3,800m
3,100m
2,400m
1,700m
1,000m

lupine.day

An Interactive Guide to Alpine Wildflowers

Species Identification

Lupinus polyphyllus

Large-leaved Lupine

A robust perennial reaching up to 1.5m in height, known for its dense flower racemes in shades of blue, purple, and pink. Native to western North America, now widespread across temperate alpine meadows.

Altitude 800–2,600m Bloom Jun–Aug Height 0.6–1.5m

Lupinus perennis

Sundial Lupine

A graceful perennial with palmately compound leaves arranged in a sundial pattern. Bears beautiful pink-to-lavender flower spikes. Critical host plant for the endangered Karner blue butterfly across eastern meadows.

Altitude 200–1,800m Bloom May–Jul Height 0.3–0.6m

Lupinus texensis

Texas Bluebonnet

The iconic state flower of Texas. A compact annual forming dense carpets of vivid blue across prairie hillsides each spring. Distinguished by its bright white-tipped banner petal and sweet fragrance.

Altitude 100–900m Bloom Mar–May Height 0.2–0.4m

Flower Anatomy

Banner Petal (Standard) Wing Petal Keel Calyx Palmate Leaf Stem (Peduncle)

Lupine Flower Structure

The lupine flower displays the classic papilionaceous (butterfly-like) form characteristic of the Fabaceae family. Each individual floret on the raceme comprises five petals arranged in a distinctive bilateral symmetry.

1
Banner Petal

The largest, uppermost petal that reflexes backward, serving as a visual signal to pollinators. Often features a contrasting color spot that changes from white to magenta after pollination.

2
Wing Petals

Two lateral petals flanking the keel. They function as landing platforms for bees and enclose the reproductive structures within.

3
Keel

Two fused lower petals forming a boat-shaped structure that houses the stamens and pistil. Presses down under bee weight to dust the visitor with pollen.

Ecology Dashboard

1

Soil pH Preferences

Acidic (4.5–5.5)
Optimal
Slightly Acidic (5.5–6.5)
Good
Neutral (6.5–7.0)
Marginal
Alkaline (7.0+)
Poor

Lupines thrive in acidic, well-drained soils. Their nitrogen-fixing root nodules allow colonization of nutrient-poor substrates.

2

Pollinator Relationships

Bumblebees (Bombus spp.) are the primary pollinators, heavy enough to depress the keel and access nectar. The flower's trip mechanism ensures efficient pollen transfer.

3

Altitude Distribution

2,400m 3,200m Primary Lupine Zone

Most lupine species concentrate between 1,500m and 3,000m elevation, in the subalpine and alpine meadow zones where competition from trees is reduced.

4

Growth Cycle

Germination Bloom Seed Set Dormancy Annual Cycle

Most lupine species complete their lifecycle in a single growing season, with seeds requiring cold stratification to break dormancy the following spring.

The Summit

You have ascended from the valley floor through the meadows, studied the intricate anatomy of each floret, and explored the ecological web that sustains these remarkable plants. Lupines are more than wildflowers -- they are ecosystem engineers, fixing atmospheric nitrogen into impoverished soils, providing critical habitat for endangered butterflies, and painting entire mountainsides in waves of violet and blue each spring.