Lupin
Lupinus polyphyllus
Lupin is a striking perennial bearing tall, dense spikes of pea-like flowers in vivid colors above palmate leaves. A legume, it fixes nitrogen and is a cottage-garden showstopper.
- Light
- Full sun to light shade
- Water
- Moderate; well-drained soil
- Difficulty
- Moderate
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Overview
Lupin (Lupinus polyphyllus, and the popular Russell hybrids derived from it) is a clump-forming perennial legume famous for bold, candle-like flower spikes in blue, purple, pink, red, yellow, white and bicolors. The distinctive hand-shaped leaves are attractive in their own right.
As a member of the pea family, lupin fixes atmospheric nitrogen through root nodules, improving soil. It blooms in early summer and is a centerpiece of cottage and cool-climate gardens.
How to identify it
The palmate leaves and tall flower spikes are unmistakable.
- Flowers: pea-like blooms densely packed on erect spikes 1-2 ft long; wide color range including bicolors
- Leaves: palmately compound, with 9-17 leaflets radiating from a central point like fingers; often hold dewdrops attractively
- Habit: bushy clumps typically 2-4 ft tall
- Seed pods: hairy pea-like pods that dry and split, ejecting seeds
Care & growing
Lupins prefer cool summers and resent disturbance.
- Light: full sun to light shade
- Water: moderate and even; they dislike both drought and waterlogging
- Soil: light, well-drained, slightly acidic soil; they dislike heavy clay and high lime
- Temperature: hardy in cool climates (zones 4-8); struggle in hot, humid summers
- Feeding: minimal; being a legume, it needs little nitrogen
- Maintenance: deadhead spent spikes for possible rebloom
- Propagation: from seed (scarify or soak) or basal cuttings; taproot makes division difficult
Habitat & origin
Lupinus polyphyllus is native to western North America, where it grows in moist meadows, streamsides and roadsides. The garden Russell lupins were bred from it and related species.
Lupins thrive in cool, temperate climates and have naturalized in parts of Europe, New Zealand and elsewhere. They are popular in cottage gardens and cool-summer regions but short-lived in hot climates.
Uses & benefits
Lupin is grown mainly as an ornamental, with agricultural relatives.
- Garden design: a dramatic early-summer accent for borders and cottage gardens
- Soil improvement: as a nitrogen-fixing legume, lupins enrich soil and some species are grown as green manure or forage
- Ecological: flowers attract bees; foliage hosts specialist insects in native ranges
- Caution: most ornamental lupins contain toxic alkaloids, especially in the seeds; do not eat them (edible 'lupini beans' come from specially processed, low-alkaloid species)
Frequently asked questions
Why don't my lupins survive hot summers?
Lupins are adapted to cool climates and are short-lived where summers are hot and humid. Provide good drainage, light afternoon shade, and grow fresh plants from seed.
Can I eat lupin seeds?
Not garden lupins. Their seeds contain toxic alkaloids. Edible lupini beans come from specific low-alkaloid species and require careful soaking to remove bitterness.
Should I deadhead lupins?
Yes. Removing the main spike after it fades can encourage smaller secondary blooms and prevents excessive self-seeding.
Do lupins improve the soil?
Yes. As legumes, they fix nitrogen through root nodules, so they need little feeding and can benefit surrounding soil.
Lupin guides
In-depth guides for identifying, growing, and caring for Lupin.
