North America Non-native Plant

Diplazium Maximum

Botanical name: Diplazium maximum

USDA symbol: DIMA71

Native status: Not native but doesn't reproduce and persist in the wild

Synonyms: Athyrium maximum (D. Don) Milde (ATMA11)   

Diplazium maximum: The Mystery Fern Worth Getting to Know Ever stumbled across a plant name that makes you scratch your head? Meet Diplazium maximum, a fern that’s more enigmatic than your average garden variety plant. While this species doesn’t roll off the tongue with a catchy common name, it belongs ...

Diplazium maximum: The Mystery Fern Worth Getting to Know

Ever stumbled across a plant name that makes you scratch your head? Meet Diplazium maximum, a fern that’s more enigmatic than your average garden variety plant. While this species doesn’t roll off the tongue with a catchy common name, it belongs to a fascinating group of ferns that deserves a closer look.

What Exactly Is Diplazium maximum?

Diplazium maximum is a member of the fern family, scientifically classified within the genus Diplazium. You might occasionally see it referenced by its synonym, Athyrium maximum, which gives us a clue about its botanical relationships. Like all ferns, this species reproduces through spores rather than flowers or seeds, making it quite different from the flowering plants that typically dominate our garden conversations.

The Geographic Mystery

Here’s where things get interesting (and a bit frustrating for plant enthusiasts): the exact native range and distribution of Diplazium maximum remains somewhat unclear in readily available horticultural sources. This isn’t uncommon with lesser-known fern species, especially those that might be limited to specific tropical or subtropical regions.

Could This Fern Benefit Your Garden?

While we don’t have extensive documentation about Diplazium maximum’s specific garden performance, ferns in the Diplazium genus generally offer several potential benefits:

  • They typically thrive in shaded areas where many flowering plants struggle
  • Most species prefer moist conditions, making them potentially useful for challenging wet spots
  • Ferns add textural interest and a lush, woodland feel to landscape designs
  • They’re generally low-maintenance once established in suitable conditions

Identification Tips

Identifying Diplazium maximum can be tricky without more specific documentation, but members of the Diplazium genus typically share certain characteristics:

  • Delicate, often pinnately compound fronds (leaves)
  • Sori (spore-bearing structures) arranged in lines along the leaf veins
  • Generally prefer shaded, moist environments
  • Deciduous or semi-evergreen growth patterns depending on climate

The Bottom Line for Gardeners

If you’re considering adding Diplazium maximum to your garden, you’ll want to do some detective work first. Given the limited readily available information about this specific species, it would be wise to:

  • Consult with local native plant societies or botanical experts
  • Verify its native status in your region before planting
  • Consider well-documented native fern alternatives if you’re looking for reliable garden performers
  • Source any plants responsibly from reputable nurseries

While the mystery surrounding Diplazium maximum makes it intriguing, sometimes the best garden choices are the plants we know will thrive in our specific conditions. If you’re drawn to ferns, consider exploring other Diplazium species or related ferns with better-documented garden performance in your area.

Remember, the world of ferns is vast and varied – there’s likely a perfect fern match for your garden space, even if this particular species remains a bit of an enigma!

Diplazium Maximum

Classification

Group

Fern

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision
Division

Pteridophyta - Ferns

Subdivision
Class

Filicopsida

Subclass
Order

Polypodiales

Family

Dryopteridaceae Herter - Wood Fern family

Genus

Diplazium Sw. - twinsorus fern

Species

Diplazium maximum (D. Don) C. Chr. [excluded]

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