Korean spice viburnum (Viburnum carlesii), is a deciduous flowering shrub with wonderfully aromatic flowers. It grows in USDA plant hardiness zones 4 through 7 and makes a great specimen plant for spring blossoms.
Korean Spice Identification
Plant taxonomy classifies Korean spice viburnum shrubs as Viburnum carlesii, while their common name is Korean spicebush. However, be careful not to confuse this with "spicebush" (Lindera benzoin) or "California allspice" or California spicebush" (Calycanthus occidentalis). Viburnum carlesii are in the moschatel family of plants, which also includes elderberry (Sambucus). A popular cultivar is 'Aurora.'
Korean spice viburnum shrubs reach 4 to 6 feet in height at maturity, with a similar spread. The 'Compactum' cultivar is sometimes referred to as a "dwarf" type because it stays a bit smaller (3 to 4 feet). The flowers start as pink buds and change to white blooms with a hint of the early pink color. The white flower clusters are nicely rounded and very fragrant.
Flowers on Korean spicebush are replaced by red berries in summer, provided a compatible cross-pollinator is present. In other words, these bushes are not self-pollinating. In autumn, the berries mature to a dark, almost black color. But if you are looking forward to fall color, count more on the fall foliage of the leaves than on the berries. In the opinion of Ohio State University, the berries (drupes) are usually "ornamentally insignificant." The fall leaves start out reddish but can morph into a purplish color.
If you still wish to try for berries, you will be faced with the cross-pollination problem, which is twofold:
- The pollinator plant cannot be of the same cultivar. So, for example, you cannot pollinate an 'Aurora' with another 'Aurora.' Instead, you would have to pair your 'Aurora' with another viburnum from the same species (a hybrid bred from the same species will also work).
- The pollinator plant must also come into bloom at the same time as the plant from which you are trying to get berries. Because plants bloom at different times in different areas, ask local nurseries or an extension service to recommend a suitable pollinator.
One possibility is to pair a V. carlesii with a V. x burkwoodii 'Mohawk,' since the latter is a hybrid cultivar, with one of the parents being V. carlesii. But before you buy, inquire at the garden center as to whether the two plants come into bloom at the same time in your area. Better yet, if you will be shopping for the two at the same time, buy them only if both are blooming.
Growing Korean Spicebush
Buds for Korean spice viburnums form on the prior season's growth. Therefore, if you wish to prune the plants back in order to shape them and/or restrict their size, do your pruning just after they have finished flowering. Just cut the tips to promote branching and a bushier look. In addition, remove any dead branches and/or branches rubbing against each other.
One problem you may experience in caring for this bush is leaf curl (at the tips of branches). The culprit will most likely be aphids. If you can manage to catch the little buggers in action, you can spray them with the organic herbicide Neem oil. But aphids can come and go very quickly, leaving a damaged leaf behind. Luckily, leaf curl, if restricted to just a relatively small portion of the entire plant, does no long-term harm. It is problematic only on an aesthetic level, marring the appearance of the foliage during that summer and fall. Prune off the affected branch tips and dispose of them properly, and the plant will be none the worse for it.
Uses for Korean Spicebush in the Landscape
No doubt, the single most outstanding feature of Korean spice viburnum shrubs is their aromatic quality. Another plus is that these plants are among the flowering shrubs that bloom in early spring, satisfying our craving to see landscape color as soon as possible once winter ends. Honorable mention goes to the color of their fall foliage. In fact, they are undoubtedly one of the best shrubs for fall color.
Korean spice viburnum bushes certainly merit specimen plant status in the spring landscape. Due to their exceptional fragrance, you should include these bushes in your entryway landscaping or as foundation shrubs to fully appreciate their aroma.
Wildlife Attracted to Korean Spice Viburnum Shrubs
These bushes are among the many plants that attract butterflies. Specifically, the caterpillars of spring azure blue butterflies use Korean spice viburnums as a food source. Wild birds are also attracted to the shrubs, to feed on the berries (if present). As to a certain unwanted visitor from the Animal Kingdom, one can list them among the rabbit-proof flowers with some confidence.