Luzon viburnum is a tropical evergreen shrub hailing from the Philippines, known for its glossy, leathery leaves and fragrant white flowers that bloom in clusters. It thrives in the warm, humid environment under partial shade, often reaching up to 8–15 ft in height. The plant produces red to black berries, serving as a food source for wildlife and adding ornamental value.
I. Appearance and Characteristics
Viburnum luzonicum, the Luzon viburnum, is a species of flowering plant in the family Viburnaceae. It is native to southeast and south-central China, Taiwan, the Philippines, Vietnam, and the Maluku Islands.
Genus name comes from the Latin name of a species plant.
Specific epithet comes from Luzon, the largest and most populous island in the Philippines and home to the capital city of Manilla. The native range of this shrub includes this island.
Viburnum luzonicum is a large deciduous shrub with a dense mounded habit that typically grows to 8-15’ tall, but may occasionally reach 20’. Leaves (to 4” long) are elliptic-ovate to ovate-lanceolate to oblong. Leaves turn reddish-purple in fall and remain on the shrub until late winter before dropping as new growth begins to appear.
Small white flowers in compound umbel-like cymes bloom April-May. Flowers have a drab, slightly unpleasant fragrance. Flowers are followed by rounded fruits which mature to red in late summer to early fall, eventually turning black.
II. How to Grow and Care
Luzon viburnum is generally regarded as an easy-to-care-for shrub, well-suited for novices. Key to its thriving is ensuring it is planted in well-drained soil and receives adequate moisture without becoming waterlogged. A special care point for luzon viburnum is the necessity for regular pruning to maintain its shape and promote healthy growth. This plant thrives with minimal care, making it a desirable choice for gardeners of any expertise.
Sunlight
Luzon viburnum in a cold environment loves to grow in full sun on slopes and edging rocks in its natural habitat. Varieties adaptable to warmer climates grow well in full sun to medium shade; long exposure to strong light should be avoided. They can be shaded by buildings or big trees. A certain amount of scattered light is needed in the flowering phase to ensure enhanced and continuous flowering in warmer climates, but overall, plants in this genus perform well receiving 5-6 hours of continuous sunlight in a day.
Temperature
The optimum growth temperature range is between 5 to 27 ℃. It has good cold resistance; some native North American species can tolerate temperatures below -25 ℃. Its growth is poor at temperatures above 29 ℃, so it cannot survive in tropical summers. Germination requires 20 consecutive days of seed exposure to 24 ℃.
Luzon viburnum needs occasional watering during hot and dry conditions. The average plant during its first 2 years of growth needs 1.2 to 1.5 cm water bi-weekly. Once established, it doesn’t need much watering.
Watering
Originating from regions with intermittent rainfall, luzon viburnum has adapted to absorb and store water efficiently, displaying moderate drought tolerance. It thrives best when its soil moisture is kept consistent, without being overly saturated. For optimal hydration, luzon viburnum requires watering once every 1-2 weeks. As an evergreen plant commonly grown outdoors, luzon viburnum’s ability to maintain lush foliage is contingent on receiving adequate water during its active growth cycles.
Soil
Luzon viburnum likes fertile, soft, slightly acidic soil with good drainage. It likes moist soil but does not grow well in waterlogged soils. It can grow in moderately fertile, fully drained soils that keep minimum moisture, but cannot withstand poor soil. The optimum soil pH range is 5.5-6.6. It can tolerate acidic media and drought with good air circulation in the root zone, which is made possible by the addition of peat moss or coco coir to the media. The best potting soil would be to mix 1 part of fully decomposed organic matter into 2 parts of garden soil.
Fertilizing
For luzon viburnum, apply a balanced fertilizer annually at the onset of the growing season to encourage robust growth and flowering. Opt for slow-release formulations to provide consistent nutrients. During peak growth periods, enhance nourishment with a monthly diluted liquid fertilizer. Abstain from over-fertilizing to prevent root burn and environmental stress. Adjust fertilization practices in response to luzon viburnum’s life stages and seasonal changes, using less in the dormant winter period. Effective fertilization of luzon viburnum involves observing plant response and adhering to recommended dosages for optimal plant health.
Planting Instructions
The best time for transplanting is in late spring or early summer. It is best to plant them all on the same day. Take care that roots aren’t exposed to direct light and are buried deep into the planting pit.
Before planting, you need to know the height of a fully mature plant for the variety that you are growing. Generally, the role of thumb is to divide the height of the plant by 2 to determine space. For example, if the selected variety is predicted to grow 4 m tall at full maturity, space the plants 2 m apart. Dig a pit measuring 30 cm deep and 30 cm wide.
Pruning
Luzon viburnum should be pruned 1 to 2 times per year in late winter or early spring. This should be done before new growth begins in the spring, and approximately 1/3 of the longest branches should be pruned back to the desired height. This will help to keep the plant healthy and encourage new growth. Pruning luzon viburnum too much can damage the plant, so it’s important to exercise caution. In addition, thinning out overcrowded branches can help to improve air circulation, light penetration, and fruiting.
Propagation
Light pruning to remove dead or dried branches or injured parts of the plant can be done at any time of the year. Luzon viburnum doesn’t need severe pruning; how much depends on the type of variety and purpose of growing.
Pruning to shape and beautify can be done in the late winter or early spring. When growing for borders and hedges, cut only 1/3 of the branches if they are severely intermingled. In other cases, pruning can be initiated right after flowering but before the setting of fruit. To avoid frost damage, don’t prune during frost or severe cold.
Transplanting
For luzon viburnum, the dormant season, often known as winter’s rest, offers the perfect time to transplant, reducing stress on the plant. Choose a site with well-draining soil and partial shade. When relocating luzon viburnum, ensure root disturbance is minimal to promote swift recovery.
III. Uses and Benefits
Luzon viburnum is suitable for making shrub borders, screens, foundations or hedges.
