Rare Oak Collection

Why these five go together

This is a living collection rather than a hedge: five oaks that garden centers do not carry, from six-foot shrub oaks to an eighty-foot bottomland giant. Each is grown from seed off wild or proven parent trees. Dwarf chinquapin oak drops sweet acorns within a few years of planting. Bear oak is a scrub oak of pine barrens and one of the great caterpillar hosts. Sand post oak is a compact post oak of deep coastal-plain sand. Oglethorpe oak is among the rarest oaks in North America, with unlobed leaves and white-oak toughness. Delta post oak is a post oak that tolerates wet feet, from the bottomlands of the lower Mississippi.

Four of the five are white oaks. Bear oak is the red-oak-group exception, which matters for acorns and for disease. Together they cover the range of what an oak can be.

Where it fits

The collection needs two kinds of ground. Dwarf chinquapin oak, bear oak and sand post oak want full sun and dry, sandy or rocky soil. Oglethorpe oak and delta post oak want moist to wet bottomland. A property with a dry ridge and a damp flat can hold all five.

Hardiness is the honest limit: the two shrub oaks are hardy to zone 4, but sand post oak and Oglethorpe oak need zone 6 and delta post oak zone 7. The whole set fits together only in zones 7 and 8. North of that, plant the two shrub oaks and treat the three southern ones as trial trees in a sheltered spot. Sizes run from 6 to 20 feet for the shrub oaks and 15 to 40 for sand post oak up to 50 to 80 feet for the two bottomland oaks. Oglethorpe oak wants 30 to 40 feet from buildings, other large trees and overhead lines, and delta post oak 40 feet from the house and other big trees. Sand post oak needs 15 feet from a building, and the shrub oaks 10.

See the set's year in the bloom and fruit calendar, how many of each give a crop in the pollination planner, and how far its tallest plant goes from the house in the planting-distance tool.

Planting the collection

Plant small and dormant, with the flare at grade, and never bury the taproot deeper than it grew. Tube or cage every oak for three or four years. Deer and rabbits find young oaks before anything else. Water deeply once a week the first summer and in dry spells for two more.

Plant every oak in pairs, ten in all. Bear oak is the set's only red oak and will not set acorns from its own pollen, so it needs a second bear oak. For the white oaks a second of each makes the crop surer. A lone dwarf chinquapin oak sets a light crop, an isolated Oglethorpe oak sets fewer acorns, and sand post oak and delta post oak need pollen from another tree.

Dwarf chinquapin oak bears within a few years. Bear oak acorns take two years to ripen and come in heavy crops every other year. The tree oaks take decades to make a crop, which is the reason to plant them now. Keep the leaves under them: the caterpillars, the hairstreaks and the salamanders that make an oak worth having live in the litter.