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Quercus hypoleucoides
silverleaf oak
Southwestern US and northern Mexico (sky island mountains of Arizona, New Mexico, Texas; pine-oak woodlands, 5,000-8,000 feet / 1,500-2,400 m)
Overview
Quercus hypoleucoides is the silverleaf oak, an evergreen tree growing 240-480 inches (600-1,200 cm / 20-40 feet) tall and 180-300 inches (450-750 cm / 15-25 feet) wide. Lanceolate leaves 2-4 inches (5-10 cm) with glossy dark green upper surfaces and bright silvery-white dense felt (tomentum) on the undersides — the bicolored leaves flash white when wind turns them. The species name 'hypoleucoides' means 'resembling white beneath' (Greek hypo spp. + leukos spp. + oides spp.). The white leaf undersides are the whitest of any North American oak. The leaf margins roll inward (revolute) — an adaptation to the arid climate. In the beech family (Fagaceae spp.), section Quercus spp. (red oaks). Acorns 0.5-0.8 inch (12-20 mm) in shallow cups, maturing in 1 year — consumed by Merriam's turkey, black bear, and band-tailed pigeon. Native to the sky island mountains of the American Southwest (Arizona, New Mexico, Texas) and northern Mexico, growing in pine-oak woodlands at 5,000-8,000 feet (1,500-2,400 m). The Madrean sky islands are isolated mountain ranges surrounded by desert — the disjunct populations create genetic isolation. Drought-tolerant once established. Intolerant of humid summer climates east of the Great Plains. Non-toxic (acorns edible after leaching). Deer-resistant. Full sun. Native. Zones 7-10. Growth rate is slow to moderate.
Native Range
Native to the sky island mountains of the American Southwest (Arizona, New Mexico, Texas) and northern Mexico, growing in pine-oak woodlands at 5,000-8,000 feet (1,500-2,400 m).Suggested Uses
Commonly planted as a specimen and shade tree in arid southwestern landscapes in zones 7-10. The bicolored leaves (dark green above, silvery-white beneath) flash white in wind. Sky island native. Drought-tolerant. Intolerant of humid eastern climates. Non-toxic. Native.How to Identify
Appearance
Size & Dimensions
Height20' - 40'
Width/Spread15' - 25'
Reaches mature size in approximately 35 years
Bloom Information
Spring (April-May) — inconspicuous catkins. Acorns 0.5-0.8 inch (12-20 mm) in shallow cups, maturing in 1 year. Wildlife food (turkey, bear, pigeon). The bicolored evergreen foliage is the year-round feature.
Detailed Descriptions
Foliage Description
Glossy dark green above; bright white to silvery-white dense felt (tomentum) beneath; lanceolate, 2-4 inches (5-10 cm); margins roll inward (revolute)Growing Conditions
Sun Requirements
Requires 6-12 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
Full sun. Well-drained soil. Drought-tolerant once established. Adapted to the arid Madrean sky-island climate — intolerant of humid summer climates east of the Great Plains. The bicolored leaves flash white in wind. Non-toxic. Deer-resistant. Native. Zones 7-10.Pruning
Prune in winter (January-February) when dormant. Remove dead, damaged, and crossing branches. The natural crown shape develops over decades. Do not top.Pruning Schedule
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winter