Japanese climbing fern: Lygodium japonicum
Lygodium japonicum may be confused with Lygodium microphyllum, another
invasive, nonnative plant in Florida. L. japonicum leaflets are more dissected and lobed than those of L. microphyllum.
Look for first
- Tangle of wiry, twining fronds
- Fern-type leaflets with hairs on undersides
- Sporangia under curled leaflet margins
||Leaves: Twining fronds to 90 ft. in length; main leaf stalk (rachis) wiry, twining; leaflets highly dissected or lobed, arranged on branches off the rachis, their lower surfaces pubescent with short curving hairs; the lobes pointed or rounded at the tips, flat at the margins when no sporangia (spore-producing sacs) present (then called "sterile" leaflets). "Fertile" leaflets contracted in shape, with margins curled over rows of sporangia.
||Stems: Thin, wiry, dark rhizomes (underground stems) or runners, sometimes forming layered mats on the ground surface.
||Flowers: None. Ferns are a spore-releasing class of vascular plants.
||Spores: Many thousands of tiny spores released per plant and carried by wind, dust, animals, clothes and equipment.
Japanese climbing fern is a highly invasive non-native plant infesting public conservation lands in North and West Florida and present in much of the southeastern U.S. It grows in moist or dry woods, along ditches and rivers, and in various disturbed sites. It tolerates sun and shade.
It was likely introduced into Florida as an ornamental plant in 1932. Japanese climbing fern appears to be rapidly spreading in North and West Florida, but also may pose a significant threat to Central Florida.
Native to Eastern Asia, temperate to tropical zones. Escaped in the United States, from the Carolinas through Georgia and Florida and west to Texas and Arkansas. In Florida, most common in North and West Florida but spreading down the pennisula and has been found as far south as Collier and Broward counties.
Like Old World climbing fern (Lygodium microphyllum), Japanese climbing fern climbs over shrubs and into the tops of trees where its dense canopies shade out and eliminate the vegetation below.
Why Japanese Climbing Fern must be managed
Japanese climbing fern forms dense tangled masses over ground cover and shrubs; its dense canopy eliminates native vegetation.
Japanese climbing fern (Lygodium japonicum)
Image Credit: Sandra Murphy-Pak, Center for Aquatic and Invasive Plants, University of Florida.