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Acacia angustissima var. Hirta

Fern acacia or White-ball acacia

In the warm season, these low feathery shrubs give a soft tropical feeling; and are a larval foodplant for the Mexican Sulphur butterfly.

A thornless, feathery deciduous shrub or small tree. The size varies considerably from under three feet, to five or more feet tall in cultivation. Dark green leaves are divided into numerous tiny leaflets, giving the plant a soft, feathery appearance. Flowers are white, tinged with pink or lavender, and arranged in compact heads about ?” in diameter. The fruit is an oblong brown pod containing seeds. The seeds are mottled gray, brown, dark brown or black. The pods break and scatter seed in late summer or fall. Seed-grown plants will show variability in size and other characteristics.


QuickFacts Description Growth Forms: Shrub, Groundcover. Mature Height: 4-5 feet Mature Width: 4-5 feet Predominant Flower Color: Cream Flowering Seasons: Fore-Summer (May - June), Summer Rainy Season (July - mid September) Gardening Planting Zone: Transition zone, Arid or natural zone Water Use: Low Exposure: Partial Shade to Full Sun Hardy to: Hardy, but threshold unknown Planting Season: Spring (mid February - April), Fall (October - November) Growth Rate: Moderate Availability: Not common; check nurseries specializing in native plants. In the Wild Habitat: Hillsides and canyon slopes; desert grasslands; oak woodland. Elevation: 3000 to 6500 ft. Native Range: Missouri to Texas and Arizona, southward to Guatemala; southern Florida

Landscape Use: Butterfly Garden, Massing, Native Plant Garden, Natural Area, Wildlife Garden.

In nature, fern acacia varies greatly in height. Landscape plants in the Tucson area tend to stay at or below 3? tall. The plant is desirable for its soft ferny appearance rather than for its pale white flowers. It really does look like a fern! Fern acacia is a grassland plant and combines well with soft bunchgrasses in a butterfly or bird garden. It?s thornless and appropriate near patios and pools. It also works nicely in masses, as the delicate ferny foliage stays fresh and green all summer. Since plants have bare stems in the winter, it?s a good idea to locate fern acacia in sunny corners or edges of the garden.

Planting Tips: Plant from one- or five-gallon containers in fall or spring. Fern acacia may be planted in native soil, although establishment is quicker if soil is well-drained; the presence of sand and rocks helps. Because fern acacia spreads by rhizomes (underground stems), soil needs to be loosened 2-3 feet on each side of the plant. Water thoroughly, immediately after planting.

Gardening Tips: To look its best, fern acacia needs to be deeply watered about every two to four weeks in summer. Young plants need to be watered each week for the first year. Leaves fall during the cold days of winter. Wait for stems to green up in spring before carefully pruning away any dead stems. Old, ratty plants may be cut back hard in spring to rejuvenate and thicken, but this may not be necessary every year.

Problems: Plants drop their leaves in winter, leaving bare stems.

Attracting Wildlife

Wildlife Attraction: Butterflies, Larval food plant.
Wildlife Use: Larval foodplant for Mexican Sulphur. Also nectar for many kinds of insects.

Names

Family: Fabaceae (Legume Family)
Scientific Name (Genus species): Acacia angustissima var. Hirta
Prounounced ah-KAY-shah an-gus-TISS-uh-mah “Angustissima” means narrow leaves. The common name, Fern acacia, refers to its feathery, fernlike appearance.
Common Names: Fern acacia, White-ball acacia
Spanish Names: Cantemo, Palo de puque, Barbas de chivo, Guajillo
Variety: hirta (Nutt.) Rob.

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