Lygodium microphyllum aka Small Leaf Climbing Fern

Lygodium microphyllum is a fern that stays green and climbs like a vine. People call it old world climbing fern or climbing maidenhair fern. It belongs to the Lygodiaceae family. It is native to tropical Africa and South Africa. Useful Tropical Plants also lists its range across tropical Asia. It grows at forest edges and climbs shrubs and trees. The same source records it on dry, open slopes.

Its long fronds are pinnate, with leaflets along an axis. These fronds let the fern climb. Useful Tropical Plants gives a height of 33 feet [10 metres]. NC State reports fronds reaching 90 feet [27.4 metres]. These sizes do not define a clear garden range. Green stems are wiry and smooth, with bends like zigzags. Dark brown, wiry rhizomes, or creeping stems, form mats below. The green leaflets have fertile and sterile forms. Sterile leaflets are oblong, with smooth edges. Small folds on fertile leaflet edges shelter sporangia, which hold spores. The fern has no flowers but makes many spores. Wind and water spread them, and they sprout with ease.

This fern grows fast in moist or wet soil. It also grows in places where water stands. NC State notes growth from deep shade to full sun. Useful Tropical Plants suggests shade for the roots. It suggests letting the climbing growth reach the sun. The fern prefers neutral to slightly acidic soil. NC State lists USDA hardiness zones 9a through 12b. Its fast spread means it needs much care. NC State reports no major pest insect or disease problems.

People have grown it to hide structures and cast shade. But its spread can outweigh these garden uses. In Florida, it can invade moist sites with no prior disturbance. Thick growth covers shrubs and trees and can kill them. Low mats also smother smaller native plants. It poses a grave threat to swamp forests and other wetlands. Growth on trees can carry fire into their crowns. NC State notes that the North Carolina Invasive Plant Council lists it.

People weave its stems into baskets, hats, and bags. They also use them as ties and to make small boxes. Records note the use of very young leaves as cooked greens. Folk uses include leaf mixtures for dysentery and skin complaints. These uses do not prove that treatment is safe or works. Useful Tropical Plants notes no known reports of toxicity for this species. That lack of reports does not prove safety for people or pets.