Botanical Name: Robinia pseudoacacia
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Common Name: Black Locust  
Plant photo of: Robinia pseudoacacia
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Water Saving Tip:

Even though it's hot, your lawn only needs to be watered twice a week to stay healthy.

And don't water the whole lawn for a brown spot—drag out a hose.

  • Anatomy

  • Culture

  • Design

Plant Type

Tree

 

Height Range

40-60', 60-100'

 

Flower Color

White

 

Flower Season

Spring

 

Leaf Color

Blue Green

 

Bark Color

Grey

 

Fruit Color

Brown

 

Fruit Season

Fall, Persistent

Sun

Full

 

Water

Low, Medium

 

Growth Rate

Fast

 

Soil Type

Sandy, Clay, Loam, Rocky, Unparticular

 

Soil Condition

Average, Rich, Poor, Well-drained, Dry

 

Soil pH

Neutral, Basic

 

Adverse Factors

Invasive, Thorns/Spines

Design Styles

Ranch, Spanish

 

Accenting Features

Fragrance, Showy Flowers

 

Seasonal Interest

Spring

 

Location Uses

Background, Park

 

Special Uses

Naturalizing

 

Attracts Wildlife

n/a

Information by: Stephanie Duer
Photographer: Connon Nursery
  • Description

  • Notes

Black locust is a very fast-growing, deciduous tree, typically 40 to 50 feet tall (though sometimes reaching 70 feet) and nearly as wide. It has pinnately compounded leaves that are a dark, dull blue-green, with leaves dropping in the fall before much color change. Flowers are pendulous, white, and fragrant, and bloom late May to early June. Flowers are followed by flat pods that ripen in fall and persist into winter. Bark is dark grey with deep ridges. Wicked thorns, hard wood, and suckering habit makes the Black Locust a challenging maintenance project and best suited for large, naturalized areas.
The flowers on this tree are lovely and very fragrant; its just unfortunate they are on this tree. It can spread both from root suckers and seeds, and can become very invasive. It might be best suited to large, natural areas where its thorns and expansiveness are not a detriment. There is a lovely stand at the Kol Ami Cemetary on 11th Ave, and they are asserting themselves 1000 feet away in the Greater Aves Conservation Garden. If you choose to plant it, it grows best in full sun in well drained soil, though it will tolerate part sun situations. Tolerates high temperatures, poor soils, nitrogen-poor soils, and high pH. It does have a history of breakage in wet storm events in SLC.