Photo: Homoarborea, CC0 · Wikimedia Commons

Maple-leaf Oak

Quercus acerifolia

Also called maple-leaved oak, mapleleaf oak, Quercus shumardii var. acerifolia.

A rare red oak of a few Arkansas mountaintops, with broad leaves shaped like a sugar maple's that turn red in fall.

Type: Small tree
Mature height: 20–50 ft
USDA zones: 5–9
Growth rate: Slow
Sun: Full
Soil moisture: Dry, Average
Grows wild in: Rocky ground and dry uplands
Native range: Arkansas See what is native in your state

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Maple-leaf oak grows wild on a handful of dry, rocky ridgetops in west-central Arkansas, on Magazine, Porter, Pryor and Sugarloaf mountains. NatureServe ranks it critically imperiled, and the IUCN Red List rates it Endangered. The Wildflower Center reports it listed as threatened by the state of Arkansas. Its finder, E. J. Palmer, first described it in 1927 as a variety of Shumard oak. Grow it as a small shade tree on a dry, open site, or as the centerpiece of an oak collection.

Size, growth and what to expect

A tree raised from Arkansas seed at the Sir Harold Hillier Gardens in England stood 17 feet at 17 years and 24 feet at 28. That is about a foot a year, the slow class of our growth estimator. Garden trees reach 40 to 50 feet, with a spread of 20 to 30. On Mount Magazine the biggest wild tree stands about 20 feet.

It flowers from March to May, and as a red oak it ripens its acorns at the end of the second season. Collectors have gathered them from mid-September on Mount Magazine and nearby peaks, and some ripen as late as November. The acorns are about three quarters of an inch long, a quarter to a third in a shallow cup. Palmer's own acorns grew into a tree at the Arnold Arboretum, and a seedling of it planted at the Morton Arboretum in 1950 is thought the finest in cultivation. A tree in France raised from 2011 seed bore its first acorns in 2020.

How to grow Maple-leaf Oak

Maple-leaf oak wants full sun and an average to dry, well-drained soil, and it takes drought well once rooted. On Mount Magazine, trees overtopped by taller growth have died back in the crown. Set trees 20 feet apart, and keep each one 15 feet from a wall and more than 50 feet from overhead wires.

Saplings ship bare-root or potted. Plant them dormant, from leaf fall until bud swell, in a hole wider than the roots and no deeper. Set the root flare at the soil line, put the soil back in, and keep the mulch clear of the trunk. Red oak acorns need a winter's chill before they sprout. Sow them in fall an inch deep under hardware cloth. For spring, hold them damp in the refrigerator for four to twelve weeks first. Never let them dry out, since acorns die when dried.

Water every week or two through the first summer, then only in a long drought. Deer and rabbits browse young oaks, so guard each sapling with a tube or cage for its first three years. It often grows several trunks from the base, so keep one leader for a single trunk or let it stay multistemmed.

The flowers are wind pollinated, and an acorn crop wants another oak nearby. As a red oak it can catch oak wilt, so prune only in the dormant season, to avoid the beetles that spread it. Wild trees have long set few sound acorns, with gall wasps that damage the seed, heat and drought to blame. Otherwise it is durable and long-lived.

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

Sources (11)