Summer lupine
Lupinus formosus · Fabaceae
📷 "All photos were taken by staff of the NRCS California Plant Materials Center, 2009-2010, except where noted." · Public domain
⚠️ Chiens/chats : graines et feuilles toxiques par ingestion, troubles digestifs graves. Humains : graines toxiques par ingestion, alcaloïdes toxiques.
The gardener's calendar
Ideal time to plant summer lupine: set it out when the soil is neither frozen nor waterlogged, and water generously as it establishes.
ID card
- Foliage
- Deciduous
- Blooming
- May to July
- Adult size
- 60 cm in height
- Growth
- Fast
- Hardiness
- Moderate to good (zones 6-9)
- Origin
- California (United States)
- Soil type
- Well-drained, slightly acidic
✓ Taxonomy verifiedSource: AI estimate · hardiness: reliability medium.
Expert tips
The key tip
Lupinus formosus needs well-draining soil rich in organic matter. Its large seeds germinate better after scarification or soaking for 24 hours before sowing.
The common mistake
Sowing seeds directly without preparation and in compacted soil: poor germination, weak seedlings, sparse or absent flowering in the first year.
The pro's trick
Lightly scarify seeds with sandpaper, soak for 24 hours, then sow in pots in October.
Care
Light exposure
Elegant lupine thrives in full sun, requiring at least 6 hours of direct light daily for abundant flowering. A south or west-facing exposure is ideal. In very hot regions, light afternoon shade can prevent excessive drying.
Watering
Water moderately and regularly during spring growth and flowering. Keep the soil moist but not waterlogged, as lupines fear stagnant moisture. Reduce watering after flowering and in winter.
Soil
Plant it in well-drained, slightly acidic to neutral soil. Improve heavy soil with sand and compost to prevent root suffocation. Lupines tolerate poor soils but appreciate an aerated structure.
Fertilizing
A balanced fertilizer application in spring is generally sufficient. Avoid excess nitrogen, which would stimulate foliage at the expense of flowering. A flowering plant fertilizer can support flower production early in the season.
Pruning and cleanup
Remove spent flowers regularly to encourage a second flush of blooms. At season's end, cut back stems after frost or when foliage dries. Fall cleanup limits fungal diseases.
Diseases and pests
Watch for powdery mildew in case of excessive humidity and poor air circulation. Aphids may occasionally colonize young shoots. Good drainage and adequate aeration generally prevent major problems.
Did you know?
Elegant lupine is part of California's rich flora and appeared in botanical paintings by 19th-century explorers. Its genus name, Lupinus, derives from the Latin 'lupus' (wolf), as it was once believed the plant depleted soils—a misconception, since lupines, like all legumes, actually enrich the soil with nitrogen through bacterial fixation.
Where to buy it
Plant in spring or early autumn, avoiding spells of intense heat. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, April, May, September.
Add this plant to my garden →Plants from the same family
- Chinese wisteriaWisteria sinensis
- Common broomCytisus scoparius
- Black locustRobinia pseudoacacia
- Common PeaLathyrus oleraceus
- Honey locustGleditsia triacanthos
- Hairy greenweedGenista pilosa
Tips generated and checked by Viridia — adapt them to your local climate.