Culture
Easily grown in average, medium, well-drained soil in full sun to part shade. Prefers moist loams, but tolerates a wide range of soils and has good drought tolerance. Prune as needed immediately after flowering, however pruning off spent flowers will eliminate summer fruit display, which admittedly is not very showy for this hybrid. For best cross-pollination and subsequent fruit display, plant shrubs in groups rather than as single specimens. This shrub is not reliably winter hardy in the St. Louis area where it should be planted in a protected location.
Noteworthy Characteristics
Viburnum × carlcephalum, commonly called fragrant viburnum or fragrant snowball, is an open, rounded, multi-stemmed, deciduous shrub which typically grows 6-10' tall and as wide. Features fragrant white flowers arranged in dense, snowball-like clusters (cymes 3-5" wide) in late April to early May. Blooms later than most viburnums. Flowers are followed by clusters of red berry-like drupes which ripen black. Fruit is not particularly showy. Ovate, grayish-green leaves (to 4" long) turn reddish-maroon in fall. This hybrid is a cross between V. carlesii and V. macrocephalum var. keteleeri.
Genus name comes from the Latin name of a species plant.
Specific epithet is a combination of the specific epithets of the two parents.
‘Cayuga’ was registered and released into commerce by The United States National Arboretum in 1966. It is a backcross of V. carlesii x V. x carlcephalum. It is particularly noted for its compact habit, abundant snowball inflorescences and dark green foliage. This is a moderately compact, deciduous shrub with spreading branches that typically grows 4-6’ tall, but over time will mature to as much as 8’ tall and 11’ wide. Pink buds give way to mildly fragrant, white waxy flowers in snowball inflorescences (cymes to 4” diameter) that bloom profusely in late April to May. Buds and open flowers are often seen simultaneously on the same inflorescence. Leves turn orange-red (sometimes undistinguished) in fall.
Problems
No serious insect or disease problems. Some susceptibility to bacterial leaf spot and powdery mildew. Viburnum crown borer can cause stem dieback.
Uses
Good specimen. Shrub borders or foundations. Hedge.