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ROBINIA 'Purple Robe'

Image of Robinia 'Purple Robe'

Michael Charters, www.calflora.net

Family

Fabaceae

Botanical Name

ROBINIA 'Purple Robe'

Plant Common Name

Hybrid Black Locust, Purple Robe Locust

General Description

A tough tree with billowy foliage and pretty violet-pink late spring flowers, 'Purple Robe' is no less than easy-to-grow. A small to medium-sized deciduous tree, it is a hybrid. Some consider it a cross between cultivars of Robinia ambigua and Robinia hispida while others believe it a cross between Robinia pseudoacacia and Robinia hispida.

It has compound leaves (made up of many smaller oval leaflets) that emerge bronze-red in spring, maturing to blue-green. Its fragrant, rosy-purple, wisteria-like blossoms open in mid- to late spring, attracting honeybees. Over the summer purplish brown seedpods form and ripen and can persist on the irregular, picturesque branches in winter after the yellow-green autumn leaves fall. The pods do split open to drop seeds that will germinate.

Purple Robe locust requires full sun or nearly so and excels in moist loamy soil. It is tolerant of drought as well as any infertile ground and mild saltspray. 'Purple Robe' is an excellent specimen plant and shade tree with pretty flowers, especially nice to add in sites with less-than-optimal growing conditions. Root suckers should be removed to keep this plant from creating a thicket; young saplings should be promptly removed for the same reason. Borers can wreak havoc upon trees that are stressed from root constriction or excessive drought.

The honey made from the flowers of locust has a distinctive color and flavor that can be well-received and desired.

Characteristics

  • AHS Heat Zone

    9 - 3

  • USDA Hardiness Zone

    5 - 8

  • Sunset Zone

    2a, 2b, 3a, 3b, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24

  • Plant Type

    Tree

  • Sun Exposure

    Full Sun

  • Height

    30'-40' / 9.1m - 12.2m

  • Width

    20'-30' / 6.1m - 9.1m

  • Bloom Time

    Spring, Late Spring

  • Native To

    Hybrid Origin

Growing Conditions

  • Soil pH

    Acidic, Neutral, Alkaline

  • Soil Drainage

    Average

  • Soil type

    Clay, Loam, Sand

  • Tolerances

    Pollution, Drought, Salt, Soil Compaction

  • Growth Rate

    Fast

  • Water Requirements

    Drought Tolerant, Average Water

  • Habit

    Upright/Erect

  • Seasonal Interest

    Spring, Summer, Fall, Winter

Ornamental Features

  • Flower Interest

    Showy

  • Flower Color

    Rose, Violet

  • Fruit Color

    Purple, Brown

  • Foliage Color (Spring)

    Red, Crimson, Bronze

  • Foliage Color (Summer)

    Green, Blue Green

  • Foliage Color (Fall)

    Yellow Green

  • Bark Color

    White, Brown, Gray

  • Fragrant Flowers

    Yes

  • Fragrant Fruit

    No

  • Fragrant Foliage

    No

  • Bark or Stem Fragrant

    No

  • Flower Petal Number

    Single

  • Repeat Bloomer

    No

  • Showy Fruit

    No

  • Edible Fruit

    No

  • Showy Foliage

    Yes

  • Foliage Texture

    Medium

  • Foliage Sheen

    Matte

  • Evergreen

    No

  • Showy Bark

    Yes

Special Characteristics

  • Bark Texture

    Corky

  • Usage

    Feature Plant, Shade Trees, Street Trees

  • Sharp or Has Thorns

    Yes

  • Invasive

    Sometimes

  • Attracts

    Birds, Butterflies

  • Self-Sowing

    Yes