North America Native Plant

Three-rib Arrowgrass

Botanical name: Triglochin striata

USDA symbol: TRST16

Life cycle: perennial

Habit: grass

Native status: Native to the lower 48 states  

Synonyms: Triglochin striatum Ruiz & Pav., orth. var. (TRST6)   

Three-Rib Arrowgrass: A Native Wetland Wonder for Water-Loving Gardens If you’ve been searching for a native plant that thrives in those perpetually soggy spots in your yard, let me introduce you to three-rib arrowgrass (Triglochin striata). This unassuming perennial might not win any beauty contests, but it’s an absolute champion ...

Three-Rib Arrowgrass: A Native Wetland Wonder for Water-Loving Gardens

If you’ve been searching for a native plant that thrives in those perpetually soggy spots in your yard, let me introduce you to three-rib arrowgrass (Triglochin striata). This unassuming perennial might not win any beauty contests, but it’s an absolute champion when it comes to loving wet feet and supporting native ecosystems.

What Exactly Is Three-Rib Arrowgrass?

Three-rib arrowgrass is a native perennial grass-like plant that belongs to the arrow-grass family (Juncaginaceae). Don’t let the name fool you—it’s not actually a true grass, but it sure looks like one with its slender, linear leaves and modest appearance. This hardy native has been quietly doing its job in America’s wetlands for centuries, and it’s about time more gardeners discovered its potential.

Where Does It Call Home?

This wetland warrior has quite an impressive native range across the United States. You’ll find three-rib arrowgrass naturally growing in twelve states spanning both coasts:

  • Eastern states: Alabama, Delaware, Florida, Georgia, Louisiana, Maryland, Mississippi, North Carolina, South Carolina, and Virginia
  • Western states: California and Oregon

The plant thrives in USDA hardiness zones 8-10, making it perfect for gardeners in warmer climates with consistent moisture.

Why You Might Want This Wetland Wonder

Here’s the thing about three-rib arrowgrass—it’s not going to be the star of your flower border, but it absolutely shines in the right conditions. This plant is classified as an obligate wetland species, which means it almost always occurs in wetlands. If you have a consistently wet area in your landscape that other plants struggle with, this native beauty might be your solution.

Three-rib arrowgrass works wonderfully in:

  • Rain gardens and bioswales
  • Bog gardens and wetland restorations
  • Coastal plantings where salt tolerance is needed
  • Naturalized wet meadows
  • Pond edges and stream banks

Growing Conditions That Make It Happy

The secret to success with three-rib arrowgrass is understanding that it’s essentially aquatic in its preferences. This plant wants:

  • Moisture: Consistently wet to saturated soil—think squishy underfoot wet
  • Sun exposure: Full sun to partial shade
  • Soil type: Tolerates various soil types as long as they stay moist
  • Salt tolerance: Can handle coastal conditions and some salinity

Planting and Care Tips

The good news about three-rib arrowgrass is that once you get it established in the right spot, it’s remarkably low-maintenance. Here’s how to set it up for success:

Planting: Plant in early spring or fall when temperatures are moderate. Make sure your planting site stays consistently moist—if it ever dries out completely, your arrowgrass won’t be happy.

Establishment: During the first growing season, monitor moisture levels carefully. The plant should establish relatively quickly in proper wetland conditions.

Maintenance: Once established, three-rib arrowgrass is virtually maintenance-free. You can cut it back in late winter if desired, but it’s not necessary.

What About Wildlife Benefits?

While three-rib arrowgrass is wind-pollinated and doesn’t attract butterflies like flashier native plants, it does provide valuable habitat structure in wetland ecosystems. The dense growth can offer shelter for small wildlife and contributes to the overall health of wetland plant communities.

The Bottom Line

Three-rib arrowgrass isn’t for everyone, and that’s perfectly okay. But if you have a wet area that needs a native solution, or if you’re working on wetland restoration, this humble native deserves serious consideration. It’s the kind of plant that quietly does its job without demanding attention—sometimes that’s exactly what a landscape needs.

Just remember: this is a plant for wet conditions only. If you’re looking for something for average garden conditions, you’ll want to explore other native options. But for those soggy spots where other plants struggle, three-rib arrowgrass might just be the perfect fit.

Wetland Status

The rule of seasoned gardeners and landscapers is to choose the "right plant for the right place" matching plants to their ideal growing conditions, so they'll thrive with less work and fewer inputs. But the simplicity of this catchphrase conceals how tricky plant selection is. While tags list watering requirements, there's more to the story.

Knowing a plant's wetland status can simplify the process by revealing the interaction between plants, water, and soil. Surprisingly, many popular landscape plants are wetland species! And what may be a wetland plant in one area, in another it might thrive in drier conditions. Also, it helps you make smarter gardening choices and grow healthy plants with less care and feeding, saving you time, frustration, and money while producing an attractive garden with greater ecological benefits.

Regions
Status
Moisture Conditions

Arid West

OBL

Obligate Wetland - Plants with this status almost always occurs in wetlands

Atlantic and Gulf Coastal Plain

OBL

Obligate Wetland - Plants with this status almost always occurs in wetlands

Western Mountains, Valleys, and Coast

OBL

Obligate Wetland - Plants with this status almost always occurs in wetlands

Three-rib Arrowgrass

Classification

Group

Monocot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Liliopsida - Monocotyledons

Subclass

Alismatidae

Order

Najadales

Family

Juncaginaceae Rich. - Arrow-grass family

Genus

Triglochin L. - arrowgrass

Species

Triglochin striata Ruiz & Pav. - three-rib arrowgrass

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