In my front garden I've let a planting bed become overrun with what looks like an innocent fern. However, on closer inspection it is the unruly counterfeit of our native sword fern (Nephrolepis exaltata).
So I wanted to remove it. This nonnative species (Nephrolepis cordifolia) is a fast grower on its own rhizome, as well as spreading by spores. And it is easily confused with the native sword fern, as they are extremely similar in habit and appearance.
There are two factors that distinguish the nonnative sword fern from the native:
1. Observing the root system may be the quickest way to make a positive identification. The nonnative variety often (but not always) produces tubers. If tubers are present, it is unquestionably the nonnative sword fern, often referred to as Boston fern.
2. Look at the back of the fronds. In the nonnative sword fern, the membrane that holds the spores on the back of the frond is crescent- to kidney-shape (as shown) compared with a more rounded or horseshoe shape in the native.
Removing it by hand is fairly easy in our sandy soil. Just reach down to the base, grasp all the fronds of each plant and pull it out, roots and all.