Trianglelobe Moonwort: A Rare and Mysterious Native Fern Worth Protecting
Meet the trianglelobe moonwort (Botrychium ascendens), one of nature’s most elusive and fascinating native ferns. This isn’t your typical garden-variety fern that you’ll find at the local nursery—it’s a rare treasure that most gardeners will never encounter, and that’s exactly why it deserves our attention and protection.
What Makes This Fern Special?
The trianglelobe moonwort is a small, perennial fern that belongs to the unique moonwort family. Unlike the lush, feathery ferns you might picture, this little guy is surprisingly modest in appearance. It typically produces just two parts: a triangular sterile frond (the leafy part) and a separate fertile spike that releases spores. The whole plant rarely exceeds 6 inches in height, making it easy to overlook in its natural habitat.
What’s truly remarkable about this fern is its rarity. With a Global Conservation Status of S3 (Vulnerable), the trianglelobe moonwort is considered vulnerable throughout its range, with typically only 21 to 100 known occurrences containing between 3,000 and 10,000 individuals total.
Where Does It Call Home?
This hardy little fern is native to northern North America, including Alaska, Canada, and the northern United States. You can find it growing naturally in Alberta, British Columbia, Alaska, California, Ontario, Quebec, Yukon, Idaho, Minnesota, Montana, Nevada, Oregon, Washington, and Wyoming. It’s perfectly adapted to cool climates and can handle the harsh conditions of USDA hardiness zones 2-6.
A Fern of Many Habitats
One of the most interesting things about the trianglelobe moonwort is its flexibility when it comes to moisture levels. Depending on the region, it can be found in:
- Non-wetland areas (most commonly)
- Wetland edges and margins
- Grassy meadows and openings
- Open woodlands with dappled shade
This adaptability has helped it survive in diverse environments across its northern range, though it still remains quite rare overall.
Should You Try to Grow It in Your Garden?
Here’s where we need to have an honest conversation. While the trianglelobe moonwort is undeniably fascinating, it’s not really a plant for home cultivation—and that’s actually a good thing for its conservation. Here’s why:
Rarity Concerns: With its vulnerable status, removing these ferns from wild populations could harm already fragile ecosystems. If you’re lucky enough to spot one in the wild, the best thing you can do is observe and photograph it, then report your sighting to local botanists or conservation groups.
Cultivation Challenges: Like many moonworts, this species has complex ecological requirements, including specific mycorrhizal fungal relationships that are nearly impossible to replicate in garden settings. Even experienced fern growers find moonworts extremely challenging to establish and maintain.
How to Identify Trianglelobe Moonwort
If you’re hiking or exploring natural areas within its range, keep an eye out for these identifying features:
- Small size (usually under 6 inches tall)
- Single triangular sterile frond with a distinct three-part division
- Separate fertile spike rising above the sterile frond
- Often found in small colonies or scattered individuals
- Emerges in late spring to early summer
Supporting Conservation Efforts
The best way to grow your appreciation for the trianglelobe moonwort is to support its conservation in the wild. Consider:
- Participating in citizen science projects that track rare plant populations
- Supporting habitat conservation in areas where it naturally occurs
- Choosing other native ferns for your garden that aren’t at risk
- Learning to identify and report sightings to help researchers understand its distribution
Native Alternatives for Your Garden
If the mysterious beauty of native ferns appeals to you, consider these more garden-friendly alternatives that won’t impact wild populations:
- Christmas fern (Polystichum acrostichoides)
- Lady fern (Athyrium filix-femina)
- Maidenhair fern (Adiantum pedatum)
- Ostrich fern (Matteuccia struthiopteris)
The trianglelobe moonwort may not be destined for your garden bed, but it serves as a wonderful reminder of the incredible diversity and complexity of our native plant communities. Sometimes the greatest gift we can give a rare plant is simply leaving it alone to thrive in its natural habitat—and that’s a pretty special kind of gardening philosophy, don’t you think?
