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THERMOPSIS montana

Image of Thermopsis montana

TL

Family

Fabaceae

Botanical Name

THERMOPSIS montana

Plant Common Name

Mountain False Lupine, Mountain Goldenbanner

Special Notice

This entry has yet to be reviewed and approved by L2G editors.

General Description

Growing quickly once winter snows melt away, the mountain false lupine finally starts its yellow flower display anytime from early to midsummer. This clump-forming herbaceous perennial grows from spreading rhizome roots. It's native to the high elevation, moist woodland openings and meadows from southeastern British Columbia to northern New Mexico across the Rocky Mountains.

The slender stems may be purplish with a white, hairy overcast. A leaf comprises three green leaflets, with two tiny leaf-like stipules. Depending on climate and elevation, stem tips produce an upright cluster-spike of yellow blossoms in very late spring to midsummer. The pea-like flowers have clawed petals and attract bees. The straight, upright-held seed pods are flat and velvety, covered in sparse, silvery hairs and contain white seeds.

Grow mountain false lupine in full to partial sun in a well-drained soil that's rather sandy or gritty. In more fertile soils, the growth is faster and lusher, and many more seedlings germinate on their own. If summers are too hot or dry, the foliage looks peaked after flowering ends. Use this wildflower in an open meadow, rocky hillside or in a mixed border. Propagate by seed, or cautiously divide clumps. Plants resent root disturbance and will be never slow to recover after transplanting.

The similar-looking prairie false lupine (T. divaricarpa), shares much of the same native range but grows in drier, more alkaline, sandier soils. It also is more abundant in exposed grassland sites, whereas the mountain false lupine is often seen growing at the sun-lit bases of aspen trees and in meadows.

Characteristics

  • AHS Heat Zone

    8 - 1

  • USDA Hardiness Zone

    3 - 8

  • Sunset Zone

    A2, A3, 1a, 1b, 2a, 2b, 3a, 3b, 4, 5, 6, 7, 11, 14, 15, 16, 17

  • Plant Type

    Perennial

  • Sun Exposure

    Full Sun, Partial Sun, Partial Shade

  • Height

    16"-36" / 40.6cm - 91.4cm (20)

  • Width

    12"-26" / 30.5cm - 66.0cm

  • Bloom Time

    Late Spring, Early Summer, Summer

  • Native To

    Western United States, Northwestern United States, Southwestern United States, Canada

Growing Conditions

  • Soil pH

    Acidic, Neutral, Alkaline

  • Soil Drainage

    Well Drained

  • Soil type

    Loam, Sand

  • Growth Rate

    Medium

  • Water Requirements

    Drought Tolerant, Average Water

  • Habit

    Clump-Forming

  • Seasonal Interest

    Summer

Ornamental Features

  • Flower Interest

    Showy

  • Flower Color

    Yellow

  • Fruit Color

    Tan

  • Foliage Color (Spring)

    Green, Light Green

  • Foliage Color (Summer)

    Green, Light Green

  • Foliage Color (Fall)

    Light Green, Yellow Green

  • Fragrant Flowers

    No

  • Fragrant Fruit

    No

  • Fragrant Foliage

    No

  • Bark or Stem Fragrant

    No

  • Flower Petal Number

    Single

  • Repeat Bloomer

    No

  • Showy Fruit

    No

  • Edible Fruit

    No

  • Showy Foliage

    Yes

  • Foliage Texture

    Medium

  • Foliage Sheen

    Matte

  • Evergreen

    No

  • Showy Bark

    No

Special Characteristics

  • Usage

    Alpine, Mixed Border, Rock Garden / Wall, Wildflower

  • Sharp or Has Thorns

    No

  • Invasive

    No

  • Self-Sowing

    Yes