Bigleaf Lupine
Lupinus polyphyllus · Big-leaved Lupine · Garden Lupin · Large-leaved Lupine · Many-leaved LupineUSDA | Grow Zone
3-7Outdoors all year in zones 3 to 7. Anywhere colder, keep it as a houseplant. Protect it below 32°F.
- Light
- Full sun, 6-8 hours
- Water
- Deeply once a week
- Humidity
- 40-60%
- Temperature
- 60-75°F
- Difficulty
- Intermediate
- Growth
- Moderate
- Mature size
- 2-4 ft tall, 1-3 ft wide
- Pets
- Toxic to cats and dogs
Lupinus polyphyllus, commonly known as Bigleaf Lupine, is a stunning perennial native to North America. Its vibrant flowers and attractive foliage make it a popular choice for gardens, attracting pollinators and adding color to landscapes.
Ask Vesper about Bigleaf Lupine
Ideal temperature
60-75°F is where it grows fastest. Below 32°F cold damage starts.
Spacing and harvest
- Mature size
- 2-4 ft tall, 1-3 ft wide
- Plant apart
- 12-24 in
- Frost
- Half hardy: light frost only
Everything it needs
9 essentials at a glance
Watering
Lupinus polyphyllus prefers consistently moist soil, especially during its growing season in spring and summer.
Water deeply once a week, allowing the top inch of soil to dry out between waterings. In hot, dry conditions, increase frequency to twice a week. Signs of over-watering include yellowing leaves and root rot, while under-watering may cause wilting and leaf drop.
Light
This plant thrives in full sun, requiring at least 6-8 hours of direct sunlight daily.
It can tolerate partial shade, especially in hotter climates, but may produce fewer flowers. Ideal placement is in a location that receives morning sun and afternoon shade during peak summer heat.
Soil
Lupinus polyphyllus prefers well-draining soil rich in organic matter, with a pH range of 6.0 to 7.0.
A recommended potting mix includes equal parts of peat moss, compost, and perlite to ensure good drainage and aeration.
Humidity
This plant enjoys moderate humidity levels, ideally between 40-60%.
To increase humidity, consider misting the leaves or placing a humidity tray filled with water and pebbles nearby. Signs of humidity stress include browning leaf tips and curling leaves.
Temperature
Lupinus polyphyllus thrives in temperatures between 60-75°F (15-24°C) and is hardy in USDA zones 3-7.
It can tolerate light frost but may struggle in extreme heat, so provide some shade during the hottest months.
Fertilizing
Use a balanced fertilizer with an NPK ratio of 10-10-10, applying it every 4-6 weeks during the growing season.
Reduce fertilization in the fall and winter. Signs of nutrient deficiency include stunted growth, pale leaves, and poor flowering.
Pruning
Prune Lupinus polyphyllus in early spring to remove any dead or damaged stems.
Use clean, sharp pruning shears to make clean cuts just above a leaf node. Deadheading spent flowers encourages further blooming and maintains a tidy appearance.
Repotting
Repotting is necessary every 2-3 years or when the plant becomes root-bound.
Choose a pot that is 1-2 inches larger in diameter than the current one. Signs it needs repotting include roots growing out of the drainage holes and stunted growth. To repot, gently remove the plant from its pot, loosen the roots, and place it in fresh potting mix.
Propagation
Propagation can be done through seeds or division.
For seeds, soak them in water for 24 hours before planting in spring, about 1 inch deep in well-draining soil. For division, carefully separate established clumps in early spring or fall, ensuring each division has roots and shoots. Replant immediately.
When it's unhappy
Yellow leaves
Why it happens
This can be caused by over-watering or nutrient deficiency.
How to fix it
Adjust watering practices and consider fertilizing with a balanced fertilizer.
Root rot
Why it happens
Overly wet soil and poor drainage can lead to root rot.
How to fix it
Ensure proper drainage and reduce watering frequency. Remove affected roots and repot in fresh soil.
Wilting leaves
Why it happens
Under-watering or extreme heat can cause wilting.
How to fix it
Check soil moisture and water thoroughly if dry. Provide shade during the hottest part of the day.
Poor flowering
Why it happens
Insufficient sunlight or nutrient deficiency can lead to fewer flowers.
How to fix it
Ensure the plant receives full sun and consider fertilizing to boost nutrient levels.
Browning leaf tips
Why it happens
Low humidity or over-fertilization can cause browning.
How to fix it
Increase humidity levels and reduce fertilizer application.
Care through the year
Spring
In spring, prune any dead stems and apply a balanced fertilizer to encourage growth. Water regularly as the plant begins to actively grow.
Summer
During summer, ensure consistent watering, especially in hot weather. Deadhead spent flowers to promote continuous blooming.
Fall
In fall, reduce watering as the plant enters dormancy. Consider mulching around the base to protect roots from frost.
Winter
In winter, protect the plant from extreme cold by covering it with mulch. Avoid watering unless the soil is excessively dry.
Toxicity & Safety
Lupinus polyphyllus is considered toxic to pets, particularly dogs and cats, as well as children. The seeds and leaves contain alkaloids that can cause gastrointestinal distress, including vomiting and diarrhea, if ingested.
Good to know
How often should I water my Bigleaf Lupine?
Water your Bigleaf Lupine once a week, ensuring the soil is consistently moist but not soggy. In hot weather, you may need to water twice a week.
Why are my Big-leaved Lupine leaves turning yellow?
Yellow leaves may indicate over-watering or a nutrient deficiency. Check your watering schedule and consider applying a balanced fertilizer.
What type of soil is best for Garden Lupin?
Garden Lupin thrives in well-draining soil rich in organic matter, with a pH between 6.0 and 7.0. A mix of peat moss, compost, and perlite works well.
Can I grow Many-leaved Lupine in partial shade?
Yes, Many-leaved Lupine can tolerate partial shade, but it will produce fewer flowers. Full sun is ideal for optimal growth and blooming.
When is the best time to prune Large-leaved Lupine?
Prune Large-leaved Lupine in early spring to remove dead or damaged stems and encourage new growth. Deadheading spent flowers throughout the blooming season is also beneficial.
Is Bigleaf Lupine toxic to pets?
Yes, Bigleaf Lupine is toxic to pets, particularly dogs and cats, as well as children. The seeds and leaves can cause gastrointestinal issues if ingested.
How do I propagate Garden Lupin?
You can propagate Garden Lupin through seeds or division. Soak seeds for 24 hours before planting or divide established clumps in spring or fall.
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