North America Native Plant

Bartram’s Orthotrichum Moss

Botanical name: Orthotrichum bartramii

USDA symbol: ORBA7

Habit: nonvascular

Native status: Native to North America  

Bartram’s Orthotrichum Moss: A Tiny Marvel for Your Garden Meet Bartram’s orthotrichum moss (Orthotrichum bartramii), a delightful little bryophyte that’s quietly making gardens across North America more beautiful, one tiny cushion at a time. While you might not have heard of this particular moss before, it’s been carpeting rocks and ...

Rare plant alert!

Region: Conservation status by state

Status: S2S4: Status is uncertain but is somewhere between the following rankings: Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000) ⚘ Apparently Secure: Uncommon but not rare, and usually widespread. Possibly cause for longterm concern. Typically more than 100 occurrences in the state or more than 10,000 individuals ⚘

Bartram’s Orthotrichum Moss: A Tiny Marvel for Your Garden

Meet Bartram’s orthotrichum moss (Orthotrichum bartramii), a delightful little bryophyte that’s quietly making gardens across North America more beautiful, one tiny cushion at a time. While you might not have heard of this particular moss before, it’s been carpeting rocks and tree bark in our native landscapes for ages, and it just might be the low-maintenance groundcover you never knew you needed.

What Exactly Is Bartram’s Orthotrichum Moss?

This charming moss belongs to the bryophyte family – those ancient, rootless plants that were among Earth’s first land colonizers. Unlike the typical lawn moss you might be familiar with, Orthotrichum bartramii is what botanists call an epiphytic or epilithic moss, meaning it loves to make its home on solid surfaces like tree bark, rocks, and fallen logs rather than soil.

The moss forms small, dense cushions that rarely grow taller than an inch or two. What makes it particularly interesting are its distinctive spore capsules, which appear seasonally and add textural interest to its already appealing form.

Where You’ll Find It Growing Wild

As a North American native, Bartram’s orthotrichum moss has established itself throughout much of the eastern and central regions of the continent. You’re most likely to spot it in temperate woodlands, where it thrives in the dappled light filtering through tree canopies.

Is It Good for Your Garden?

Absolutely! Here’s why this little moss deserves a spot in your landscape:

  • Zero maintenance: Once established, it requires virtually no care
  • Natural moisture retention: Helps keep surrounding soil damp
  • Erosion control: Stabilizes soil on slopes and around trees
  • Wildlife habitat: Provides shelter for tiny beneficial insects
  • Year-round interest: Stays green through most seasons

Perfect Spots in Your Landscape

Bartram’s orthotrichum moss works beautifully in several garden settings:

  • Woodland gardens and shade borders
  • Rock gardens and stone walls
  • Around the base of mature trees
  • Japanese-style gardens for authentic texture
  • Rain gardens and naturalized areas

How to Identify Bartram’s Orthotrichum Moss

Spotting this moss in the wild (or confirming what’s already growing in your garden) is easier than you might think:

  • Growth pattern: Forms small, compact cushions or mats
  • Color: Bright to dark green, sometimes with a yellowish tint
  • Habitat: Look on tree bark, rocks, or old wood
  • Size: Individual cushions typically 1-3 inches across
  • Capsules: Small, oval-shaped spore containers when present

Growing Conditions and Care

The beauty of working with native mosses like Bartram’s orthotrichum is their adaptability to local conditions. This species thrives in:

  • Light: Partial to full shade
  • Moisture: Consistent humidity, but not waterlogged conditions
  • pH: Slightly acidic conditions (typical of woodland environments)
  • Temperature: Hardy in USDA zones 3-9

A Word About Conservation

While Bartram’s orthotrichum moss isn’t considered rare everywhere it grows, its conservation status varies by region. If you’re interested in introducing it to your garden, the best approach is to create conditions where it might naturally establish itself rather than harvesting from wild populations. Patient gardeners often find that simply maintaining the right moisture and light conditions will eventually attract native mosses to settle in on their own.

The Bottom Line

Bartram’s orthotrichum moss might not be the showiest plant in your garden, but it’s certainly one of the most reliable and eco-friendly. Whether it appears on its own or you encourage its presence, this little moss brings authentic North American character to any shaded corner of your landscape. Plus, there’s something deeply satisfying about supporting a plant that’s been thriving in our ecosystems for millions of years – talk about time-tested garden performance!

Bartram’s Orthotrichum Moss

Classification

Group

Moss

Kingdom

Plantae - Plants

Subkingdom
Superdivision
Division

Bryophyta - Mosses

Subdivision

Musci

Class

Bryopsida - True mosses

Subclass

Bryidae

Order

Orthotrichales

Family

Orthotrichaceae Arn.

Genus

Orthotrichum Hedw. - orthotrichum moss

Species

Orthotrichum bartramii R.S. Williams - Bartram's orthotrichum moss

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