North America Native Plant

Spleenwort

Botanical name: Asplenium ×inexpectatum

USDA symbol: ASIN10

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: ×Asplenosorus inexpectatus E.L. Braun ex Friesner (ASIN21)   

The Elusive Spleenwort: A Rare Native Fern You’ll Probably Never Find Ever heard of Asplenium ×inexpectatum? Don’t worry if you haven’t—this little spleenwort is one of nature’s best-kept secrets, and for good reason. This rare native fern is so uncommon that finding one in the wild would be like discovering ...

The Elusive Spleenwort: A Rare Native Fern You’ll Probably Never Find

Ever heard of Asplenium ×inexpectatum? Don’t worry if you haven’t—this little spleenwort is one of nature’s best-kept secrets, and for good reason. This rare native fern is so uncommon that finding one in the wild would be like discovering a botanical unicorn in your backyard.

What Makes This Spleenwort So Special?

The spleenwort known as Asplenium ×inexpectatum is what botanists call a hybrid fern—notice that little × in its name? That’s your clue that this plant is the result of two different Asplenium species getting together and creating something entirely new. It’s a perennial fern that, once established, comes back year after year with fresh, delicate fronds.

You might also see this fern listed under its synonym ×Asplenosorus inexpectatus, but don’t let the name shuffle confuse you—it’s the same elusive plant.

Where in the World Can You Find It?

Here’s where things get really interesting (and a bit disappointing for most of us): this native spleenwort has been documented in only one state—Ohio. That’s right, just Ohio. While it’s technically native to the lower 48 states, its distribution is so incredibly limited that most native plant enthusiasts will never encounter one in person.

Why You Probably Shouldn’t Try to Grow It

Before you start scouring nurseries for this rare beauty, let’s talk reality. The extreme rarity of Asplenium ×inexpectatum means several things:

  • It’s virtually impossible to find in commercial cultivation
  • Wild collection would be environmentally irresponsible
  • Its specific growing requirements are not well-documented
  • It likely needs very particular conditions to thrive

This fern’s rarity suggests it has very specific habitat needs that are difficult to replicate in typical garden settings. As a responsible gardener, it’s best to admire this botanical rarity from afar and focus on more readily available native alternatives.

Better Alternatives for Your Native Fern Garden

If you’re drawn to the idea of growing native spleenworts, consider these more common and garden-friendly alternatives:

  • Maidenhair Spleenwort (Asplenium trichomanes) – widely available and adaptable
  • Ebony Spleenwort (Asplenium platyneuron) – striking dark stems and reliable growth
  • Christmas Fern (Polystichum acrostichoides) – evergreen and virtually indestructible
  • Lady Fern (Athyrium filix-femina) – graceful and easy to grow

The Role of Rare Plants in Conservation

While you might not be able to grow Asplenium ×inexpectatum in your garden, its existence reminds us of the incredible diversity hidden in our native landscapes. These rare species often serve as indicators of healthy ecosystems and may play important roles we don’t yet fully understand.

Rather than trying to obtain this rarity, consider supporting conservation efforts in Ohio and other states that protect the unique habitats where such specialized plants can survive and thrive.

Creating Habitat for Common Native Ferns

Even though this particular spleenwort isn’t practical for home cultivation, you can still create wonderful fern gardens using more common native species. Most native ferns prefer:

  • Partial to full shade
  • Moist, well-draining soil rich in organic matter
  • Protection from strong winds
  • Consistent moisture without waterlogging

By creating these conditions, you’ll not only have a beautiful, low-maintenance garden feature but also provide habitat for the small creatures that depend on native ferns for shelter and food.

So while Asplenium ×inexpectatum might remain a botanical mystery for most of us, there’s a whole world of wonderful, accessible native ferns waiting to transform your shady spots into lush, green retreats.

Spleenwort

Classification

Group

Fern

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision
Division

Pteridophyta - Ferns

Subdivision
Class

Filicopsida

Subclass
Order

Polypodiales

Family

Aspleniaceae Newman - Spleenwort family

Genus

Asplenium L. - spleenwort

Species

Asplenium ×inexpectatum (E.L. Braun ex Friesner) Morton [rhizophyllum × ruta-muraria] - spleenwort

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA