PlantFiles: Southern Sword Fern, Narrow Swordfern, Erect Sword Fern, Ladder Fern, Tuber Fern
Nephrolepis cordifolia

This is just about the most invasive plant I have ever introduced into my garden. It knows no limits (except it will burn back in hot, direct sunlight). It will bulldoze away any plants in its path as it spreads. Further research needs to be done, I think, to determine if the plant roots have an allelopathic ability to kill other plants. I greatly regret that I ever planted it, but I did so when I was more of a newbie gardener.

This plant is sometimes confused with Boston Fern (Nephrolepis exaltata 'Bostoniensis'). In fact, some unscrupulous or uninformed plant nurseries will actually be selling N. cordifolia in hanging baskets labeled as "Boston Fern" when the plant is actually Sword Fern. There are several botanical differences between the leaf structure of the two ferns, but the differences are generally so small that only a trained eye would recognize one from the other. However, one glaring difference makes it easy to tell them apart. The N. cordifolia (invasive Sword Fern) has spherical tubers on the roots; N. exaltata 'Bostoniensis' does not have these round tubers. Before buying anything labeled as "Boston Fern," I would recommend lifting the fern from its pot or hanging basket in order to inspect the roots to see if the round tubers are present. If the round tubers are there, the plant is most likely Sword Fern and is being misrepresented as Boston Fern.

This link will take you to the University of Florida IFAS document which gives further clues on how to distinguish native Florida ferns from non-native ferns: [HYPERLINK@edis.ifas.ufl.edu]

Jeremy

Yes Palmbob, this is the one. In North Carolina and other southern states large hanging baskets of this are coveted by many for hang outside on big porches and displayed on pedistals. It is hard for most to keep it looking good, but they try.
Here in Florida it's everywhere, making a soft edge to everyones gardens. I yank out a bushel everytime I go outside to work. It has little "cocktail onion" at it's base from which small hair like roots grow from and establish it shallowly in the sand. This pulls up easily, but also grows back when you turn around.
When we have a freeze it does insulate some of the other plants just by it's dense precence.
This is on Florida's invasive plant list. I can mark it negative, but that because it is impossible to be rid of it here.

I have grown sword ferns several times.. very hardy here in hot, dry southern CAlifornia... and quite invasive... though have to admit pretty easy to yank out of the ground. Not sure how it does in other climates, but always looks sad after Santa Anas, and winter... half to all the stems die leaving a bunch of sticks as the new ferns come up... makes a messy, unattractive look and requires a lot of work to get things looking nice again.

My question is really is THIS the species I am dealing with, or is it the Polystichium? I think it's this one, but could be wrong. It is grown very commonly down here and sold all over as an indoor as well as an outdoor fern. Spreads like wild fire... this the right one?

Tufts of finely toothed sword-shaped fronds rise from short, erect, hairy leaf stems. It will grow to 2-3 feet tall. The spores are visible on the underside of the leaf, but this fern mainly propagates by spreading hairy runners. It does best in shade but will take sun if given ample water.

I have lived in zone 9b for 22 years and gardened here for most of those years. Erect sword fern can be seen many, many places doing quite nicely. It is considered invasive by some, and when put in the wrong place it certainly can be. You can mow it occasionally without harm to the plants, and it is a dependable ground cover in shade here, wherever there is woodsy soil. The more rich the soil, the more lush the ferns and the farther they'll run.

I like this plant. I have yet to release it in my new garden, because I know what it is capable of. But I will, because I know what it does for woodland settings.