The care information provided in this section represents the kind of practical advice is available for all the plants in this web site if you subscribe to the monthly customized newsletter Yardener’s Advisor.
Viburnum care is essential for maintaining these beautiful shrubs in your garden. While viburnums are relatively low-maintenance, caring for viburnum properly will ensure they thrive. From watering and fertilizing to pruning and mulching, following simple care guidelines can help keep your viburnum healthy and vibrant throughout the seasons.
Watering
Viburnums do not usually need watering except when they're first planted, in time of drought, or in late fall before the ground freezes for the winter. If you do water, give your plants 1 gallon of water twice a week or run your drip irrigation system or sprinkler for 20 to 30 minutes twice a week. Older shrubs need watering only during severe drought.
For more information see file on About Watering Equipment.
Fertilizing
These shrubs need only one yearly application of bagged sludge, a granular fertilizer with a slow release form of nitrogen, or compost. In the fall, spread a 10-10-10 viburnum
fertilizer on the soil to 1-1/2 feet beyond the tips of the branches (drip line). You may wish to supplement the fall feeding with 2 or 3 monthly snacks in late spring and early summer. Use a light side dressing of granular fertilizer or apply a foliar spray of dilute liquid fertilizer over all the leaves of the plant.
When it comes to viburnum care, applying a yearly application of a slow-release viburnum fertilizer ensures healthy growth. Regular feeding during late spring and early summer is another key aspect of caring for viburnum, promoting vigorous blooms and strong shrubs.
For more information see file About Fertilizers.
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Mulching
Viburnums do best when they have a 2- to 4-inch layer of organic mulch over their root zone all season long. Keep the mulch about 6 inches away from the trunk to avoid decay and rodent damage. Use chopped leaves, pine needles or wood chips to mulch viburnum. Avoid mulching with un-chopped leaves because they mat together, preventing water from getting into the soil. Peat moss makes poor mulch, because it draws water from the soil like a wick and is difficult to rewet when dry.
For more information see file on Using Mulch.
Pruning/Grooming
Healthy specimens rarely need pruning. Prune Viburnums after flowering only if pruning is necessary for shaping. Old or crowded plants may be thinned and shortened to bring flowers to eye level. After 4 to 5 years you may remove 1/3 of the oldest stems, and thereafter prune every 2 or 3 years. For a more formal effect, it is possible to train Viburnums to a single trunk. Choose the healthiest and most upright stem when young and keep side shoots pinched until it reaches the height you want. Then allow the plant to branch from the top.
For more information see files on Pruning Shrubs and Choosing Pruning Tools
By understanding the fundamentals of viburnum care, including watering, fertilizing, and pruning, you'll find that caring for viburnum becomes a simple and fulfilling part of your gardening routine.
Common FAQs about Caring for Viburnum
What is the best fertilizer for viburnum?
The best fertilizer for viburnum is a slow-release, balanced formula. Use products like Espoma Plant-Tone, Sunniland 6-6-6, or Osmocote to provide essential nutrients. Apply fertilizer at least two to three times during the growing season, with the first application in early spring to promote healthy blooms. If your soil is alkaline, opt for an acidified fertilizer, and consider mulching with peat moss around the root zone to help acidify the soil.
When to fertilize viburnum?
The best time to fertilize viburnum is in early spring, just before new growth begins, and again in late fall, after the leaves drop. Early spring fertilization encourages strong blooms and foliage as the threat of frost passes. Late fall fertilization supports root growth and prepares the plant for winter. Avoid fertilizing in late summer or early fall, as this can promote tender new growth vulnerable to frost damage.
For fertilization, use a balanced, slow-release fertilizer like 10-10-10 or 20-20-20, or organic options like Espoma’s Holly Tone. Apply the fertilizer evenly around the base of the plant, ensuring it doesn't touch the trunk, and water it in well. Follow package instructions for the right amount.
What are the water requirements for viburnum?
Viburnums prefer moist, well-drained soil but do not tolerate waterlogged conditions. Newly planted viburnums require frequent watering, about every 1-2 days when the top inch of soil is dry. Established viburnums are more drought-tolerant and generally need watering once a week or more often during dry spells. Always water deeply at the base of the plant to ensure the root zone is well-soaked.
For best results, water in the morning to allow the leaves to dry before nightfall and apply mulch around the base to help retain moisture. If your viburnum shows signs of underwatering, like droopy or greyish leaves, increase watering frequency. Established viburnums are especially drought-tolerant, such as Viburnum tinus and Viburnum odoratissimum, but always adjust watering based on weather conditions.
How do I do viburnum pruning?
Pruning viburnum is essential for maintaining its shape and health. Generally, viburnums need light pruning after flowering to remove spent blossoms, and more extensive pruning in late winter or early spring to maintain structure and promote healthy growth. Follow these steps to prune your viburnum effectively:
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After Flowering:
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Lightly prune spent flowers and any branches that spoil the shape of the shrub.
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Maintain the overall shape of the plant.
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Late Winter/Early Spring:
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For more significant pruning, cut back about a third of the plant’s branches each year.
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Remove old, damaged, or crowded branches to improve air circulation and keep the shrub open.
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Suckers:
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Remove suckers (new shoots emerging from the ground) during the growing season.
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Pruning Techniques:
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Maintenance Pruning: Cut back branches just above a healthy leaf node or bud to encourage new growth.
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Hard Pruning (if necessary): If the plant has become overgrown, cut it back harder to rejuvenate it.
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For specific types like Shasta Viburnum, focus on removing dead or crossing branches while preserving the horizontal structure.
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Special Types:
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Doublefile Viburnum: Remove vertical suckers and water sprouts to preserve its tiered structure.
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Cane-Growing Viburnums: Remove the oldest stems at ground level and maintain random, natural pruning patterns.
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By understanding the basics of viburnum pruning, you can keep your plants looking beautiful and healthy year after year.
Where is the best place to plant a viburnum?
Viburnums thrive in full sun but can also grow well in light to partial shade. They prefer moderately fertile, moist, well-drained soil with a pH level between 5.6 to 6.6. For optimal growth, ensure the site has good air circulation to prevent fungal diseases. Most viburnums will perform well with these conditions, offering vibrant blooms year-round.
