A tough, dependable fern

Nephrolepis cordifolia, Southern Sword Fern, at the De Young Museum in San FranciscoTough and dependable might seem unusual adjectives to use when describing a fern, but this guy’s adaptability is almost legendary. Because it can take such a large amount of abuse, it is often subjected to same, looking worse for wear by hanging on none-the-less.

Given half a chance, Nephrolepis cordifolia, Erect Sword Fern, will reward you with its handsome, 2-3ft (60-90cm) foliage and ask for little in return.

The upright nature of the fronds also makes a nice compliment with modern architecture (here it is against the wall of the new De Young Museum in San Francisco). I’ve often planted them en masse in rectilinear beds bordered by a patio or an impenetrable edging, which they fill over time.

There is a handsome cultivar called ‘Lemon Buttons’, whose leaflets are very short and almost round. Its overall height is shorter, reaching about 1ft (30cm). ‘Duffy’ is another dwarf cultivar.

An occasional topdressing of compost and trimming of older, untidy fronds will keep a patch of fernyness going strong year after year.

Curiously, the actual origin of this species is uncertain, and is considered ‘pantropical.’ This species is occasionally listed as invasive in wetter, more humid climates (but not recorded as invasive in summer dry mediterranean regions). In the US, it is specifically causing a problem in Hawaii, Florida, and southern counties of Georgia and Alabama, which is spreads rapidly, becoming intertwined or even displacing other understory plants. It is confused with the Florida native species, Nephrolepis exaltata, which it greatly resembles. Identification by laymen is easily made by examining the rhizomes – N. cordifolia has small, round tubers and its Floridian cousin does not.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: