Native to New Zealand, Pellaea rotundifolia is a beautifully delicate little terrarium fern. With soft, button-shaped leaves along the lengths of its (relatively short) fronds, it’s a wonderful addition to terrariums of all sizes. In fact, this is one of the few truly compact fern species, maxing out at around 12 inches tall.
The deep green leaves will naturally darken as the plant matures, and though red stem development can be caused by heat/light stress with some species, with this plant it’s entirely natural. In fact, the entire plant can darken as the plant ages and that’s reflected in the genus name Pellaea, coming from the Greek word for “dark”.
At a Glance
Where to Buy the Button Fern
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Terrarium Plant Guide
Button Fern Care & Growth
As with most ferns, the button fern will do best with bright, indirect lighting. Harsh direct sunlight will quickly scorch the delicate leaves.
For a fern, Pellaea rotundifolia has surprisingly light watering requirements. It’ll still appreciate regular moisture as long as it’s light and even, but it’ll rapidly deteriorate if oversaturated.
Paired with its low water requirements is a tendency for Pellaea rotundifolia to rapidly rot if left in a soggy substrate – so excellent drainage is vital in keeping this fern healthy and happy.
A coarser substrate mix with orchid bark or sand would help, or you can supplement with the likes of perlite.
Temperature & Humidity
Though Pellaea rotundifolia is sometimes grown as a houseplant, it thrives in warm and humid terrarium environments.
This fern is a relatively slow grower, and remains a very compact plant even when mature. The fronds have a slight arching growth pattern which makes them great for planting in a higher spot in a terrarium.
As with many other ferns, propagating the button fern through division is pretty easy. As long as each rhizome division has a handful of fronds and a healthy root system, they should easily settle when replanted separately into the substrate.
Varieties & Similar Plants
As far as I can tell, Pellaea rotundifolia appears to be the only commercially available variety in the genus. Though there are other Pellaea species native to Australia and New Zealand such as Pellaea falcata which is called the sickle fern for its long, sickle shaped pinnae.
Pellaea rotundifolia is often confused for the lemon button fern (Nephrolepis cordifolia ‘Duffii’) with their long fronds and button shaped leaves, but they’re very different ferns.
Arguably the biggest challenge in growing this species of fern in a terrarium is getting the right level of moisture. It’s not crazy sensitive to overwatering, but it’s definitely less tolerant of saturated substrates when compared to other ferns. Look out for yellowing and wilting fronds as signs of distress.
I’d try pairing with other more drought tolerant species (e.g. arrowhead vines) rather than typical water loving tropical plants.
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