwort (Asplenium rhomboidale), a charming little fern that calls Puerto Rico home. While it might not be the showiest plant in your garden, this petite native has a quiet elegance that makes it a wonderful addition to the right tropical landscape.

What Is Caribbean Spleenwort?

Caribbean spleenwort is a perennial fern that belongs to the spleenwort family, known for their distinctive frond shapes. The name rhomboidale gives us a clue about its appearance – this fern produces small, diamond-shaped leaflets that create a delicate, lacy texture. You might also see it listed under its synonym, Asplenium sintenisii, in some older botanical references.

Where Does It Grow Naturally?

This little fern is native to Puerto Rico, where it has adapted to the island’s tropical climate and specific growing conditions. As an endemic species, it plays an important role in Puerto Rico’s native ecosystem.

Should You Plant Caribbean Spleenwort?

If you’re gardening in Puerto Rico or other tropical zones (USDA zones 10-11), Caribbean spleenwort can be a lovely addition to your native plant palette. Here’s what makes it appealing:

  • It’s a true native, supporting local ecosystem health
  • Perfect for adding delicate texture to shaded areas
  • Low-maintenance once established in the right conditions
  • Ideal for rock gardens or naturalistic plantings

However, it’s worth noting that information about this particular fern is limited, so it might be challenging to source and may require some trial and error to grow successfully.

Growing Caribbean Spleenwort Successfully

Like most tropical ferns, Caribbean spleenwort thrives in conditions that mimic its natural habitat:

Light Requirements

This fern prefers shaded to partially shaded locations. Direct tropical sun will likely scorch its delicate fronds, so look for spots that receive filtered light or morning sun with afternoon shade.

Soil and Water Needs

Well-draining soil with consistent moisture is key. Think moist but not soggy – the soil should never dry out completely, but standing water will cause root problems. Adding organic matter like compost or leaf mold can help create the ideal growing medium.

Climate Considerations

This fern is only suitable for truly tropical climates (zones 10-11). It needs warm temperatures year-round and high humidity to thrive. If you’re outside these zones, it might work as a greenhouse or indoor plant, though success isn’t guaranteed.

Landscaping with Caribbean Spleenwort

Caribbean spleenwort works beautifully in several garden settings:

  • Rock gardens: Its small size makes it perfect for tucking into crevices
  • Shade gardens: Adds delicate texture among larger shade plants
  • Native plant gardens: Essential for authentic Puerto Rican plant communities
  • Container gardens: Great for small-space tropical gardening

A Note About Sourcing

Since Caribbean spleenwort is relatively uncommon in cultivation and specific to Puerto Rico, finding plants or spores might require some detective work. Check with local native plant societies, botanical gardens, or specialty fern suppliers. Always ensure any plants you acquire are ethically and legally sourced.

The Bottom Line

Caribbean spleenwort may not be the easiest fern to find or grow, but for tropical gardeners interested in native plants, it offers a unique opportunity to support local biodiversity. Its delicate beauty and ecological value make it worth considering if you can provide the right growing conditions and manage to source it responsibly.

While we’d love to share more specific growing tips, the limited research on this particular species means some experimentation may be needed. Consider it part of the adventure of native gardening – sometimes the most rewarding plants are the ones that teach us something new!

Caribbean Spleenwort

Classification

Group

Fern

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision
Division

Pteridophyta - Ferns

Subdivision
Class

Filicopsida

Subclass
Order

Polypodiales

Family

Aspleniaceae Newman - Spleenwort family

Genus

Asplenium L. - spleenwort

Species

Asplenium rhomboidale Desv. - Caribbean spleenwort

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