Lupin

Lupinus polyphyllus

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verifiedReviewed by the GreenScout Team

Lupins are tall, stately perennials with striking spires of densely-packed flowers in rich jewel tones and pastels. They have distinctive palmate foliage and are nitrogen-fixing plants that improve soil fertility naturally. These dramatic blooms are magnificent in cottage gardens and cut flower arrangements.

Common Problems

Select the problem your Lupin is experiencing to get a treatment guide.

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Root Rotchevron_right

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Yellow Leaveschevron_right

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Wiltingchevron_right

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Powdery Mildewchevron_right

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Underwateringchevron_right

Care Guide

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Light

Full sun to partial shade (minimum 5–6 hours sun daily) for robust growth.

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Water

Water regularly to keep soil consistently moist; good drainage is critical. Drought-sensitive; mulch to retain moisture.

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Soil

Prefers slightly acidic to neutral soil (pH 6.0–7.0). Must have excellent drainage; tolerates poor soil.

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Fertiliser

Light feeding; excess nitrogen promotes foliage at expense of flowers. Avoid high-phosphorus fertilizers.

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Temperature

Prefers cool conditions (50–70°F); struggles in hot, humid climates. Hardy to zone 3.

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Humidity

Moderate humidity preferred; excellent air circulation essential to prevent root rot and fungal disease.

Toxicity

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All parts contain quinolizidine alkaloids; toxic to cats, dogs, and children. Keep away from pets and small children.

Common Diseases

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Common Pests

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Seasonal Care

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Resume regular watering and feeding as growth picks up.

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Peak growing season. Water and feed regularly.

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Reduce watering as growth slows. Stop heavy feeding.

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Minimal watering and feeding. Protect from frost if needed.

Frequently Asked Questions

Why is Lupin good for improving my soil?

It's a nitrogen-fixing plant that naturally improves soil fertility — its roots host bacteria that convert atmospheric nitrogen into a form other plants can use.

Is Lupin safe to plant where pets roam?

No — all parts contain quinolizidine alkaloids that are toxic to cats, dogs, and children, so keep it away from pets and small children despite its garden appeal.