Koreanspice viburnum (Viburnum carlesii 'Diana')
Viburnum carlesii 'Diana' offers immensely fragrant white flowers in spring. A low-maintenance Koreanspice viburnum for zones 4-7.
Complete Plant Information
Overview
The Koreanspice viburnum, specifically the cultivar Viburnum carlesii ‘Diana’, is prized by gardeners primarily for its incredibly fragrant blooms that herald the arrival of warm weather. This vigorous cultivar maintains a compact, rounded habit, making it perfect for smaller spaces where its aesthetic and aromatic qualities can be fully appreciated. While its stature is dependable, reaching 4 to 6 feet tall and wide, it requires surprisingly little effort to maintain its good structure.
This deciduous shrub offers more than just its signature early spring show. The flowers transition from pink buds to pure white clusters, adding multi-season interest alongside reliable green summer foliage. For gardeners seeking low maintenance coupled with high impact, Viburnum carlesii ‘Diana’ serves as an excellent choice for borders, specimen planting, or mixed shrub groupings.
Proper placement in full sun to partial shade will ensure the best flowering display for your Koreanspice viburnum. Its ability to thrive with medium water input and generally low fuss cements its status as a garden staple for those in USDA Zones 4 through 7.
Fast Facts
- Plant Family: Adoxaceae
- Plant Type: Deciduous shrub
- Hardiness Zones: USDA Zones 4-7
- Size at Maturity:
- Height: 4-6 ft
- Spread: 4-6 ft
- Bloom Time: March to April
- Bloom Description: White
- Sun Exposure: Full sun to part shade
- Water Needs: Medium
- Maintenance Level: Low
How to Grow
Planting Viburnum carlesii ‘Diana’ is best achieved in the spring or fall when temperatures are moderate. Choose a location that receives full sun to light afternoon shade; too much deep shade may reduce flowering potential. This shrub thrives in average, medium soils, provided they are well-drained. Amending heavy clay soils to improve drainage is crucial for long-term health, as standing water is detrimental.
Once established, care is minimal. Water medium requirements mean regular irrigation during initial establishment or extended dry spells, but established plants are reasonably drought tolerant. Avoid heavy fertilization; if needed, apply a slow-release fertilizer in early spring before new growth begins. Weeds can be managed with a light layer of organic mulch, keeping it pulled slightly away from the main stem crown.
Pruning should be executed with care. Since the flower buds for the following year form during the summer, any substantial shaping must happen immediately after the current season’s flowers fade in late spring. Delaying pruning until late summer or fall will result in the removal of next year’s bloom on your Koreanspice viburnum.
Landscape Uses
The primary appeal of Viburnum carlesii ‘Diana’ lies in its exceptionally fragrant flowers, making it ideal for planting near patios, entryways, or along frequently used paths. Its attractive, shrubby nature lends itself perfectly to use as a foundation planting, softening harsh architectural lines. Plant in groups to create an immersive experience when the shrub is in full bloom.
This versatile deciduous shrub also performs admirably in mixed shrub borders, interplanted with slightly later-blooming varieties to extend seasonal interest. While it can be grown as an informal hedge, its natural rounded shape is best left unclipped to maximize flower production. The dark green summer foliage provides a lovely backdrop for spring-flowering bulbs planted at its base.
Foundation planting or shrub borders are excellent applications for the Koreanspice viburnum. Consider mixing Viburnum carlesii with evergreen broadleaf shrubs or contrasting textures like ornamental grasses that appreciate the same sun and water conditions.
Standout Features
Flower Qualities
- Showy
- Fragrant
Noteworthy Characteristics
Viburnum carlesii commonly called Koreanspice viburnum is a slow-growing, upright, rounded, deciduous shrub which typically matures to 4-5’ tall but may reach a height of 8’ in optimum growing conditions. Red buds open in late March/early April to pink-changing-to-white flowers which are arranged in snowball-like clusters (hemispherical cymes) to 3” across. The foliage often features dull red fall color, providing seasonal variation beyond the renowned spring bloom of the Koreanspice viburnum.
Tolerances
- Black Walnut
Potential Problems
Occasional issues with Viburnum carlesii ‘Diana’ may include bacterial leaf spot and powdery mildew, often encouraged by poor air circulation or excessive overhead watering. Ensure good spacing between plants. Pest pressure is usually low, though viburnum crown borers can sometimes be an issue; watch for wilting symptoms indicating borer activity. Armillaria root rot is a serious concern, particularly in poorly drained sites, emphasizing the need for excellent soil drainage during planting.
Frequently Asked Questions
What hardiness zones is Koreanspice viburnum suitable for?
Viburnum carlesii ‘Diana’ is generally hardy and suitable for planting in USDA Zones 4 through 7.
How fast does Viburnum carlesii ‘Diana’ grow?
This cultivar is described as slow-growing, typically maturing between 4 to 6 feet high, though it can reach up to 8 feet in ideal growing situations.
When does Koreanspice viburnum bloom?
The highly fragrant flowers of the Koreanspice viburnum perfume the garden in early spring, blooming from March into April, starting as pink buds before opening white.
What sun exposure does Viburnum carlesii ‘Diana’ need?
This shrub performs best when situated where it receives full sun or partial shade, offering flexibility in landscape placement.
Conclusion
The Viburnum carlesii ‘Diana’ stands out as a superior choice due to its exceptionally fragrant spring flowers and reliably low maintenance requirements. For gardeners seeking high impact with minimal fuss, this cultivar of Koreanspice viburnum is an excellent investment. Before planting, confirm that your location falls within USDA Zones 4-7 and ensure your soil drains well to guarantee years of enjoyment.
Companion Planting
When selecting companions for Viburnum carlesii ‘Diana’, prioritize plants that share similar cultural needs—medium water requirements and tolerance for full sun to part shade. Pairing it with early-blooming spring bulbs like daffodils or tulips creates a beautiful layered effect, as the bulbs will fade just as the viburnum reaches its peak. For contrasting foliage texture, consider companion plantings such as Japanese forest grass (Hakonechloa macra) in shadier spots, or low-growing hostas that tolerate some morning sun.
Seasonal Care Calendar: Year-Round Tips
Spring is the critical maintenance window; prune Viburnum carlesii ‘Diana’ immediately after flowering concludes to shape the shrub and ensure next year’s blooms are not accidentally removed. Apply a light layer of balanced fertilizer just as early growth begins, if soil tests indicate a need. Summer care focuses on consistent medium watering, especially during heat waves, and applying a fresh layer of mulch to conserve moisture and suppress weeds. In autumn, monitor the foliage for seasonal color changes; fall watering should be maintained until the ground freezes to ensure the roots are hydrated going into winter dormancy. Minimal pruning or cleanup is required in winter, focusing solely on removing any obviously dead or damaged wood.
