Viburnum rhytidophyllum aka Leatherleaf Viburnum

Viburnum rhytidophyllum is native to central and western China. It naturally grows in mountainous regions and woodland areas of its native range. The species was introduced to Western cultivation in the early 1900s and has since become a popular landscape shrub in temperate gardens worldwide.

Viburnum rhytidophyllum is cold hardy to USDA zones 5-8, tolerating winter temperatures down to approximately -20°C (-4°F). The RHS rates it H6, meaning it's hardy throughout the UK and northern Europe. In colder regions (zone 5), the evergreen foliage may suffer winter damage and the plant can become semi-deciduous.

Viburnum rhytidophyllum produces flowers with a mild, subtle fragrance. Unlike the famously fragrant Korean Spice Viburnum, the leatherleaf viburnum's scent is not a standout feature. Morton Arboretum describes the blooms as having slight fragrance. The plant is primarily grown for its distinctive wrinkled evergreen foliage rather than its floral scent.

Viburnum rhytidophyllum blooms in late spring (April-May) with creamy white flowers arranged in flat-topped to slightly domed clusters measuring 4-8 inches across. Individual flowers are small, about 1/4 inch wide, with five petals and prominent stamens. The flower buds form in late summer of the previous year and remain visible through winter. Flowers are followed by red berries that mature to glossy black by autumn.

Viburnum rhytidophyllum flowers are pollinated by insects, particularly bees and butterflies. The plant is noted as butterfly-friendly. Importantly, this species requires cross-pollination with another viburnum variety to produce its ornamental red-to-black berries. Suitable pollination partners include other V. rhytidophyllum plants, hybrid cultivars like Alleghany or Willowwood, V. lantana, or V. pragense.

Several cultivars and hybrids are available. Pure V. rhytidophyllum cultivars include Cree (compact form), Green Trump, Roseum (pink-tinged flowers), and Variegatum (variegated foliage). The hybrid V. rhytidophylloides (cross with V. lantana) offers Alleghany with dense dark-green foliage and Willowwood with an elegant arching habit. Little Snowball is a compact patented variety. These hybrids are semi-evergreen and slightly hardier.

Yes, Viburnum rhytidophyllum is an outdoor landscape shrub hardy in USDA zones 5-8 (UK hardiness H6). It excels as a hedge, screen, specimen plant, or in mixed shrub borders. Plant in a location protected from strong winter winds to prevent foliage damage. In colder zone 5 gardens, the plant may become semi-deciduous in winter. It tolerates full sun to full shade, making it versatile for various garden situations.

Prune Viburnum rhytidophyllum immediately after flowering in late spring or early summer. The RHS classifies it as Pruning Group 8, meaning minimal pruning is needed - just remove dead, damaged, or crossing branches. Since flower buds form in late summer for the following year, pruning later in the season will reduce next year's bloom. For overgrown plants, rejuvenation pruning can be done by cutting back hard.

The most reliable method is semi-hardwood cuttings taken in summer. Take 8-10 inch cuttings from vigorous shoots after flowering, remove lower leaves, dip in rooting hormone, and plant in perlite or similar medium. Keep moist under dappled shade for 4-6 weeks until rooted. Seeds require both warm stratification (2 months) followed by cold stratification (3 months) before germinating. Layering in spring is also effective.

The main pests are aphids and viburnum beetle, which can defoliate plants. NC State also mentions purple mite infestations. Diseases include honey fungus (serious), grey moulds (Botrytis), leaf spot, and Phytophthora root rot. In humid conditions, powdery mildew may occur. Winter damage to foliage is common in cold climates. Generally has no serious pest problems when planted in appropriate conditions with good air circulation.

Brown leaves on leatherleaf viburnum are most commonly caused by winter damage, especially in colder zones or exposed locations. Cold winds and temperatures below -10F can cause foliage to brown and die back. Brown leaf edges may indicate drought stress or wind burn. Fungal leaf spot diseases can cause brown spots. To prevent browning, plant in a sheltered location and ensure adequate moisture during dry periods.

While classified as evergreen, Viburnum rhytidophyllum can become semi-deciduous in colder climates. Morton Arboretum notes that in northern climates it will lose its leaves in late autumn. This is normal behavior in zone 5-6 gardens, especially during harsh winters. Excessive leaf drop during growing season may indicate stress from drought, waterlogging, or root problems. The plant typically recovers and regrows foliage in spring.