ID Characteristics
This plant is in the Fabaceae - the legume (pea and bean) family.
Fairy duster has a naturally compact, rounded form - 2 x 2 feet in the wild, larger under cultivation. It is dense, even at ground level. Birds and small animals may shelter under its branches. Though the leaves may drop with winter's cold, the branches to not die back in a typical Tucson winter (temperature stays above 15°F).
The alternate leaves of fairy duster each have 4 or 6 sections, arranged opposite each other, each section having about 16 tiny leaflets. This type of leaf is called doubly pinnate or bipinnate. The whole leaf is only about 1.5 inches long and an inch wide. The leaflets fold toward each other in the evening (see second photo above) and may not reopen if the morning is cool and cloudy. (In the upper photo, the small, red balls are flower buds.)
The puff ball "flower" is composed of 4-6 flowers and is about 2 inches wide. The showy part is the long, threadlike stamens. Color ranges from almost white to dark pink and may darken as the flower ages.
The seed pods are flat, about 2 inches long. When mature, they open to eject seeds, each half curling backward. The pods can stay on the plant for many months. They are often hidden under the foliage and so do not detract from the plant's appearance. It is not unusual to see flowers, new seed pods, and old, curled seed pods, all on the same plant.