Hawaiian Names with Diacritics
- Fishbone fern
- Narrow swordfern
- Sword fern
- Aspidium tuberosum
- Nephrolepis tuberosa
- Polypodium cordifolium
Endangered Species Status
Plant Form / Growth Habit
- Non-Woody, Spreading
Mature Size, Height (in feet)
- Fern/Fern-like, Medium, 1 to 3
Mature Size, Width
Kupukupu is known to have a 1- to 4-foot spread.
Long lived (Greater than 5 years)
- Erosion Control
- Ground Cover
- Specimen Plant
Additional Landscape Use Information
Kupukupu produce subterranean round tubers on stolons and are easy to propagate. Companion plants are ʻōhiʻa, koa and wiliwili. An excellent groundcover in sun and shade. The dense fronds control weeds. They can also grow up trees, tree ferns and rock walls.
They do well as containers plants in part to full sun with regular watering. 
Be sure to get plants from reputable sources as some kupukupu sold in local garden shops are not from Hawaiʻi.
Source of Fragrance
- No Fragrance
Plant Produces Flowers
Additional Plant Texture Information
Fronds range from 12 to 28 inches long and about 2 to 3 inches wide. Fronds are pinna or feather-shaped and slightly toothed.
- Light Green
- Medium Green
Additional Pest & Disease Information
In general kupukupu is pest and disease free, but may be infested occasionally with ants, mealy bugs, scale and slugs.
Kupukupu appreciate a 13-13-13 slow release fertilizer with minor elements every six months for plants in pots or planted in the ground. For larger potted ferns showing poor color or not producing crosiers (fiddleheads or emerging fronds) use a complete fertilizer at half the recommended strength. Do not till solid fertilizers into soil since ferns have a shallow root system. 
Can be mildly aggressive and grow into other beds, but easy to control. Dead leaves can be removed for a better appearance every couple of years.
Additional Water Information
Kupukupu grows in dry, moist and wet conditions. Under cultivation, grow in moist conditions for best overall appearance. Never allow them to sit in water as the fronds will yellow, defoliate and often die. [Rick Barboza, Hui Kū Maoli Ola]
Soil must be well drained
- Full sun
- Partial sun
Additional Lighting Information
Kupukupu does equally well in full sun or shade, but differs slightly in form and color depending on growing location.
These ferns should be space at about 18 inches apart and staggered. If planted too close the plants out compete each other and eventually die back in a short time. [Rick Barboza, Hui Kū Maoli Ola]
This is the only Nephrolepis species in Hawaiʻi to produce underground tubers with can be removed with a small piece of stolon and be potted or transplanted.
Natural Zones (Elevation in feet, Rainfall in inches)
- 1000 to 1999, 50 to 100 (Mesic)
- 1000 to 1999, Greater than 100 (Wet)
- 2000 to 2999, 50 to 100 (Mesic)
- 2000 to 2999, Greater than 100 (Wet)
- 3000 to 3999, 50 to 100 (Mesic)
- 3000 to 3999, Greater than 100 (Wet)
- 4000 to 4999, 50 to 100 (Mesic)
- 4000 to 4999, Greater than 100 (Wet)
Additional Habitat Information
Kupukupu is locally common as a terrestrial or an epiphyte in mesic to wet forests from about 1,445 to 5,000 feet.
Kupupukupu (Nephrolepis spp.) are members of Lomariopsidaceae.  There are several common naturalized swordferns and will hybridize with the native species.
The generic name Nephrolepis is derived from the Greek nephros, kidney, and lepis, scale, in reference to the kidney-shaped indusia (sori covering).
The specific epithet cordifolia is from the Latin cordis, heart, and folium, leaf. Daniel Palmer comments: "If interpreted as "heart-shaped leaf," a puzzling reference to the pinna shape of this fern." 
This is the only Nephrolepis species, or swordfern, in Hawaiʻi that produce underground tubers on the stolons.
Early Hawaiian Use
The fronds were fashioned as into lei for the wrists and ankles called kūpeʻe or as haku for the head. 
Kupukupu is used today in lei as it was with early Hawaiians. 
There are three non-native recognized cultivars for this species: cv. 'Duffii', cv. 'Petticoats', and cv. 'Tessellata'. 
 Kay Lynch, Lāʻau Hawaiʻi
 http://www2.bishopmuseum.org/HBS/botany/cultivatedplants/?pge=3&str=nephrolepis&fld= [Accessed on 10/1/08]
 Taxon 55 August 2006: Fern Classification, by Alan R. Smith et al., page 14.
 "Container Gardening in Hawaii" by Janice Crowl, page 53.
 "Nā Lei Makamae--The Treasured Lei" by Marie A. McDonald & Paul R. Weissich, pages 59-60.
 "Hawaiʻi's Ferns and Fern Allies" by Daniel Palmer, page 189.
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Other Nursery Profiles for Nephrolepis cordifolia