Culture
Best grown in moist, acidic, humusy, organically rich, sharply-drained soils in full sun to part shade. Part shade locations often produce the best foliage color and a more open plant habit. Plants may spread by root suckers to form colonies if suckers are not promptly removed.
Noteworthy Characteristics
Fothergilla × intermedia, commonly called hybrid fothergilla or witch-alder, is a hybrid deciduous shrub whose parents are two American species, namely, F. major (6-10’ tall with leaves to 5” long) and F. gardenia (2-3’ tall with leaves to 2 1/4” long). F. × intermedia hybrids are intermediate in physical characteristics between the two parent species in terms of leaf size, inflorescence size and plant shape (height and spread). These hybrids are upright, multi-stemmed, deciduous shrubs that typically mature to 3-5’ tall and feature a prolific April-May bloom of bottlebrush-like spikes of fragrant, white, apetalous flowers. Flowers are monoecious, with male and female flowers appearing on the same spikes. Female flowers are not showy, but the male flowers feature ornamentally attractive stamens (bright white filaments and yellow anthers). Flowers appear before the leaves fully unfold. Stems are clad with ovate to obovate blue-green leaves (to 2-4” long) which typically produce excellent orange-red-yellow fall color.
The native ranges of the parent species do not overlap. F. major is a highland species native primarily to alpine areas in North Carolina, South Carolina, Georgia, Tennessee and Alabama. F. gardenia is a coastal species native along the coastal plain from North Carolina to the Florida panhandle and Alabama. Many nurseries in the SE U.S. once commonly grew the two species in close proximity on their own land. In the late 1970s, some of these nurseries began developing and marketing interesting new cultivars grown from open pollinated seed. These new cultivars were primarily chosen for their compact intermediate size, prolific bloom and long-lasting fall color. Initially the new cultivars were listed as cultivars of F. gardenia, but subsequent botanical testing and research revealed that the new plants were in fact hybrids between F. major and F. gardenia. As of 2007, × intermedia became generally accepted by many authorities as the chosen hybrid name.
Genus name honors Dr. John Fothergill (1712-1780), English physician and botanist who grew plants from around the world in his London garden.
The hybrid name intermedia is in reference to the hybrid characteristics being intermediate between the characteristics of the two parent species.
‘Blue Shadow’ was introduced by Handy Nursery in Oregon. It is a branch sport of F. ‘Mount Airy’, and is very similar to ‘Mount Airy’ in most characteristics except for its leaves which emerge green in spring but quickly mature to an intense, striking powder blue. Leaves retain good blue color throughout summer, eventually changing to often brilliant shades of red, orange and yellow in fall. US Plant Patent PP15,490 was issued on January 25, 2005.
Problems
No serious insect or disease problems.
Uses
Group or mass in shrub borders, foundation plantings, woodland margins or open woodland areas. Hedges. Mixes easily with rhododendrons which generally share the same soil requirements. Interesting specimen or accent.