Update: I assumed that my new ferns were "Western" sword ferns which is the variety that I wanted to plant and the ones that are native to my area. When I read the sticker on the side of the pots, I learned that they are "Southern" sword ferns (Nephrolepis cordifolia) which are considered an invasive plant.

I decided to plant half of them in my front yard flower beds which were recently covered with landscape fabric and bark mulch. I grouped them together in one section and will keep a close eye on them. I hope that I will not regret doing this. I'll plant the other half in pots until I see how "invasive" the first group are. I will be paying a lot more attention the next time I purchase plants.

Nephrolepis cordifolia definitely has a confusing name history, so I can understand how this could happen. It seems to have a ton of common names (and/or is confused with other ferns) including Boston fern, Erect Sword fern, Ladder fern, Narrow Swordfern, Southern Sword fern, Sword fern, Tuber fern, Tuber Ladder fern, Tuber Sword fern, Tuberous Sword fern, Fishbone fern, and Herringbone fern.

Nephrolepis cordifolia could be a problem to native vegetation (and wildlife) if you're in Florida. The Florida Exotic Pest Plant Council lists Nephrolepis cordifolia as one of the invasive exotics "which are altering native plant communities by displacing native species, changing community structures or ecological functions, or hybridizing with natives."

But since Western swordfern (Polystichum munitum) is native to your area, I'm assuming you're in California. If so, Nephrolepis cordifolia may be less invasive in your area, since it's a tropical fern. If you decide to keep the Nephrolepis cordifolia, and it doesn't survive the winter there, you can always replace it with a Polystichum munitum.

If you want to purchase Polystichum munitum and you're in California, you can ask the California Native Plant Society (see link below) for a supplier near you where you can purchase it.

Here is a link that might be useful: California Native Plant Society

My yard was half covered with an "invasive" sword fern. I pull it up where I don't want it and plant it where I do. We are getting along quite well. Because of its invasive qualities, it is easy to grow and requires little attention. Also, it's free in that I always have some that can be moved elsewhere. If it gets a little out of hand, it's still more attractive than just about anything else that is overgrown.