Description
Form: Shrub.
Leaf retention: Winter evergreen but drought- and frost-deciduous.
Growth rate: Rapid.
Mature Size: 3-5' (1-1.5m) high and wide.
Flowers: Yellow rays, with orange to brown centers, on tall stalks above leaves.
Bloom: Mid-fall, through winter, to mid-spring.
Fruit: Tufted seed which is dispersed by the wind.
Leaves: Triangular to oval, silvery blue-green, fine hairs.
Stems: No thorns, brittle and easily broken. An aromatic resin seeps from the ends
of broken stems.
Roots: Wide and shallow, along with a deep taproot. This plant is very difficult to
transplant.
Wildlife: Attracts bees and butterflies, especially when nothing else around is
blooming.
It is browsed by deer and bighorn sheep, but is not a useful forage for cattle.
Toxic / Danger: Not to animals or humans. This plant is allelopathic and its leaves
produce a water-soluble substance that inhibits the growth of some winter annual plants.
It competes strongly with buffalo grass.
Origin: California, Nevada, Arizona, Utah, Mexico.
Cultivation and Uses
USDA hardiness zones: 7-10 in arid regions. May die to the ground during a freeze and
grow back from its roots in the spring.
Heat tolerant: Yes.
Drought tolerant: Yes.
Sun: Full sun.
Water once established: Monthly. Overwatering causes excessive growth.
Soil: Very well drained, dry, low organic content, pH 6.6-8.5 (neutral to alkaline).
Prune: After flowering, trim tall flower stalks down to leaf level. Deadheading spent
flowers reduces reseeding. The plant can be cut to near ground level in mid-spring to avoid
a shaggy summer appearance. It is easily eradicated by pulling it up with its taproot.
Litter: Low except for pruning.
Propagation: Seed. This plant reseeds freely and can form a thicket dependent upon
the amount of rainfall received.
Uses: Ornamental, xeric garden, erosion control on level ground and modest slopes.
Its aromatic resin is burned as incense, and the aroma has been compared to that of
frankincense. It has also been used as chewing gum, a glue, and to waterproof containers.
Comments
This plant is a member of the Aster family (Asteraceae).
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