PURPLE ROBE LOCUST

Plant Name: Thornless Purple Robe Locust
Scientific Name: Robinia × ambigua ‘Purple Robe’ — Purple Robe Locust, Purple Robe Black Locust
Mature Height: 30–40 ft
Mature Spread: 20–30 ft
Growth Rate: Fast (2–3 ft/year)
Sun: Full sun
Water: Low to moderate; 5–10 gal per watering while establishing, 2–3 times/week during hot, dry weather; 10–20 gal per watering once established during extended dry periods
Foliage: Blue-green, pinnate compound leaves; deciduous
Fall Color: Yellow to yellow-green
Flower Color: Deep rose-purple to pinkish-purple, fragrant, pea-like flowers
Bloom Time: Late spring to early summer
Fruit: Flat brown seed pods; production varies
Hardiness Zones: 4–8 (−30°F to 20°F)
Features: Thornless; fragrant purple flowers; fast-growing; drought tolerant once established; attractive open canopy; excellent flowering shade tree
Additional Facts: Purple Robe Locust is a fast-growing hybrid locust selected for its showy purple flowers and thornless stems. It performs well in full sun and is tolerant of heat, drought, and poor soils once established.