North America Native Plant

Smith’s Buckthorn

Botanical name: Rhamnus smithii

USDA symbol: RHSM

Life cycle: perennial

Habit: shrub

Native status: Native to the lower 48 states  

Synonyms: Rhamnus smithii Greene ssp. typica C.B. Wolf (RHSMT)   

Smith’s Buckthorn: A Hidden Gem for Rocky Mountain Gardens If you’re looking for a native shrub that’s as tough as the Rocky Mountains themselves, let me introduce you to Smith’s buckthorn (Rhamnus smithii). This unassuming little shrub might not win any beauty contests, but it’s got the kind of quiet ...

Smith’s Buckthorn: A Hidden Gem for Rocky Mountain Gardens

If you’re looking for a native shrub that’s as tough as the Rocky Mountains themselves, let me introduce you to Smith’s buckthorn (Rhamnus smithii). This unassuming little shrub might not win any beauty contests, but it’s got the kind of quiet charm and resilience that makes it a fantastic choice for gardeners who appreciate plants that actually belong in their landscape.

What Exactly Is Smith’s Buckthorn?

Smith’s buckthorn is a perennial shrub that typically grows as a multi-stemmed woody plant, usually staying under 13-16 feet tall – though most specimens you’ll encounter are much more modest in size. Think of it as the strong, silent type of the plant world. It’s native to the lower 48 states, specifically calling Colorado and New Mexico home.

Where You’ll Find This Rocky Mountain Native

This buckthorn species has a pretty specific address – it’s naturally found growing in Colorado and New Mexico, where it has adapted to life in montane and subalpine environments. If you live in these areas, you’re looking at a plant that’s been thriving in your climate for thousands of years.

Why Consider Smith’s Buckthorn for Your Garden?

Here’s where Smith’s buckthorn really shines – it’s the definition of low-maintenance gardening. Once established, this shrub is remarkably drought tolerant and can handle the kind of challenging conditions that make other plants throw in the trowel.

The Good Stuff:

  • Native to Colorado and New Mexico – it belongs here
  • Extremely low water needs once established
  • Provides habitat and food for local wildlife
  • Small flowers offer nectar for pollinators
  • Produces berries that wildlife appreciate
  • Tough enough for xeriscaping projects

The Honest Truth:

  • Not a showstopper in terms of ornamental appeal
  • Limited geographic range – only suitable for specific regions
  • Can be difficult to find in nurseries

Growing Conditions and Care

Smith’s buckthorn is hardy in USDA zones 4-7, which makes sense given its mountain origins. This shrub prefers well-draining soil and can handle everything from full sun to partial shade – though it seems happiest with plenty of sunshine.

The beauty of this plant lies in its simplicity. Once you get it established (which might take a season or two), it’s remarkably self-sufficient. It’s adapted to the feast-or-famine water cycles of its native habitat, so it can handle dry spells like a champ.

Planting and Care Tips

Getting Smith’s buckthorn started in your garden is straightforward, though patience is your friend here:

  • Plant in spring or fall when temperatures are moderate
  • Choose a spot with good drainage – soggy soil is this plant’s kryptonite
  • Water regularly the first year to help establish roots
  • After establishment, water deeply but infrequently
  • Prune in late winter if you need to shape it or remove dead wood
  • Mulch around the base to retain moisture and suppress weeds

Perfect Garden Scenarios

Smith’s buckthorn isn’t for every garden, but in the right setting, it’s perfect. Consider it for:

  • Native plant gardens focused on Colorado/New Mexico species
  • Wildlife habitat areas
  • Xeriscaping projects
  • Naturalistic landscapes
  • Erosion control on slopes
  • Low-maintenance areas where you want something native

The Wildlife Connection

While Smith’s buckthorn might not be the flashiest plant in your garden, local wildlife definitely appreciates it. The small flowers provide nectar for various pollinators, and the berries that follow (which change from red to black as they ripen) offer food for birds and small mammals.

Should You Grow Smith’s Buckthorn?

If you’re gardening in Colorado or New Mexico and you’re looking for a truly native, low-maintenance shrub that supports local wildlife, Smith’s buckthorn deserves a spot on your consideration list. It’s not going to be the star of your garden’s show, but it’ll be the reliable supporting actor that makes everything else look good.

The main challenge you’ll face is actually finding this plant in nurseries, since it’s not commonly cultivated. You might need to seek out specialty native plant nurseries or consider growing it from seed if you can source it responsibly.

For gardeners outside of Colorado and New Mexico, this probably isn’t the plant for you – stick with native species from your own region instead. But if you’re lucky enough to live where Smith’s buckthorn naturally occurs, you’ve got the opportunity to grow a piece of authentic Rocky Mountain flora right in your backyard.

Smith’s Buckthorn

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Rosidae

Order

Rhamnales

Family

Rhamnaceae Juss. - Buckthorn family

Genus

Rhamnus L. - buckthorn

Species

Rhamnus smithii Greene - Smith's buckthorn

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