North America Native Plant

Clamshell Orchid

Botanical name: Prosthechea cochleata var. cochleata

USDA symbol: PRCOC

Life cycle: perennial

Habit: forb

Native status: Native to Puerto Rico âš˜ Native to the U.S. Virgin Islands  

Synonyms: Anacheilium cochleatum (L.) Hoffmanns. (ANCO10)  âš˜  Encyclia cochleata (L.) Dressler (ENCO3)  âš˜  Epidendrum cochleatum L. (EPCO3)   

Growing the Enchanting Clamshell Orchid: A Caribbean Native Treasure Meet one of the Caribbean’s most captivating native orchids – the clamshell orchid (Prosthechea cochleata var. cochleata). This remarkable epiphytic orchid gets its whimsical common name from its unique upside-down flowers that resemble tiny clamshells. If you’re looking to add a ...

Growing the Enchanting Clamshell Orchid: A Caribbean Native Treasure

Meet one of the Caribbean’s most captivating native orchids – the clamshell orchid (Prosthechea cochleata var. cochleata). This remarkable epiphytic orchid gets its whimsical common name from its unique upside-down flowers that resemble tiny clamshells. If you’re looking to add a touch of tropical elegance to your collection while supporting native biodiversity, this enchanting orchid deserves serious consideration.

What Makes the Clamshell Orchid Special?

The clamshell orchid is truly a conversation starter in any garden or collection. Its most distinctive feature is its unusual flower presentation – the dark purple to nearly black lip (labellum) sits at the top like a hood, while the green-yellow petals and sepals dangle below. This upside-down arrangement is completely opposite to most orchids, creating an almost shell-like appearance that’s impossible to ignore.

What’s even more fascinating is that this perennial orchid produces flowers sequentially on the same spike, meaning you can enjoy blooms for several months. The flowers emerge one at a time from a flattened, shell-shaped bract, adding to the plant’s distinctive character.

Native Heritage and Geographic Distribution

This orchid is a true Caribbean native, naturally occurring in Puerto Rico and the U.S. Virgin Islands. By choosing to grow this species, you’re not only adding beauty to your space but also supporting the preservation of native Caribbean flora. The plant grows naturally as an epiphyte in its native tropical forests, where it clings to tree bark and absorbs moisture and nutrients from the humid air.

Is the Clamshell Orchid Right for Your Garden?

The clamshell orchid is perfect for gardeners who:

  • Love unique, conversation-starting plants
  • Want to support native biodiversity
  • Enjoy orchid collecting and cultivation
  • Have greenhouse space or live in tropical climates (USDA zones 10-12)
  • Appreciate long-blooming plants with sequential flowering

However, this orchid might not be the best choice if you’re a beginner gardener or looking for low-maintenance outdoor plants in temperate climates. Like most orchids, it requires specific growing conditions and consistent care.

Growing Conditions and Care

Successfully growing the clamshell orchid means mimicking its native epiphytic environment:

Light Requirements: Provide bright, indirect light. In its native habitat, it grows under the forest canopy, so avoid direct sunlight which can scorch the leaves.

Temperature: This tropical native thrives in warm conditions, ideally between 65-85°F (18-29°C). It’s only hardy in USDA zones 10-12, so most gardeners will need to grow it indoors or in a greenhouse.

Humidity: High humidity (60-80%) is essential. Use humidity trays, regular misting, or a humidifier to maintain proper moisture levels in the air.

Growing Medium: Use a well-draining orchid bark mix or mount the plant on a piece of cork bark or hardwood. The roots need excellent drainage and air circulation.

Planting and Care Tips

Watering: Water when the growing medium is nearly dry, typically once or twice a week. Water thoroughly but ensure excess water drains away completely. In winter, reduce watering frequency.

Fertilizing: Feed monthly with a balanced orchid fertilizer diluted to quarter strength during the growing season (spring through fall).

Air Circulation: Provide good air movement around the plant to prevent fungal issues and mimic the breezy conditions of its native habitat.

Repotting: Repot every 2-3 years or when the growing medium breaks down, typically in spring after flowering.

Garden Design and Landscape Role

The clamshell orchid works beautifully in several garden settings:

  • Tropical orchid collections and specialty gardens
  • Greenhouse displays where its unique flowers can be appreciated up close
  • Indoor plant collections in bright bathrooms or sunrooms
  • Mounted displays that showcase its epiphytic nature

In landscape design, use it as an accent plant that draws attention and sparks curiosity. Its compact size makes it perfect for small spaces, and its sequential blooming habit provides months of interest.

Supporting Pollinators and Wildlife

In its native range, the clamshell orchid plays an important role in supporting specialized pollinators. While these specific pollinators may not be present in cultivation, growing this native species helps preserve genetic diversity and supports conservation efforts for Caribbean flora.

The Bottom Line

The clamshell orchid is a delightful choice for orchid enthusiasts and native plant lovers who can provide the warm, humid conditions it needs. While it requires more specialized care than typical houseplants, the reward of those unique upside-down flowers and the satisfaction of growing a Caribbean native make it well worth the effort. Plus, you’ll have the coolest conversation starter in any plant collection!

Remember to source your plants responsibly from reputable orchid nurseries that practice sustainable cultivation methods. This ensures you’re getting a healthy plant while supporting ethical horticultural practices.

Clamshell Orchid

Classification

Group

Monocot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Liliopsida - Monocotyledons

Subclass

Liliidae

Order

Orchidales

Family

Orchidaceae Juss. - Orchid family

Genus

Prosthechea Kn. & Westc. - appendage orchid

Species

Prosthechea cochleata (L.) W.E. Higgins - clamshell orchid

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