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Common Name:

Black Locust

Scientific Name:

Robinia pseudoacacia

Family Name:

Fabaceae (Leguminosae)


Black Locust is a medium to large deciduous tree with an irregular upright oval crown of bluish green leaves. Tree sucker to form colonies and are used for reclamation work. Locust borers and locust leaf miners limit usefulness in much of our region.

Plant Habit or Use:

Tree, medium tree, large tree


sun, partial sun

Flower Color:

White, pea-like pendent racemes, fragrant, attractive

Blooming Period:


Fruit Characteristics:

Flat pe-pod like legumes, brown, ripen in fall.


40 ft to 50 ft (100 ft)


20 ft to 40 ft

Earth–Kind® Index:

  • Heat Tolerance: High Heat Tolerance
  • Water Requirements: Low Water Use
  • Soil Requirements: Low Soil Requirements
  • Pest Tolerance: Medium Pest Resistance
  • Fertility Requirements: Low Fertility Requirements
Explanation of the Earth–Kind® Index breakdown

Firewise Index

Explanation of the Firewise Index numerical value

USDA Hardiness Zones:

4, 5, 6, 7, 8, 9

Regions that intersect these hardiness zones:
Region A - Panhandle and High Plains Region B - North and Central Texas Region C - Northeast and East Texas Region D - West Texas Region E - Upper Rio Grande Region F - Hill Country and Central Coast Region G - Southeast Texas Region H - Rio Grande Valley
Click image for enlarged map of USDA Hardiness Zones

Additional Comments:

Fixes nitrogen via symbiotic bacteria in roots. A favorite species for fence post production. Tends to naturalize readily outside its native range and can become a weed under certain conditions. Used heavily in strip mine reclamation and erosion control. Can develop chlorosis on high pH soils.
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A Special Note about Cool Season Annuals

Cool season annuals typically are planted in the fall or early winter and flower in early spring under moderate temperatures. This group of plant materials includes: pansies, snapdragons, violas, dianthus, flowering cabbage/kale, etc. Because cool season annuals flower in the spring when conditions are mild, most have limited heat tolerance.

As a result cool season annuals do not receive a high Earth–Kind® index despite their outstanding landscape qualities.