North America Native Plant

Parasitic Maiden Fern

Botanical name: Thelypteris parasitica

USDA symbol: THPA4

Life cycle: perennial

Habit: forb

Native status: Non-native, reproduces and persists in the wild in Hawaii âš˜ Native to Pacific Basin excluding Hawaii  

Synonyms: Christella parasitica (L.) Lév. (CHPA41)  âš˜  Cyclosorus parasiticus (L.) Farw. (CYPA21)  âš˜  Dryopteris parasitica (L.) Kuntze (DRPA14)   

Parasitic Maiden Fern: A Tropical Fern for Pacific Gardens The parasitic maiden fern (Thelypteris parasitica) might have an ominous-sounding name, but don’t let that scare you away from this graceful tropical fern. Known locally as kilkuld in Palau, this perennial fern brings a lush, tropical feel to shaded garden spaces ...

Parasitic Maiden Fern: A Tropical Fern for Pacific Gardens

The parasitic maiden fern (Thelypteris parasitica) might have an ominous-sounding name, but don’t let that scare you away from this graceful tropical fern. Known locally as kilkuld in Palau, this perennial fern brings a lush, tropical feel to shaded garden spaces across the Pacific region.

What is the Parasitic Maiden Fern?

Despite being classified botanically as a forb, Thelypteris parasitica is actually a true fern that lacks the woody tissue found in shrubs and trees. This perennial plant produces typical fern fronds with a pinnate (feather-like) structure that creates an elegant, arching appearance. The bright green foliage adds instant tropical appeal to any shaded garden space.

You might also encounter this fern under several scientific synonyms, including Christella parasitica, Cyclosorus parasiticus, and Dryopteris parasitica – all referring to the same species.

Where Does It Grow?

This fern is native to the Pacific Basin region but has established itself beyond its original range. Today, you’ll find parasitic maiden fern growing in Hawaii, Guam, and Palau. In Hawaii specifically, it’s considered a non-native species that has naturalized and reproduces on its own in the wild.

Garden Appeal and Landscape Use

The parasitic maiden fern works beautifully as an understory plant in tropical and subtropical gardens. Its medium size and graceful fronds make it perfect for:

  • Ground cover in shaded areas
  • Adding texture to woodland gardens
  • Creating lush, tropical atmosphere
  • Filling in naturalized garden spaces

The fern’s facultative wetland status means it’s quite versatile – it can handle both moist and moderately dry conditions, making it adaptable to various garden situations.

Growing Conditions and Care

If you’re considering adding this fern to your garden, here’s what it needs to thrive:

Climate: Best suited for USDA hardiness zones 10-12, where temperatures stay consistently warm and tropical.

Light: Prefers partial to full shade – direct sunlight can scorch the delicate fronds.

Soil: Thrives in moist, well-draining soil enriched with organic matter. Avoid waterlogged conditions despite its wetland tolerance.

Water: Keep soil consistently moist but not soggy. Regular watering during dry periods will keep fronds looking their best.

Humidity: Like most tropical ferns, it appreciates high humidity levels.

Things to Consider

While the parasitic maiden fern can be an attractive addition to appropriate gardens, it’s worth noting that it’s non-native to Hawaii and has established itself in the wild. If you’re gardening in Hawaii or other Pacific locations, consider exploring native fern alternatives that can provide similar aesthetic benefits while supporting local ecosystems.

Since this is a fern rather than a flowering plant, it won’t provide direct benefits to pollinators like bees and butterflies. However, it can contribute to overall garden biodiversity and provide habitat structure for other wildlife.

The Bottom Line

Parasitic maiden fern offers tropical gardeners an adaptable, attractive fern option for shaded spaces. Its graceful fronds and tolerance for varying moisture levels make it a relatively low-maintenance choice for the right climate. Just remember to consider native alternatives first, especially if you’re gardening in areas where this species has naturalized beyond its original range.

Whether you call it parasitic maiden fern, kilkuld, or any of its scientific synonyms, this tropical fern can add that lush, jungle-like feeling to your shaded garden spaces – as long as you can provide the warm, humid conditions it craves.

Wetland Status

The rule of seasoned gardeners and landscapers is to choose the "right plant for the right place" matching plants to their ideal growing conditions, so they'll thrive with less work and fewer inputs. But the simplicity of this catchphrase conceals how tricky plant selection is. While tags list watering requirements, there's more to the story.

Knowing a plant's wetland status can simplify the process by revealing the interaction between plants, water, and soil. Surprisingly, many popular landscape plants are wetland species! And what may be a wetland plant in one area, in another it might thrive in drier conditions. Also, it helps you make smarter gardening choices and grow healthy plants with less care and feeding, saving you time, frustration, and money while producing an attractive garden with greater ecological benefits.

Regions
Status
Moisture Conditions

Hawaii

FAC

Facultative - Plants with this status can occur in wetlands and non-wetlands

FAC

South Pacific Islands

Parasitic Maiden Fern

Classification

Group

Fern

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision
Division

Pteridophyta - Ferns

Subdivision
Class

Filicopsida

Subclass
Order

Polypodiales

Family

Thelypteridaceae Ching ex Pic. Serm. - Marsh Fern family

Genus

Thelypteris Schmidel - maiden fern

Species

Thelypteris parasitica (L.) Fosberg - parasitic maiden fern

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