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Leucophyllum spp.
silverleaves
Southwestern United States and northern Mexico
Overview
Leucophyllum spp. is a genus of about 12 species of evergreen shrubs in the family Scrophulariaceae, native to the Chihuahuan Desert and adjacent scrub of the southwestern United States and northern Mexico. Plants form dense, rounded, twiggy shrubs 2-8 ft (0.6-2.4 m) tall and wide, clothed in small, alternate, often silvery-grey leaves 0.3-1 in (8-25 mm) long that are covered in dense felted hairs. The bell-shaped, five-lobed flowers measure 0.5-1 in (13-25 mm) across and open in shades of violet, magenta, pink, lavender, and white, set singly in the leaf axils. Flowering is triggered by rising humidity and soil moisture after summer and autumn rains, giving rise to common names such as barometer bush and Texas ranger. The grey foliage colour comes from a coat of branched hairs that reflect sunlight and reduce water loss. The genus is adapted to hot, dry, alkaline desert soils and tolerates extreme heat and drought once established, but rots in heavy, wet, or poorly drained ground. Cold hardiness varies by species, with most tolerating brief frost to about 10 F (-12 C). L. frutescens is the species grown most often as an ornamental hedge and screen.
Native Range
The genus is native to the Chihuahuan Desert and surrounding scrub of western Texas, New Mexico, and northern Mexico. L. frutescens ranges through the Rio Grande Plains and into the Mexican states of Coahuila, Nuevo Leon, and Tamaulipas.Suggested Uses
Leucophyllum spp. is used as an informal hedge, screen, foundation shrub, and specimen in hot, dry, low-water gardens. Plants are spaced 3-5 ft (0.9-1.5 m) apart for a continuous hedge. The silver foliage contrasts with green-leaved desert plantings.How to Identify
Appearance
Size & Dimensions
Height2' - 8'
Width/Spread2' - 8'
Bloom Information
Leucophyllum spp. flowers irregularly through the warm months, with heavy flushes appearing a few days after summer and autumn rains rather than on a fixed schedule. Each flush lasts several days to a week before fading. In cultivation the cycle repeats whenever humidity and soil moisture rise.
Detailed Descriptions
Flower Description
violet, magenta, pink, lavender, or whiteFoliage Description
silver-grey to grey-greenGrowing Conditions
Sun Requirements
Requires 6-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Grow Leucophyllum spp. in full sun in poor to moderately fertile, sharply drained alkaline soil with a pH of 7.0-8.5. The genus needs heat and free drainage and is well suited to gravel, rock, and xeriscape gardens. Water sparingly once established, as overwatering and humid, poorly drained sites cause root rot and cotton root rot. Rich soils and heavy feeding produce soft, sparse growth. Most species tolerate brief frost but are set back by prolonged cold, wet winters. Light shearing keeps plants dense, while hard pruning into bare wood regrows slowly.Pruning
Light shearing or tip pruning in late winter or after a flowering flush keeps Leucophyllum spp. compact. The genus regrows slowly from old leafless wood, so hard renovation cuts often leave bare patches. Formal shearing reduces flowering, since blooms form on soft new growth.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
early spring
Container Growing
✓ Suitable for container growing
Minimum container size: 5 gallons