Viburnum sargentii is a broadleaf deciduous shrub with green foliage and white flowers in spring followed by red fruit. Attractive to bees, butterflies and hummingbirds. To grow well, it prefers sun – mostly shade and even moisture water. Grows happily in well-drained and average soil.
I. Appearance and Characteristics
Viburnum sargentii is a species of flowering plant in the family Adoxaceae (formerly Caprifoliaceae), native to north eastern Asia. Growing to 3 m (10 ft) tall and broad, it is a substantial deciduous shrub with 3-lobed, maple-like leaves, often turning red in autumn. Flat white flower-heads (cymes) resembling those of lacecap hydrangeas are borne in early summer. The outer florets are saucer-shaped and sterile, while the central tubular flowers are fertile. The flowers are followed in autumn by globose red berries.
The specific epithet sargentii commemorates the American botanist Charles Sprague Sargent.
The cultivar ‘Onondaga’, with red central flowers, has gained the Royal Horticultural Society’s Award of Garden Merit.
II. How to Grow and Care
Asian guelder rose is recognized for its straightforward maintenance requirements, suitable for gardeners of various experience levels. Key care points include placing asian guelder rose in an area with full sun to partial shade and ensuring it has well-drained, moist soil. Special attention should be given to provide asian guelder rose with adequate water during dry spells, particularly when establishing. Pruning asian guelder rose is also a consideration to maintain its shape and encourage healthy growth.
Sunlight
Asian guelder rose in cold environments 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 ℃.
Asian guelder rose 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 moderate moisture, asian guelder rose has adapted to a balance of hydration, tolerating brief periods of dryness. Its water habits reflect its resilience, preferring consistent but not excessive moisture. Accordingly, it thrives with watering once every 1-2 weeks. As an outdoor plant often subject to the whims of natural precipitation, asian guelder rose is adept at managing water intake during its active growing season to optimize health and vitality.
Soil
Asian guelder rose 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
Fertilize asian guelder rose in early spring with a balanced fertilizer to promote vigorous growth and abundant flowering. Apply every 4-6 weeks throughout the growing season, stopping in late summer to avoid new growth damage from frosts. Use prescribed amounts; typically, 2-3 ounces for young plants, and 3-6 ounces for mature ones per square yard, avoiding direct contact with stems. Monitor growth patterns to adjust feeding schedules and quantities. Over-fertilization risks foliage at the expense of blooms. Light feeding in autumn with a phosphorus-rich mix supports root health over winter.
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
Light pruning to remove dead or dried branches or injured parts of the plant can be done at any time of the year. Asian guelder rose 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.
Propagation
Asian guelder rose can be effectively propagated through cuttings. To achieve the best results, choose healthy, non-flowering shoots and prepare them by making a clean cut below a node. Treat the cut end with a rooting hormone to encourage root growth and plant it in a moist, well-draining soil mix. Ensuring a suitable environment with adequate humidity and warmth, the cutting will develop roots, making it ready for transplanting into a more permanent location.
Transplanting
The prime time to transplant asian guelder rose is in the verdant expanses of mid to late spring, ensuring root establishment before the heat of summer. Choose a location with dappled sunlight and well-draining soil to enhance asian guelder rose’s vigor post-transplant.
