Magnolia macrophylla in flower

M. ashei on East TN State Univ. campus in Johnson City, TN

Bigleaf magnolias are represented by four species: (M. macrophylla), umbrella magnolia (M. tripetala), Fraser magnolia (M. fraseri), and Ashe magnolia (M. ashei). All are medium-size trees with huge leaves and large flowers that appear after the leaves unfurl. All are native to the southeastern United States as far north to West Virginia and Ohio (USDA hardiness zones 5-8). A mature tree attains heights of 30 to 40 feet and matures into an irregular pyramidal tree habit. In the northern areas the tree is deciduous and semi-evergreen in the southeastern U.S.

Its enormous size foliage makes it a true horticultural oddity. Leaves are alternate, simple, 12 to 36 inches long and 7 to 12 inches wide. They’re bright green above and silvery gray below. Petioles are 2 to 4 inches long. Its yellow fall color rarely stands out.

Their large leaves decompose slowly and do create a litter headache. Their enormous leaf size relegates their plantings primarily to large properties and private woodlands where weak branches and unusual leaves are sheltered from ice and wind storms. Leaves are intolerant of most urban pollutants.

Here in Tennessee and North Carolina, all species grow in moist, humus-rich, well-drained mountain soils, and in full sun to partial shade. Established plants are only marginally drought tolerant. In the mountains, trees  closely associate their roots nearby a small creek or stream. Foliage is not tolerant of most urban pollutants. A tree may take 10 or more years before first blooms form. Goblet-shaped flowers are creamy white, rose-purple at the petal base, and measure a foot or more across. Flowers appear in late spring, high in the tree, and mostly hidden within the dense foliage. Up close, flowers are pleasantly fragrant.

Fruits (called “cones”) are round (cone-like), rose-colored, and nearly 3-inches long. Cones are unique, persistent, and attract numerous bird species. Cones open to reveal the red coated seeds, each one attached by a thin silk-like thread.

Large-leaved magnolias are primarily sold by a small number of native plant nurseries.

Fall color of M. macrophylla at Biltmore Estates in Asheville, NC.