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Senegalia spp.

hook-thorns

Fabaceae

Tropical and subtropical Africa, Asia, and the Americas

Attracts Pollinators Drought Tolerant

Native to North America

SunFull Sun

WaterLow · drought-tolerant

HardinessZones 8–11

Overview

Senegalia spp. is a genus of about 200 species of trees, shrubs, and woody climbers in the legume family (Fabaceae), formerly included in a broadly defined Acacia spp.. Plants range from low shrubs to trees 50 feet (15 m) tall and are armed with scattered, often hooked prickles along the stems rather than the paired straight spines of related genera. The leaves are bipinnate, divided into many small leaflets that give a feathery outline. Flowers are tiny and crowded into rounded heads or cylindrical spikes 0.4-2.5 inches (1-6 cm) long, in cream, white, pale yellow, or occasionally pink, and are followed by flat or twisted legume pods. Senegalia spp. is widespread across the tropics and subtropics of Africa, Asia, and the Americas, in savanna, dry woodland, thornscrub, and forest margins, often on poor soils. Several species are used commercially, including S. senegal, the source of gum arabic, and S. catechu, used for catechu dye and tannin. Most species are frost-tender, and the recurved prickles catch on skin and clothing, the main drawback near paths.

Native Range

Native across the tropics and subtropics of Africa, Asia, and the Americas, with many species in Africa and a number in the drier parts of the Americas, including the southwestern United States. Plants grow in savanna, dry woodland, thornscrub, and forest edges, usually in full sun on well-drained soils.

Suggested Uses

Used as drought-tolerant shade, screen, and barrier plantings in warm, dry climates, and for soil stabilization and nitrogen enrichment on poor ground. The thorny species form stock-proof hedges, while S. senegal is grown in plantations for gum arabic. Smaller species suit native and wildlife gardens, where the flowers feed pollinators.

How to Identify

Identify Senegalia spp. by its feathery bipinnate leaves and by the small, scattered, often hooked prickles set along the stems and branches, rather than paired straight spines at the nodes. The tiny flowers cluster into fluffy rounded heads or cylindrical spikes in cream to pale yellow. The hooked prickles and spike or globe flower clusters separate it from Vachellia spp., the thorn acacias, which bear paired stipular spines.

Appearance

Size & Dimensions

Height3' - 50'

Width/Spread6' - 30'

Colors

Flower Colors

Foliage Colors

Bloom Information

Bloom Period

~6 weeks

Spring Summer

Flowering is usually in spring and summer, often triggered by rains in seasonally dry climates, so timing varies with locality. The fluffy cream to yellow flower clusters appear over several weeks and are visited by bees and other insects. Flat or coiled seed pods follow and ripen later in the season.

Detailed Descriptions

Flower Description

cream, white, or pale yellow

Foliage Description

green, feathery

Growing Conditions

Sun Requirements

SunFull Sun

Requires 6-12 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 8.0(Neutral)

357912

Soil Types

sand loam rocky

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

tender

Time to Maturity

3-8 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Senegalia spp. are grown in full sun in well-drained soil and tolerate heat, drought, and poor, sandy or rocky ground once established, fixing nitrogen through root nodules. Young plants are watered until established, after which most need little irrigation. Hardiness varies widely: many tropical species are frost-tender, while some, such as S. greggii, withstand light frost in roughly USDA zones 8-9. Growth is moderate to fast, and plants resprout after damage. Propagation is from scarified seed, which germinates readily. The thorny stems and, in some species, a suckering or seeding habit can make plants hard to manage.

Pruning

Pruning is done in the dry or dormant season to shape young plants, raise the canopy, or remove dead, crossing, or low thorny branches. Shrubby species can be cut back to renew growth. Cuts are kept clean, and the thorny prunings are bulky to handle.