Scientific: Ambrosia dumosa
Common: white bursage, burroweed, burrobush, white burrobush, desert ragweed
Family: Asteraceae
Origin: Mojave desert of California, Nevada, and Utah and the Sonoran Desert of Arizona and northwestern Mexico occurring from sea level to 5,500 feet in elvation.
Pronounciation: Am-BRO-see-a du-MO-sa
Hardiness zones
Sunset 11-13
USDA 9-10 (arid zones only)
Landscape Use: Xeriscape, desert native plantings, desert restoration projects, low growing and spreading filler plant, mass plantings, highway medium plantings.
Form & Character: Rounded, mounding, grey, dense, regular, dull and uninspiring, dry.
Growth Habit: Evergreen, mostly herbaceous perennial subshrub, winter active, highly branched and dense to 2-feet tall with slightly greater spread. It is generally quiescent during summer and can become leafless during long periods without water, irrigation will increase vigor and size.
Foliage/Texture: Leaves are alternately arranged, ovate, pinntified, mostly evergreen, highly glaucous, very small, young stems densely pubescent (haired); fine texture.
Flowers & Fruits: Small yellow flowers with staminate and pistallate heads on a single plant. Fruits bur-like and ranging in color from golden to purple to brown.
Seasonal Color: White bursage can become more heavily vegetated in winter if winter rains materialize; otherwise, none.
Temperature: Tolerant to 22oF.
Light: Full sun
Soil: Well-drained soils are required. Slopes, with rocky dry soils are best.
Watering: None needed after establishment. Occasional water during the winter may be applied if winter rains fail to materialize in order to invigorate. Responds well to supplemental water especially during the summer; however, too much extra water will encourage rank growth.
Pruning: Slight shearing during the fall before the onset of winter growth is used to increase landscape symmetry.
Propagation: Seed; seeds require a one-month cold stratification treatment to germinate.
Disease and Pests: Root rot in poorly drained soils is common.
Additional comments: White bursage is a homely-looking subshrub without any significant aesthetic character. It is best (and only) used as a companion filler plant for native plantings or desert restoration projects.
Severe Allergy Alert: Ambrosia dumosa is a severe allergen. Because of this it is not a plant that I recommend for use in Phoenix landscape gardens.
