North America Native Plant

Longsheath Panicgrass

Botanical name: Panicum longivaginatum

USDA symbol: PALO19

Life cycle: perennial

Habit: grass

Native status: Native to Hawaii  

Longsheath Panicgrass: A Critically Rare Hawaiian Treasure Worth Protecting Meet longsheath panicgrass (Panicum longivaginatum), one of Hawaii’s most endangered native grasses that’s fighting for survival in the wild. If you’re thinking about adding this unique species to your garden, hold that thought – this isn’t your typical landscaping grass, and ...

Rare plant alert!

Region: Conservation status by state

Status: S1: Status is uncertain but is somewhere between the following rankings: Critically Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 5 or fewer occurrences or very few remaining individuals (<1,000) ⚘

Longsheath Panicgrass: A Critically Rare Hawaiian Treasure Worth Protecting

Meet longsheath panicgrass (Panicum longivaginatum), one of Hawaii’s most endangered native grasses that’s fighting for survival in the wild. If you’re thinking about adding this unique species to your garden, hold that thought – this isn’t your typical landscaping grass, and here’s why.

What Makes Longsheath Panicgrass Special?

Longsheath panicgrass is a perennial grass that belongs to the Poaceae family, making it a true grass rather than a grass-like sedge or rush. As a native Hawaiian species, it evolved specifically in the unique island ecosystems of Hawaii, developing characteristics that helped it thrive in its original habitat.

Where Does It Grow?

This rare grass is endemic to Hawaii, meaning it grows naturally nowhere else on Earth. Its distribution is limited exclusively to the Hawaiian Islands, where it once played a role in native ecosystems.

The Reality Check: Why You Shouldn’t Plant This Grass

Here’s where things get serious – longsheath panicgrass has a Global Conservation Status of S1, which translates to Critically Imperiled. This means:

  • Typically only 5 or fewer populations exist in the wild
  • Fewer than 1,000 individual plants may remain
  • The species faces extreme vulnerability to extinction
  • Every remaining plant is precious for conservation efforts

Because of its critically endangered status, this grass should only be cultivated by conservation professionals, botanical gardens, or researchers working on species recovery programs. Home gardeners should avoid attempting to grow this species.

Habitat and Growing Conditions

Longsheath panicgrass has facultative wetland status in Hawaii, meaning it can grow in both wetland and non-wetland environments. However, specific growing requirements, soil preferences, and care instructions aren’t well-documented due to the species’ rarity and conservation priority.

Supporting Conservation Instead

Rather than trying to grow this endangered grass, consider these meaningful alternatives:

  • Support Hawaiian native plant conservation organizations
  • Choose other native Hawaiian grasses that aren’t critically imperiled
  • Create habitat for native species in your landscape using stable native plants
  • Learn about and advocate for endangered plant protection

The Bottom Line

Longsheath panicgrass represents the fragile beauty of Hawaii’s native flora. While we can’t grow it in our gardens, we can appreciate its role in Hawaii’s natural heritage and support conservation efforts that give this remarkable grass a fighting chance for survival. Sometimes the best way to love a plant is to protect it in its natural habitat rather than bringing it home.

If you’re passionate about Hawaiian native plants, consider working with local conservation groups or botanical gardens that might be involved in legitimate conservation efforts for this and other endangered species.

Longsheath Panicgrass

Classification

Group

Monocot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Liliopsida - Monocotyledons

Subclass

Commelinidae

Order

Cyperales

Family

Poaceae Barnhart - Grass family

Genus

Panicum L. - panicgrass

Species

Panicum longivaginatum H. St. John - longsheath panicgrass

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