My Staghorn Fern Is Pregnant!

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Well, not exactly pregnant, of course. That’s not really a botanical term. But it is bearing spores for the first time. And I’m so proud of it! 

One of the fronds began showing an unusual pale green growth on its underside last spring, at each of its tips. This “growth” is a mass of sporanges, special structures that produce spores. Over time, they’ve turned a sort of beigey-brown, a sign the spores are mature or nearly mature. It’s these spores that, like seeds, give life to new staghorn ferns.

My Staghorn’s Story

Mine started out as a small houseplant in a 4-inch (10-cm) pot 5 years ago. Platycerium bifurcatum: it’s the common staghorn fern of commerce. At first, it only had gray-green, outward-stretching fronds (the ones that look like stag or moose antlers), the so-called fertile fronds, although actually few of them ever produce spores, but soon it started producing cup-shaped, leathery, pale green fronds at the base that soon enough turned brown: shield fronds, also called sterile fronds.

These brown shield fronds aren’t dead, they’ve just stopped photosynthesizing. If ever you try to remove one, you’ll see: under its dry-looking exterior, you’ll find it’s still fleshy and alive. In the wild, the cup-shaped sterile fronds help this epiphytic (tree-growing) fern to cling to its host and catch the dead leaves and other debris that, when they decompose, are the fern’s source of minerals. That makes it a so-called trash-basket plant.

In the second year, I moved the fern to its current home, a hanging basket. This is to imitate, somewhat, its tree-growing natural lifestyle. I’d call the staghorn fern’s growth “slow but steady.” You’d swear it isn’t growing at all, but in fact, it slowly fills in, produces more fronds, both fertile ones (green) and shield fronds (green, but soon turning brown). In fact, my fern now entirely covers the pot’s surface. 

I no longer water my staghorn fern in the traditional fashion. I can’t even see or touch the potting mix now: it’s completely engulfed in shield fronds. It would be hard to know where to pour the water! Instead, I soak it. Once every two weeks (unlike most ferns, it doesn’t mind drying out), I take it down and lower the pot into a bucket of tepid water, letting it soak for 10 to 20 minutes. Theoretically, I could add fertilizer to the water. I never have and it doesn’t seem to care. On more than one occasion, I’ve forgotten it and left it soaking overnight: it doesn’t seem to mind that either. Afterwards, I lift it up (it becomes surprisingly heavy: there’s a lot of moisture stored in all those fronds!), let it drain a bit, then hang it back up. 

During the summer, I hang it outside in a tree. I give it no special summer care: I don’t even water. I let it do what it does in the wild: catch rainfall when there is any and, when not, absorb morning dew as well as humidity from the air. In late summer, before the nights become too cool, I bring it back in, clean it up a bit, and hang it back in my greenhouse and start soaking it biweekly again.

Unfernlike Behavior

You’ll note that I don’t treat my staghorn fern like a fern, that is, carefully keep it moist, provide plenty of humidity and protect it from the full power of the sun. I treat it more like a succulent, supplying as much sun as I can indoors and, as mentioned, watering infrequently, only when it’s quite dry. But that’s the way it grows in the wild, exposed to bright light, including plenty of full tropical sun, and coping with the irregularity of natural rainfall. In most climates where this widely distributed fern grows (P. bifurcatum is native to Indonesia, New Guinea and Australia), it goes through a distinct dry season with little or no rain. I don’t try to imitate that. I figure its summer outside, with very irregular rainfall, counts as a dry season.

Babies to Come?

Now that there is a fertile frond (yes, just one), I wonder if baby ferns will pop up among my other plants. I often do find sporelings (baby ferns of other species) in pots where I never planted them. Spores are light and easily carried in the air. They seem to mostly show up in pots where I’m starting cuttings or sowing seeds and that I’ve slipped inside a clear plastic bag to keep extra humid. That might be too humid for Platycerium spores. But we’ll see.

The absolutely coolest thing would be if one germinated on the stem of one of my houseplants (I have several you could call indoor trees), as they do in the wild. But only time will tell: I don’t even know if the spores are mature yet!

Still, isn’t it fascinating to see what our “ordinary” houseplants do sometimes! They certainly do make life interesting!