Japanese Climbing Fern (Lygodium japonicum) is a good case in point. They were once native to India then spread into eastern Asia, the tropical parts of Australia and the Pacific Islands. Sometime late in the 1800s some jackanapes decided to bring some home to Georgia because they probably thought it “looked pretty.” Well, like some space alien on a rampage, it has since spread extensively across the U.S. South.
The fern’s light, airy, delicate fronds grow from tough, wiry, twinning vines that are up to 90 ft. long. These have great tensile strength and can trip up and bring down a woodland hiker all by themselves. If they were bundled together they’d make great suspension bridge cables. The vine does not die off in winter and from season to season it heaps on to itself and on to neighboring plants, native and non-native alike, to form a dense, light-blocking tangle. The plant spreads with rhizomes on the ground and also by millions of tiny spores that the wind spreads easily through the air. Land managers have sought to control the fern with fire. Unfortunately, if the vine happens to have climbed up into a tree, its mat of light, delicate, paper-like leaves creates an excellent fire ladder that can bring flame into the tree’s top, destroying it. The vine does not die in the fire and will re-grow onto the charred tree carcass.
The lesson in all this: next time you are in some far away, exotic land and some plant catches your fancy, leave it be. It’s there and not here for a reason. Please don’t experiment on your friends and neighbors or their property just because you think some plant is “pretty.” Otherwise, it may be too late.