Quercus hypoleucoides aka Silverleaf Oak

Quercus hypoleucoides is known as silverleaf oak or whiteleaf oak. It belongs to the beech family, Fagaceae. Its native range runs from Arizona to western Texas and northern Mexico. It grows in mountain woods, moist canyons, and along ridges. It occurs in pine-oak and conifer forests at high elevations. These habitats lie about 4,900–8,900 feet [1,500–2,700 metres] above sea level.

This oak can form a shrub or a small tree. Its leaves stay year-round, though some plants are semi-evergreen. Trees often reach 20–33 feet [6–10 metres] in height. Some reach about 65 feet [20 metres]. Shrub forms stand about 6.5–10 feet [2–3 metres] tall. One garden account gives a spread of 13 feet [4 metres]. The crown is rounded and spreads outward. Growth is slow, and more moisture can help it become tree-sized.

The leaves give this oak much of its garden value. They are narrow, leathery, and arranged alternately along the twigs. Each leaf measures about two to four inches long. The upper surface shines yellow-green, while pale hairs cover the underside. Leaf edges curl under and may bear a few teeth. The tips end in a narrow point. Thin, dark gray bark has shallow cracks and narrow ridges. Twigs often carry white fuzz, with clustered reddish-brown buds at their tips.

Male and female flowers grow on the same plant. Yellow-green male flowers hang in long catkins. Tiny female flower spikes sit where leaves meet the stem. The flowers appear with new leaves, and wind carries their pollen. Oblong acorns turn light chestnut brown as they mature. A scaly, bowl-like cup covers about one-third of each nut. The acorns mature in early fall, after one or sometimes two seasons. The tree attracts wildlife and serves as an ornamental for its pale-backed leaves.

Grow this oak in sun and soil that drains well. It accepts sand, loam, or clay, and mildly acid to mildly alkaline soil. It prefers moist soil but also withstands drought. Sources place it in USDA zones 7–10. Dormant trees can withstand about 5°F [-15°C]. Hot summers suit it better than cool maritime summers. Poor wood ripening in cool summers can lead to winter frost damage. PFAF rates its food value low but lacks species-specific seed-use details. It warns that tannins can cause illness when eaten in excess. PFAF reports a 2013 IUCN assessment of Least Concern.