Lemon Button Fern, Button Sword Fern, Fishbone Fern
Nephrolepis cordifolia 'Duffii'
The Lemon Button Fern is the little sibling of the Boston Fern, and it’s literally as cute as a button (sorry). Named for its small, round leaves and the unique lemony aroma that’s released when they’re crushed. I’d encourage you to try it but I can’t condone you hurting your poor plant… Thankfully, its otherwise hardy nature and forgiving temperament make it a great fit for terrariums of all kinds. Nephrolepis cordifolia ‘Duffii’ is incredibly easy cultivar to look after, and shouldn’t grow beyond 12′ tall. Though, it’s easily trimmed and propagated if it does get unruly!
At a Glance
Where to Buy Lemon Button Fern
See the links below to purchase from reputable terrarium plant shops and marketplaces (may include affiliate links).
Terrarium Plant Guide
Nephrolepis cordifolia 'Duffii' Care & Growth
The Lemon Button Fern will thrive under most typical terrarium settings. It prefers bright, indirect light but isn’t too demanding for a fern.
Nephrolepis cordifolia ‘Duffii’ will grow best with regular, even moisture. Though, as you might imagine for a fern native to Australia, it’s actually pretty drought resistant. It should have no problems adapting to any healthy terrarium water cycle.
This tropical fern likes constant moisture, but doesn’t do well if buried in a soggy substrate. Nephrolepis cordifolia ‘Duffii’ grows shallow but dense roots, so it’s important to pick a nutrient rich substrate that retains moisture, but also drains well.
Temperature & Humidity
True to its Australian origins, the Lemon Button Fern prefers to grow in a hot and humid environment. Though it’ll tolerate a wide range of conditions for a fern.
‘Duffii’ is a dwarf variety of Nephrolepis cordifolia, and the fact that they rarely grows taller than a foot high makes them a great fern choice for most terrariums. Their long, thin “Fishbone” fronds are full of round, finely-toothed leaves. The leaves themselves are a wonderful yellow-green colour that complement the “Lemon” in their name.
The easiest way to propagate a Lemon Button Fern is to trim off any baby ferns that sprout from the “runners”. You’ll easily identify the runners if you see them, long tendrils that “run” from the base of the fern. You can also separate any rooted rhizome sections from a suitably mature plant.
Varieties & Similar Plants
Nephrolepis cordifolia is closely related to the popular Boston Fern houseplant Nephrolepis exaltata. Though N.cordifolia itself doesn’t seem to have any other popular cultivars beyond ‘Duffii’.
If your Lemon Button Fern is showing brown fronds, there’s a good chance that your humidity levels are too low. If this happens, it’s best to simply remove any dead or damaged fronds. The plant will easily regenerate even if aggressively trimmed back. Also, when planting, take care not to bury the crown of the fern along with the rhizomes or you’ll risk crown rot.