Psoralea pinnata (Blue butterfly-bush)
Botanical name: Psoralea pinnata
Common names: Blue butterfly-bush, Blue Pea
Family: Fabaceae
Subfamily: Faboideae
Origin: Southern Africa
USDA Zone: 8-10
Plant form: Large bush
Mature height: 5-10 ft
Sun exposure: Full sun or bright light indoor; semi-shade
Cold tolerance: Tolerates light freezing to about 30°F for short periods (mature plants). Young plants must be protected.
Watering: Regular
Flower color: Blue, lavender, purple
Suitable for: Outdoors in the suitable USDA zone; small gardens, containers, and indoor growing
Fragrance: Fragrant; perfume plant
Flood tolerance: High
Wildlife: Attracts butterflies and hummingbirds
Invasive: Can spread quickly, needs controlNative to Southern Africa, Psoralea pinnata, otherwise known as the blue butterfly-bush, is a large shrub that can grow up to 5 to 10 feet tall. It thrives in full sun to semi-shade, with regular watering. The delicate, fragrant lavender and purple flowers that the bush produces attract butterflies and hummingbirds. Although the plant is invasive, it is also a mature plant that is cold hardy at least down to 30s F for a short period of time, and is flood tolerant. This makes it relatively easy to grow in USDA zones 8 -10.
When it comes to growing the blue butterfly-bush in a pot, it should be noted that it can be done in colder regions provided certain conditions are met. The soil should be moist at all times and the pot should be placed in a sheltered spot to prevent frost damage. A good winter mulch will also help to insulate the roots and keep them warm. If you are living in an area with cold winters, it may be best to bring the pot indoors for the duration of the winter season. By following these tips, you can be sure to enjoy the beauty of the blue butterfly-bush all year round!
