Scientific: Vachellia pennatula var. pennatula (formerly Acacia pennatula)
Common: feather vachellia, feather acacia, fern-leaf acacia, Sierra Madre acacia
Family: Fabaceae (Leguminosae)
Origin: Native to relatively dry and well drained sites between 1,500 to 8,500 feet in elevation throughout all but northern Mexico, south into El Salvador, Guatemala, Honduras and Nicaragua, and northern South America in southern Columbia (Valle) and Ecuador.

Pronounciation: Va-KEL-lee-a pen-na-TO-la

Hardiness zones
Sunset
8, 9, 12-24
USDA 8-10

Landscape Use: Fine accent small tree, background, xeric and native landscapes only.

Form & Character: Semi-evergreen tree, lacy and fern like, delicate except for when viewed up close, then watch out for those thorns!

Growth Habit: Variably slow to moderate to 15 to 30 feet with variably equal or greater spread.

Foliage/texture: Fern or feather like, lacy, pinnately compound foliage, leaves to 6 to 8 inches long, leaflets to 1 inch nearly linear, gray-green, surprisingly pubescent, prominent auxiliary buds pubescent, young stems have prominent lenticels, axillary spines to 1 inch that hidden under the foliage, spines can be highly irritating. Stems are gray brown to beige with the resultat bark becoming slightly spongy and fissured with age; fine texture.

Flowers & fruits: Panicles of small orange powder puff flowers on mostly old wood emerging during a brief deciduous period in spring, flowers fragrant. Fruit is a 3 to 5 inch dark brown pod that ripens in late summer.

Seasonal color: Orange flowers in spring.

Temperature: Hardy to 22oF when mature, but frost sensitive when young.

Light: Full sun, NO shade.

Soil: Tolerant of all lower desert soils, but performs best under well-drained soil conditions.

Watering: Feather vachellia requires little to no supplemental irrigation once established. However, it will grow much faster and larger if irrigated.

Pruning: Feather acacia has a tendency to send basal sucker and develop water sprouts at point of previous pruning cut, else prune to shape.

A special note to those with ears to hear: Because of it's stipular spines, wear leather gloves and a long sleeve shirt when pruning feather vachellia or else you will undoubtedly bleed, itch and fester!

Propagation: Seed, must acid scarify, 95% sulfuric acid for 30 minutes or until dark seed coat initially lightens. High plant to plant variability makes seed selection based on parental traits important. Harvest seeds for propagation as soon as they "rattle" in the pod.

Disease and pests: Texas root rot

Additional comments: Feather vachellia is a rather rare medium small landscape tree in Phoenix. Except for the prominent stipular spines which are hard to work with, this is a beautiful small tree for drier sites with a relatively low maintenance requirement once established. In Phoenix, it has a spring deciduous habit at time of flowering. Several mature specimens are located in downtown Phoenix near the state capital building.

The genus name change of this graceful landscape taxon from Acacia to Vachellia occurred in 2005.