Indigo bush, false indigo, or Amorpha fruticosa is a native plant to most the United States and a portion of Canada. Its large geographic range hints at its adaptability and tenacity for growth which, consequently, makes this plant an ideal choice for a myriad of different landscape conditions. Amorpha fruticosa gets its common name from the indigo colored conical flowers which smell like vanilla. Its typical bloom-time spans from April to June. While it tends to grow in wetter more riparian environments, it has the ability to be drought tolerant once established. Amorpha fruticosa thrives in USDA zones 4-9 and grows successfully in sun to dappled shade. It is said to be immune to insects and pests while tolerating nutrient deficient soils. Additionally, it has been noted to grow in acidic to alkaline soils. The culmination of these characteristics make this an ideal native plant for the Southwest landscape.
With a growth habit of 4 to 6 feet tall, ability to handle windy conditions, and hold soil in place with its extensive root system, the Amorpha fruticosa is a successful plant for erosion control and an excellent plant for windbreaks. Beyond its capacity to preserve and shelter from the elements, this plant has the capacity to fix nitrogen because of its membership in the Fabaceae or pea family. The root system develops symbiotic nodules that help the plant to uptake nitrogen from the soil for its own growth as well as enhancing the bioavailablity of nitrogen to other surrounding plants.
For those interested in attracting and promoting pollinators in the garden, the Amorpha fruticosa is also known as a host plant for many native species of butterfly and is pollinated by native bees. With its ability to tolerate and thrive in a variety of settings, fix nitrogen in poor soils, and provide food for native insects makes the Amorpha Fruticosa a Southwest garden superstar and a must-have addition to any garden or landscape.
Melissa Koch – Ecoscapes Landscape Maintenance supervisor