Photo: Homoarborea, CC0 · Wikimedia Commons

Bluejack Oak

Quercus incana

Also called sandjack oak, upland willow oak, cinnamon oak, Quercus cinerea.

A small red oak of southern sandhills with narrow blue-green leaves, gray-felted beneath, that often hang on into winter.

Drought tolerantWildlife valueFall color

Type: Small tree
Mature height: 20–40 ft
USDA zones: 6–9
Growth rate: Slow
Sun: Full, Part
Soil moisture: Dry
Grows wild in: Sandy barrens and dry uplands
Native range: 11 states, north to Virginia, south to Florida and west to Texas
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Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina, Texas and Virginia
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Bluejack oak is a red oak of the open longleaf pine woods of the Coastal Plain, often beside turkey oak. The name comes from the blue-green of its leaves and its kinship with blackjack oak. Fire top-kills it, and it sprouts back from the root crown with more stems than before. It is recommended for longleaf pine stands for the wildlife it feeds. Use it as a small shade tree on dry sand, or as a thicket for birds at the edge of a pine planting.

Size, growth and what to expect

Bluejack oak is a slow grower, so our growth estimator gives it about a foot a year. It is a small tree, usually to 35 feet and at most about 50. Expect 20 to 40 feet, with a crown 25 to 45 feet wide.

It flowers from March to May. The acorns take two seasons to ripen and are ready in September and October of the second year. They are small, three eighths to five eighths of an inch long. Fox squirrels, deer, wild turkeys and quail eat them. In a study of 12 oaks, fox squirrels highly preferred them.

It grows wild on the Atlantic and Gulf Coastal Plain from southeast Virginia to central Florida, west to central Texas and north to southeast Oklahoma. It keeps to deep sand on ridges, barrens and dunes.

How to grow Bluejack Oak

Bluejack oak wants full sun or light shade and a deep sand or sandy loam that drains fast, acid rather than limy. It is at home where the ground stays dry for weeks, and it will not take wet soil or salt spray. Set trees 25 feet apart, and keep each one 20 feet from a wall and 15 feet or more from overhead wires.

Saplings ship potted. It does not handle root disturbance well, so plant it young and leave it where it goes. Plant it dormant, from leaf fall until bud swell, in a hole wider than the pot and no deeper. Set the root flare at the soil line, put the sand back in, and keep the mulch clear of the trunk. Red oak acorns need a winter before they sprout. Sow them in fall three quarters of an inch deep under hardware cloth. For spring, hold them damp in the refrigerator for four to twelve weeks first.

Water every week or two through the first summer, then only in a long drought. Deer seldom browse it except where they are many and the sprouts are tender. A tube or cage for the first two years still guards the young stem. Keep the mulch thin at the trunk so voles do not nest there, and prune only to keep one leader.

The flowers are wind pollinated, and an acorn crop wants another oak nearby. As a red oak it can catch oak wilt where that disease occurs, so prune only in the dormant season, to avoid the beetles that spread it. Anthracnose, cankers, leaf spots and powdery mildew can show up, but the damage is seldom serious. Acorns begin once the trunk is about 2 inches thick, and nearly every tree bears.

Heights and zones are typical ranges for the species in cultivation; local conditions and seed source shift them.

Sources (11)