Mountain Tansymustard

Mountain Tansymustard: A Rare Native Gem Worth Protecting in Your Garden

If you’re looking to add a touch of wild beauty to your garden while supporting native plant conservation, mountain tansymustard (Descurainia incana incana) might just be the perfect choice. This delicate wildflower brings both charm and ecological value to the right garden setting, though its rarity makes it a plant that deserves special consideration.

What is Mountain Tansymustard?

Mountain tansymustard is a native North American forb that can live as an annual, biennial, or perennial depending on growing conditions. As a forb, it’s a non-woody plant that puts its energy into producing lovely clusters of small flowers rather than developing thick stems or bark. Don’t let its delicate appearance fool you – this hardy little plant has adapted to some pretty challenging environments across northern and western North America.

Where Does It Naturally Grow?

This native beauty has quite an impressive range, naturally occurring across Alaska, many Canadian provinces (including Alberta, British Columbia, Manitoba, New Brunswick, Ontario, Quebec, Saskatchewan, Yukon, Northwest Territories, and Labrador), and numerous U.S. states from the northern plains to the Rocky Mountains. You’ll find it growing wild in Colorado, Idaho, Montana, Wyoming, North Dakota, South Dakota, Minnesota, and even extending into parts of Kansas, Texas, New Mexico, and northeastern states like Maine, Massachusetts, and Connecticut.

A Word of Caution: This Plant is Rare

Here’s something important every gardener should know: mountain tansymustard has a Global Conservation Status of S2, meaning it’s considered Imperiled. With typically only 6 to 20 occurrences or a few remaining individuals (1,000 to 3,000) in the wild, this plant is especially vulnerable to disappearing from its native habitats.

What does this mean for gardeners? If you want to grow mountain tansymustard, please only use responsibly sourced material from reputable native plant nurseries or seed suppliers who ethically collect from abundant populations or propagate their own stock. Never collect from wild populations.

Why Grow Mountain Tansymustard?

Despite its rarity concerns, there are compelling reasons to consider this native plant:

• Conservation impact: Growing it helps preserve genetic diversity and supports conservation efforts
• Pollinator support: The small yellow flowers attract native bees and other beneficial insects
• Low maintenance: Once established, it’s quite drought tolerant and requires minimal care
• Authentic native landscaping: Perfect for creating truly local plant communities
• Delicate beauty: Fine, feathery foliage and clusters of tiny yellow flowers add subtle charm

What Type of Garden Suits Mountain Tansymustard?

This isn’t a plant for formal flower beds or high-maintenance landscapes. Mountain tansymustard shines in:

• Wildflower meadows and prairies
• Native plant gardens
• Xerophytic (dry) gardens
• Natural area restorations
• Rock gardens with good drainage

Growing Conditions and Care

Mountain tansymustard is surprisingly adaptable, but it does have some preferences:

Sunlight: Full sun is ideal, though it can tolerate some light shade

Soil: Well-drained soils are essential – this plant doesn’t like wet feet. It adapts to various soil types but prefers moderately fertile to lean soils

Water: Drought tolerant once established, but benefits from occasional watering during extended dry periods

Hardiness: Extremely cold hardy, suitable for USDA zones 2-7

Planting and Care Tips

Growing mountain tansymustard successfully is mostly about getting the conditions right:

• Start from seed: This is typically the most available and sustainable option
• Plant in fall: Many seeds benefit from cold stratification over winter
• Don’t overwater: Good drainage is crucial – soggy soil can kill this plant
• Allow self-seeding: The plant may naturally reseed in suitable conditions
• Minimal fertilization: Too much fertilizer can actually harm native plants like this one

The Bottom Line

Mountain tansymustard offers gardeners a chance to grow something truly special – a rare native plant that supports local ecosystems while adding subtle beauty to naturalized gardens. However, its imperiled status means this isn’t a plant to grow casually. If you choose to include it in your garden, you’re taking on a small but meaningful role in conservation.

Remember: only source this plant responsibly, provide the well-drained conditions it needs, and enjoy knowing you’re helping preserve a piece of North America’s natural heritage right in your own backyard.