Doublefile viburnum (Viburnum plicatum f. tomentosum 'Shasta')
Viburnum plicatum f. tomentosum 'Shasta' or Doublefile viburnum offers striking tiered branching and abundant white flowers, a low-maintenance, deciduous shrub.
Complete Plant Information
Overview
Viburnum plicatum f. tomentosum ‘Shasta’, commonly known as Doublefile viburnum, is highly valued by gardeners for its magnificent layered branching structure, which creates distinct horizontal tiers throughout the year. This specific cultivar showcases large, showy white flowers that bloom profusely from May through July, often following the tiered branches in a characteristic “doublefile” pattern. As a dense, upright, multi-stemmed deciduous shrub, Viburnum plicatum f. Tomentosum ‘Shasta’ provides excellent texture and structure in the landscape, maturing moderately large while remaining relatively easy to manage.
This shrub provides year-round visual interest, moving from dramatic spring blooms to attractive foliage structure, finishing with colorful fall fruit display. Its low maintenance requirements and adaptability to various soil types make the Doublefile viburnum an invaluable specimen plant or screen in temperate gardens. Gardeners appreciate its dependable performance across temperature fluctuations within its suitable hardiness range.
Fast Facts
- Plant Family: Adoxaceae
- Plant Type: Deciduous shrub
- Hardiness Zones: USDA Zones 5-8
- Size at Maturity:
- Height: 6-8 ft
- Spread: 9-12 ft
- Bloom Time: May to July
- Bloom Description: White
- Sun Exposure: Full sun to part shade
- Water Needs: Medium
- Maintenance Level: Low
How to Grow
Plant Viburnum plicatum f. tomentosum ‘Shasta’ during the cooler seasons—spring or fall—to allow root establishment before summer heat. Ensure it is sited in full sun to partial shade, matching its preference for receiving several hours of direct sunlight daily for optimal flowering. The Doublefile viburnum thrives in average, medium moisture, well-drained soil, though it performs best in moist loams where moisture is consistent.
Maintain medium water needs by providing consistent moisture, especially during dry spells, as this shrub significantly prefers even soil hydration. Fertilization is rarely necessary if the plant is sited correctly in rich soil; otherwise, apply a balanced, slow-release fertilizer in early spring. Pruning should be done judiciously, limiting removal to immediately after the main flowering period ends in July to avoid cutting off next year’s developing flower buds.
Handle Viburnum plicatum f. Tomentosum ‘Shasta’ with care regarding late winter protection, as early warm spells can prompt bud development which can then be damaged by subsequent hard freezes. Clean up spent foliage in autumn; however, appreciate the attractive burgundy red to purplish red fall color demonstrated by the strongly-veined, ovate leaves.
Landscape Uses
The structure of Viburnum plicatum f. tomentosum ‘Shasta’ makes it exceptional for use as a specimen where its tiered branching can be fully appreciated. It works beautifully when sited slightly away from buildings or competing plants to allow the horizontal habit to develop naturally. Its size also suits it well for use in shrub borders, providing substantial mid-layer structure against taller evergreens or background plantings.
As noted in its suggested use, the robust size and dense growth habit of the Doublefile viburnum make it an excellent choice when formal hedging is desired, though it requires less constant shearing than traditional hedging material. Plant Viburnum plicatum f. tomentosum ‘Shasta’ alongside early-blooming spring bulbs that die back before the Viburnum reaches its full summer canopy, ensuring multi-seasonal interest in the border.
Standout Features
Flower Qualities
- Showy
Fruit Qualities
- Showy
Noteworthy Characteristics
Viburnum plicatum is a dense, upright, multi-stemmed, deciduous shrub that typically matures to 8-15’ tall with a slightly larger spread. Ovate, toothed, strongly-veined, dark green leaves (to 4” long) have pleated upper surfaces. Leaves turn burgundy red to purplish red in fall. Two different forms of this shrub are commonly sold in commerce: (1) Japanese snowball bush (f. Plicatum) which is the type form featuring sterile, snowball-like, orbicular inflorescences (2-3” diameter cymes) of non-fragrant, showy white flowers along the branches in spring with no subsequent fruit and (2) doublefile viburnum (f. Tomentosum) which is the wild-related taxon featuring fertile, flat-topped flower clusters (2-4” diameter cymes) which bloom along tiered horizontal branches in doublefile form, each cluster containing an outer ring of large showy sterile florets surrounding a center mass of tiny non-showy fertile florets which when fertilized give way to egg-shaped fruits and viable seed. Bloom time of f. Plicatum typically occurs about two weeks later than that of f. Tomentosum. Mature height of f. Plicatum may rise to as much as 15’ tall, but mature height of f. Tomentosum typically will not exceed 10’ tall. Except as to flower structure, bloom time, height and branching habit, both forms are otherwise very similar and commonly sold in commerce under a number of different cultivar names. The sterile snowball form (f. Plicatum) is known from cultivation only (first observed as a garden plant in Japan). It was discovered prior in time to the discovery of the wild fertile doublefile form (f. Tomentosum) from which it was actually developed. As a result of this inverted schedule of discovery, the sterile form was mistakenly given a species name (Viburnum plicatum) and the subsequently discovered fertile form (f. Tomentosum) was named as if it were a variety of the species. The wild form (f. Tomentosum) is native to forests and thickets in China and Japan. Forma tomentosum has fine hairs on young stems and leaf undersides.Genus name comes from the Latin name of a species plant.Specific epithet means pleated or folded in reference to leaf veins.‘Shasta’ is a cultivar that typically matures to 6-8’ (sometimes to 10’) tall and spreads to 9-12’ wide. This is a large shrub that produces abundant flowers in spring on horizontal branches followed by abundant red maturing to black fruits. Large flower clusters (each to 6” wide) feature showy outer snow-white sterile flowers (each to 2” wide). Introduced in 1979 by the U.S. National Arboretum
Tolerances
- Tolerates a wide range of soils beyond moist loams.
Potential Problems
No serious insect or disease problems are typically encountered when growing Doublefile viburnum. Gardeners should be aware that squirrels are occasionally known to consume unopened flower buds during late winter, which can significantly reduce or eliminate the expected spring bloom display.
To manage this potential issue, consider netting critical specimen plants temporarily during the late winter months when squirrels are actively foraging, or ensure planting locations are situated where squirrels are less likely to congregate. Consistent care, especially avoiding drought stress, helps maintain overall plant vigor, naturally deterring secondary pest issues.
Frequently Asked Questions
What hardiness zones is Doublefile viburnum suitable for?
Viburnum plicatum f. tomentosum ‘Shasta’ is hardy in USDA Zones 5 through 8, allowing for successful cultivation across a wide portion of the country.
How large does Doublefile viburnum grow?
This cultivar typically reaches a mature height between 6 and 8 feet tall, with a spread ranging from 9 to 12 feet wide, developing a distinctly broad, layered habit.
When does Doublefile viburnum bloom?
The beautiful white flowers of Viburnum plicatum f. Tomentosum ‘Shasta’ appear during the late spring to early summer, specifically blooming from May to July.
What sun exposure does Viburnum plicatum f. tomentosum ‘Shasta’ need?
This shrub adapts well to conditions ranging from full sun to partial shade, though placement in full sun usually results in the most abundant flowering display.
Conclusion
The Viburnum plicatum f. tomentosum ‘Shasta’ stands out as a spectacular, low-maintenance deciduous shrub celebrated for its distinctive horizontal branching and abundant white summer flowers. For gardeners seeking reliable seasonal structure and beautiful blooms, the Doublefile viburnum is an excellent selection. Always confirm your local hardiness zone compatibility before planning the location for your new planting.
Companion Planting
When selecting companions, focus on plants that share similar cultural requirements, thriving in medium moisture and partial shade, which complements the Doublefile viburnum’s needs. Consider pairing it with acid-loving shade perennials such as Astilbe or Hosta varieties that have good sun tolerance, as their textures and colors contrast beautifully with the Viburnum’s bold, pleated leaves. Planting ferns or groundcovers beneath the canopy of Viburnum plicatum f. tomentosum ‘Shasta’ will help shade the soil, maintaining the consistent, even moisture that this shrub prefers throughout the growing season.
Design Ideas for Tiered Shrubs
The unique, tiered branching habit of Viburnum plicatum f. Tomentosum ‘Shasta’ should inform its placement to maximize its architectural beauty, especially during winter when leaves have dropped. Use it as a transitional planting between tall evergreen screens and lower foundation plantings, allowing the tiered layers to flow naturally outwards. For smaller yards, showcasing a single specimen of this Doublefile viburnum allows its form to command attention, eliminating the need for dense mass plantings that might obscure its structure.
