Purple Robe Locust

Robinia pseudoacacia 'Purple Robe'

Light

Water

Moderate water in Phoenix. Water deeply and regularly during establishment; once established, allow the upper soil to dry between deep irrigations. Provide supplemental water during prolonged summer heat.

Size

30-40 ft tall × 20-30 ft wide

Habit

Upright tree – single-trunk

Toxicity

Toxic — Pets & Livestock

Description

Purple Robe locust (Robinia ‘Purple Robe’) is a fast-growing shade tree with fragrant, purple-pink flower clusters and airy, compound foliage. It can grow in Phoenix, but extreme summer heat and reflected sun can stress it.

Bloom Time

Spring (April-May)

Deciduous / Evergreen

Deciduous

Special Features

Attracts Bees / Pollinators, Drought Tolerant, Fragrant

Growth Rate

Moderate to fast

Growth Habit

Upright tree – single-trunk

Mature Size

30-40 ft tall × 20-30 ft wide

Flower Color

Rose-purple

Foliage Color

Dark green

Landscape Use

Shade Tree, Specimen / Accent

Garden Style

Pollinator / Wildlife

Soil

Alkaline Tolerant, Sandy / Rocky, Well-Drained

Companion Plants

Deer grass, Desert marigold, Parry's penstemon, Red yucca

Toxic — Pets & Livestock

Bark, seeds, and foliage toxic to people, dogs, and livestock; highly toxic to horses.

Care Instructions

Light: Full sun; in Phoenix, avoid intensely reflected heat from west-facing walls and pavement.

Water: Moderate water in Phoenix. Water deeply and regularly during establishment; once established, allow the upper soil to dry between deep irrigations. Provide supplemental water during prolonged summer heat.

Soil: Well-drained sandy, loamy, or gravelly soil. Tolerates alkaline soil and relatively poor fertility; avoid persistent wetness and compacted, poorly drained sites.

Mature size: Typically 30–40 feet tall and 20–30 feet wide; occasionally larger.

Bloom: Showy clusters in spring, generally April–May; timing and abundance vary with local conditions.

Evergreen / deciduous: Deciduous.

Growth rate: Fast with adequate water and good drainage.