Shrub · Adoxaceae
Viburnum
Viburnum
Given sun, space, and steady water while young, viburnum shows off white or pink spring clusters and deep fall berries for decades.
Full sun
Every 5–10 days
USDA 2–8
4–12 ft · 1.2–3.7 m
Overview
Viburnum is a deciduous shrub whose branches carry two very different displays. In spring the stems hold rounded clusters of small white or pink flowers, many of them releasing a sweet scent up close. By fall the same plant hangs with bright, colorful berries and leaves that flush into burning color. Across the genus the frame ranges from a low rounded mound to a woody shape near the size of a small tree.
Handled in the garden, it proves as tough as it looks unfussy. The wood is hardy to -40°F (-40°C), the shrub holds up in full sun or part shade, and the roots take to clay, loam, or sand. Once those roots run deep, most kinds carry on through a dry spell on their own.
The fall berries are the shrub's most vivid feature, ripening in clusters that songbirds pick over through the season. The dense tangle of branches gives cover for nesting, so the plant is as busy as it is colorful. Set close to a path, its spring clusters put both color and fragrance within arm's reach.
Care
The short version: grow viburnum in full sun to part shade in average, well-drained soil, keep it watered while it settles in, and prune right after the spring flowers fade.
Light
In full sun viburnum sets the most flowers and the heaviest crop of berries, though it will still grow under partial sun or partial shade. Sink it into deep shade and both the pale spring clusters and the fall fruit thin out.
Water
Viburnum likes its soil evenly moist and well-drained, above all while the young roots spread. Water deeply through the first season and any dry stretch, every 5 to 10 days as the ground dries. Once settled, most viburnums stand up to drought on their own.
Soil
Average, medium-moisture loam sits well beneath viburnum, and its roots also grip clay or sand. Aim for a slightly acidic to neutral pH of 5.5 to 7.0, and let water drain away so it never stands around the crown.
Temperature
The wood is cold-hardy down to -40°F (-40°C) and holds through summer heat up to 95°F (35°C). That span reaches across most temperate gardens, so the shrub rarely needs shielding from the cold.
Humidity
Plain outdoor air suits it, so there is no level to hit. What counts is the air moving through the branches, since still, damp air on crowded leaves brings on the powdery film of mildew and dark leaf spot.
Feeding
A balanced slow-release or general shrub fertilizer in early spring is all it takes. Set in decent soil, a viburnum often needs little to no feeding, so a light hand serves it best.
Pruning
Cut right after the flowers drop, since next spring's buds are already set on the old wood and a late cut takes them off. Clear out any dead, damaged, or crossing stems and shape the frame as you go. An old, overgrown plant will even take a hard cut back to bare wood and regrow.
Repotting
As a landscape shrub, viburnum rarely needs repotting. A potted one wants a larger container only when the roots coil inside it, push out the drainage holes, or send water straight through.
Size & spacing
At maturity the shrub stands 4 to 12 feet (1.2 to 3.7 m) tall and spreads 4 to 10 foot (1.2 to 3 m) wide, depending on the kind. Give it the full width so air slips between the branches and disease finds no foothold.
When to plant
Viburnum forms its flower buds on old wood, so pruning, not planting, sets the calendar. New shrubs go into mild spring or fall ground, the clustered flowers open from March into May, and the berries deepen in color from late summer into fall.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Spring or fall
- Harvest: Spring (March to May); colorful berries ripen late summer into fall
Hardiness
USDA hardiness zones: 2–8
Temperature: down to -46°C
Troubleshooting
Most of what goes wrong with viburnum is written on the leaves, from chewed foliage to a powdery film or dark spotting. Spotted early, the shrub grows back clean. Match the look below, then act before it spreads.
Leaves reduced to a lacework of veins in spring
When spring foliage thins to a skeleton of veins, the viburnum leaf beetle is feeding, its small greenish-yellow larvae and later the adults eating everything but the ribs. Three hard years running can leave the branches bare and finish the shrub, so act early. Cut out and burn the twigs carrying the egg rows over winter, then treat the young larvae soon after they hatch in spring.
Fix:
- Prune out and destroy egg-infested twigs between October and April before larvae hatch
- Treat newly hatched larvae in spring with a labeled insecticide applied shortly after emergence
- Alternatively apply a single labeled systemic soil drench in spring but no later than early July to control adults
Sharp-edged dark spots marking the leaves
Dark blotches with hard, angular edges that widen in cool, wet spring weather are bacterial leaf spot, and a stressed shrub may also lose shoots to a crown borer. The straight, angled margins tell it apart from the rounder blots a fungus makes. Pick off and destroy the marked leaves, prune out the worst shoots, and keep water off the foliage so the surface dries fast.
Fix:
- Remove and destroy infected leaves and prune out badly affected shoots
- Avoid overhead watering and work plants only when dry
- Improve spacing and airflow to speed leaf drying
A pale powdery film over the top of the leaves
The white-to-gray dust across the upper leaf surface is powdery mildew, a fungus that spreads on crowded, shaded plants when the days are warm and the nights cool. The coating looks alarming but seldom leaves lasting damage. Thin the shrub with selective pruning to open it to light, and reach for a labeled fungicide only if the film keeps spreading. Keep sulfur off, since it scorches sulfur-sensitive viburnums.
Fix:
- Improve air circulation by proper spacing and selective pruning
- Reduce excessive shade
- Apply a labeled fungicide such as myclobutanil, propiconazole, or thiophanate-methyl if needed; use horticultural oil only when temperatures stay below 85 degrees F
- Do not use sulfur, which can injure sulfur-sensitive viburnums
Toxicity
Viburnum is a safe shrub to grow within reach of pets. The ASPCA lists it as non-toxic to cats, dogs, and horses, and its bright berries feed birds rather than harm them. A pet that chews a mouthful of leaves may have a brief stomach upset, but nothing in the plant is truly poisonous.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Viburnum is safe for cats. A cat that works through a mouthful of leaves may drool or bring the greenery back up, the ordinary reaction to plant material rather than poisoning.
Dogs None
Dogs are unharmed by viburnum. A dog that bolts a heap of foliage or berries may feel a short stomach upset, but no toxin lurks in the leaves or fruit.
Horses None
The shrub is non-toxic to horses, so a browse along the hedge leaves them fine.
Rabbits Safe
Rabbits can crop viburnum safely, since nothing harmful sits in the leaves or twigs, though a diet built on any single plant is never ideal.
Livestock Safe
Cattle, goats, and sheep can browse the foliage without harm, since none of it is poisonous to grazing animals.
Birds Safe
Birds crowd the ripe berries and strip them fast. That fruit feeds songbirds through fall and is one of the shrub's real garden strengths.
People Safe
Viburnum is not dangerous to people. Eating a lot of raw fruit from some species can bring on a mild stomach upset, but it is not seriously toxic.
Although not toxic, eating any plant material can cause mild, temporary stomach upset or vomiting in pets, and large quantities of raw fruit of some species may cause mild digestive upset in people.
Varieties
The genus runs to hundreds of species and cultivars, each with its own look. A few stand out for their scent, their fruit color, or their sheer toughness, and these reward a closer look.
Viburnum carlesii (Koreanspice viburnum)
A slow-growing shrub of 4 to 6 foot whose pink buds swell and open into fragrant, rounded white snowball clusters in early spring, then darken to blue-black berries by fall.
Viburnum dentatum (Arrowwood)
A tough native reaching 5 to 10 feet, carrying flat, creamy-white flower heads, blue-black drupes that draw the birds, and dependable deer resistance.
Viburnum lentago (Nannyberry / Black Haw)
A tall native viburnum that the ASPCA confirms is non-toxic to cats, dogs, and horses.
Viburnum opulus (European cranberrybush)
A non-native strung with showy red fruit that has turned invasive in parts of the US, unlike the well-behaved native viburnums.
How to propagate
Viburnum can be increased three ways, from quick softwood cuttings to slow seed, each with its own pace from cut stem to rooted plant.
Stem cuttingsModerate
Late spring to early summer while growth is soft (softwood) · Roots in about 3-4 weeks under mist; transplantable plants in about 3 months
Softwood cuttings copy a named cultivar true to type. Take them in late spring to early summer while the new growth still bends soft, dip the cut end in rooting hormone, and hold them warm and humid. Roots break in about 3 to 4 weeks under mist, and the young plants are ready to move on in roughly 3 months.
SeedDemanding
Sow fresh seed in fall outdoors · Often 1-2 years to germinate due to double dormancy
The straight species will grow from seed, but slowly. Sow fresh seed outdoors in fall, and a double dormancy can hold it in the ground for 1 to 2 years before the first shoots break, often uneven. Seed off a cultivar will not come true to the parent.
LayeringEasy
Spring to summer · Several months to a year to root
Layering is the simplest route when a shrub carries low, flexible branches. Pin one down into the soil in spring or summer, leave it joined to the parent while roots form over several months to a year, then cut it free as its own plant.
Myths
A single viburnum will hang heavy with berries on its own.
Most viburnums color up with fruit only when a second, genetically different cultivar of the same species stands nearby to pollinate them. Plant just one and the branches often carry few berries, or none at all.
Viburnum berries are dangerously poisonous.
The ASPCA lists viburnum as non-toxic to cats, dogs, and horses. Eating a good deal of the raw fruit of some species may leave a person with a mild stomach upset, but the plant is not seriously toxic.