Scientific: Buddleja marrubiifolia (syn. Buddleia marrubifolia) - is it Buddleja or Buddleia?
Common: wooly butterfly bush
Family: Loganiaceae
Origin: Southwest Texas into Chihuahua between 1,500 and 3,000 feet elevation.

Pronounciation: Bud-LEE-ja mar-ru-bye-ee-FOO-lee-a

Hardiness zones
12, 13
USDA 8-11

Landscape Use: An accent or background plant. This is a gray accent shrub that contrasts well against other shrubs with deep green foliage. All Buddleja species can be used as garden plants to attract butterflies.

Form & Character: Rounded and spreading, unruly, informal to flat out rank if heavily irrigated, free spirited.

Growth Habit: Herbaceous to semi-woody perennial, evergreen, moderately fast, ranging and arching to 5 feet with equal to greater spread.

Foliage/Texture: Leaves small to 1 inch, opposite, densely tomentose, grayish white, elliptical-shaped with crenate margins; medium fine texture.

Flowers & Fruits: Terminal and axillary clusters of orange tubular flowers, fruit inconspicuous.

Seasonal Color: Flowers in spring and early summer.

Temperature: Tolerant to 15oF, heat loving.

Light: Mandatory full sun, and absolutely no shade.

Soil: Tolerant

Watering: Infrequent, especially during summer, no winter irrigation.

Pruning: Occasionally lightly head back to rejuvenate growth rate, prune in fall.

Propagation: Cutting

Disease and pests: None

Additional comments: Wooly butterfly bush is an uncommon shrub, yet is a great shrub for Phoenix landscapes with a xeric or desert theme. Hummingbirds and butterflies will love it! People who like formal landscapes will be frustrated by this plant because of its informal habit of growth and its inability to conform to a prescribed geometrical shape. This means that for you landscape neat freaks, it has an informal habit and CANNOT be trained into a landscape bowling ball. But those with informal tastes will enjoy its free-spirited presence in the landscape.

Buddleja (or probably more correctly spelled Buddleia) is a large genus of over 140 species worldwide, some of which are highly invasive in temperature ecosystems. B. davidii is a nationally popular yet regionally invasive deciduous landscape shrub that does not perform well in Phoenix. This is not true of B. marrubiifolia, a shrub that should be on everyone's 'cool plant list' in Phoenix.