Quercus emoryi aka Emory Oak

Quercus emoryi, or Emory oak, belongs to the beech family. Other names include black oak and blackjack oak. It grows wild in Arizona, New Mexico, Texas, and northern Mexico. Its habitats include canyons, dry foothills, and mountain slopes. Trees grow best in sheltered valleys within this range. This slow-growing oak can also take a shrub form. It keeps its leaves but may shed them during drought.

One growing guide gives a height of 39 feet [12 metres]. Other accounts describe trees reaching 60–65 feet [18–20 metres] or more. A short trunk supports stout limbs and a rounded crown. The dark gray bark thickens and forms furrows and scaly ridges. Young twigs are yellow-brown and hairy, with pointed, hairy buds. The stiff, glossy leaves have a narrow, pointed shape. Their edges may be smooth or bear sharp teeth. Leaf veins sit below the upper surface and rise beneath.

Male and female flowers grow on the same tree. Wind carries pollen between the flowers. Male flowers hang in long, yellow-green catkins. Tiny female flowers form near the leaf bases. Flowers appear with new leaves; one source gives May. The oblong acorns mature that year, in early fall. A thick, scaly cup holds part of each nut. Seed crops vary, with heavy years followed by lean ones.

Grow Emory oak in sun, with periodic watering in summer. Young trees can cope with some shade from the side. It accepts several soils, but favors deep, fertile loam. It also grows in clay and prefers moist soil. It tolerates mildly acid through mildly alkaline soil. Sources differ on cold limits: one lists USDA zones 6–9. Another places its hardiness limit at zone 8. Cool British summers can leave wood unripe and prone to frost damage. Its deep taproot makes older nursery plants hard to move.

Emory oak can form the canopy of a woodland garden. Its sweet seeds have long served as food in its native range. People eat them raw or cooked, or grind them into flour. Bitter seeds need washing to remove tannins before use. One source reports no known hazards, but this is not a safety guarantee. Insects can cause galls, which provide tannin and dye. The hard, heavy wood serves as fuel. Fresh leaves used as mulch can hinder other plants' growth.