Fothergilla x intermedia ‘Blue Shadow’ at Duke Gardens

Fall color of F. gardenia

In the Eastern U.S. two species, dwarf fothergilla (F. gardenii) and large fothergilla (Fothergilla major), are native. They are also labeled “witch alder”. Both species appear almost identical, except for flower and leaf size, and overall shrub size. Large fothergilla is indigenous to the mountain and Piedmont Regions of the Carolinas where soils are drier and slightly more acidic soil. It is also rated more winter hardy (zones 4-8) and prefers partial shade areas.

Fothergillas are four-season shrubs, members of the witchhazel family (Hamamelidaceae). Leaves are almost identical. Both species bloom abundantly with clean blemish-free summer foliage and superb fall color. Flower buds form atop terminal tips of branches.

Creamy white bottle-brush flowers, 1½ to 3-inch tall, appear in April to early May depending on the region of the country where you garden in. Flowers typically last 10 to 14 days and flowers emit a sweet honey scent. Summer foliage is usually blemish-free green to blue-green. Fall leaf color is variable from one year to the next from yellow, bright orange, or deep red. Weather and growing conditions play a role in fall colors each year.

Fothergillas prefer moist, humus-rich, well-drained, acidic soil; it lingers or dies in poorly drained soil. Shrubs tolerate partial shade, but flower numbers and shrub density are best in full sun. Root suckers form into a tight plant colony which widens over time.

Fothergillas are utilized as single specimen shrubs or plant several together as a shrub border, foundation planting or low hedge. Pruning is rarely needed for this slow growing compact shrub. They are not troubled by insect, disease, or deer browsing.

Leading Cultivars:

‘Mount Airy’ is a natural hybrid discovered at Mount Airy Arboretum in Cincinnati, Ohio by Dr. Michael Dirr of the University of Georgia; it grows 4 – 6 feet tall with good fall color and larger flowers (than dwarf fothergilla), and is more drought and winter cold tolerant (zone 4).

‘Blue Mist’ (F. gardenii) is a compact, 2-3 feet tall, slow-growing cultivar with a mounded habit; frosty blue-green summer foliage under moderate shade; subpar fall color in zone 7 and points south.

‘Blue Shadow’ (F. x intermedia) is a compact, 4-6 feet with striking powder blue (glaucous) foliage.