Human predation is probably the last thing threatening the existence of ferns on the planet. Few ferns are edible, let alone palatable.

The bracken fern (Pteridium aquilinum), after a great deal of processing to leach out carcinogenic compounds is one example of the reason why we don’t eat so many ferns.
But in Japan where there is a distinct name for ferns that are edible, warabi, bracken fern is actually quite popular. At a truck stop between Fukushima City and Sendai we saw them processes and packaged for sale. The day before I had eaten them in a bowl of Udon soup with mountain vegetables. I had nibbled on raw bracken in my own garden back home; it was acrid and tasted carcinogenic. The processed bracken in my soup was delicious, a subtle asparagus/spinach flavor, definitely wild but also in some sense a refined flavor.
If any of you have ever battled bracken in your garden, you know that eating it would probably not keep this cosmopolitan fern, which could easily be called an aggressive weed, in check. As a Northwest gardener it is hard to imagine any fern as anything less than weedy. Sword ferns (Polystichum munitum) and lady ferns (Athyrium filix-femina) like to move into any shady, or not so shady, nook in our gardens. They even end up in unlikely places: a mossy roof or a crevice in black top.
It is truly hard to think of ferns as threatened, but like many other plants and animals on this planet habitat loss is reducing populations of the rarer and less aggressive of the ferns. And though some of those were the exact ferns we sought out on this trip, they will not be the subject of this post, but the next. What I want to talk about now is the ferns that survive us, or even flourish in man-made habitats.
Many ferns are amazingly adaptable not requiring the warm humid climate of the early Carboniferous Era in which they developed and dominated, nor a Victorian terrarium for their survival. If I took anything away from this trip it was the knowledge that ferns weren’t an idea that nature had some 300 million years ago and abandoned. They are not only primordial survivors that managed to stay alive through the rise of flowering plants. Ferns have been evolving all along; we are still finding interspecific hybrids today, proof of their continual development. Ferns are as modern as roses in some sense, but with a longer period of time to develop some amazing survival strategies.

The ladder fern (Nephrolepis cordifolia) made it on to our list but was regarded, or not regarded at all, by the experts on our trip because of it’s weedy and downright invasive habit. Nearly every palm in the Kii Penninsula was covered with this fern. Here you can see it taking over a storefront in Shingu; it didn’t even seem like there was any soil for it to grow in.

The closely related Boston fern (N. exaltata) seems to care little about where it grows, either. Here under an escalator in a department store basement in Tokyo one thrived in a pot, far from rain showers or sunlight. I’ve seen this fern forming thick masses on the Big Island of Hawaii, unstoppable in that ideal climate.

Or here growing under fluorescent light in one of Taro Okamoto’s expressive planters on exhibit in the Tokyo museum in his honor.

I was actually surprised how often I saw ferns deep in the interior spaces of stores, some even subterranean, one would never think of as supporting plant life.

The ubiquitous squirrel’s foot fern (Davallia mariessii) another native fern of Japan, could be found for sale everywhere from the gift shop In Bandai Asahi National Park…

and at the Tokyo Antique Fair in Ginza…

and seen on every doorstep from Sendai to Shingu.

It even graced the flag that our guide in the Kii Penninsula, Oohara-san, used to rally the pteridological troops each morning, and to signal our return to the bus at the end of the day.

Another ubiquitously planted, though not native, fern was the epiphytic bird’s nest fern (Asplenium nidus).

Here it is hard to tell if it had naturalized into this wall at the Konouchi Shrine in Mie Prefecture, or if it was planted; it’s architectural presence defied the wildness of the place, at the same time feeling totally harmonious with the temple architecture.

In the village of Iseki outside Shingu ,I was struck by this planting using the native gemmiferous spikemoss (Selaginella moellendorfii) with non-native bird’s nest fern and other garden plants.

The apotheosis of the bird’s nest fern is it’s many wavy leafed cultivars; this is probably ‘Victoria’. Brought in from a grower in a tropical locale, I wondered how long it would last in this underground train station flower shop in Tokyo. It was only $45 for this large, nearly 3-foot, beautiful fern.

What amazed me most was not so much the environments into which we have dragged ferns, like this staghorn fern ( Platycerium sp.) tied to the side of a building in the hyper-urban district of Tokyo called Ginza.

But the places ferns follow us willingly, like this man-made “canyon” near Yoyogi Park in Tokyo. In some ways it is the exactly like the environments we sought out in the country to look for rare native ferns.

These urban ferns are seldom native. Actually this Tokyo wall is nearly covered with the exotic and often cultivates ribbon fern (Pteris cretica).

Or a mix of natives and invasives, as in this channel in the city of Shingu.
Our guide called it the shortest river in Japan; I don’t know if she was joking or telling us the truth.

I have the feeling this is probably a native fern, though I had neither the time nor inclination to identify it, swept up in the bustle of Tokyo.

The forward thinking architects, inspired by the adaptability of ferns to urban environments and their propensity for growing on vertical surfaces, used many Japanese native ferns in this planting on an upscale men’s clothing store façade in Sendai.

As were the architects who designed this ferny façade in the Kanda neighborhood of Tokyo.

or whoever made this dramatic window treatment and filled it with plastic plants, including ferns.

Ferns are such a beloved garden element that even the laziest of gardeners “grow” them. The gardener who created this “planting” of plastic plants in the Akihabara neighborhood of Tokyo included many ferns. After all, this garden was in the shadows of an overhead freeway and high-rise buildings along a major 6-lane thoroughfare. Maybe he had his doubts that real ferns would make it, though I wouldn’t.

It was our love of ferns, among other plants, that spawned the development of the glass greenhouse. To this day we create them all over the world for growing plants that cannot endure the local climate. In Shinjuku Gyoen, the National Garden of Japan in Tokyo, this new and sculpturally beautiful greenhouse has impressive displays of exotic ferns, that would never last outdoors even in the apparently fern friendly climate of that mega-city.

The tropical diamond maidenhair fern (Adiatum trapezoidiforme).

The elk horn fern (Polypodium punctatum ‘Grandiceps’).

and Nephrolepis exaltata ‘Fluffy Ruffles’ all grow to luxurious dimensions in this ideal manmade environment.

Koisikawa Botanical Garden at the University of Tokyo hosts a lovely collection of hardy ferns in a crude cinderblock lath house.

The beds are nicely labeled for boning up on Japans native ferns.

Others are planted out in the rows in the open garden, and may have been aprt of the medicinal garden. I couldn’t read the signs.

All of this is a testament to the fact that we humans have a great interest in ferns and that we will go to great lengths to cultivate them and enjoy their beauty, to seek them out in their native habitats and study them…

Still, it was big news in Wakayama prefecture when a group of foreigners showed up in this out of the way part of Japan to look at ferns. Oohara-san says in the article that he hopes that local people will understand the importance not only of the ferns in this area but plants in general and the necessity for preserving them.