Viburnum: How to Grow and Care with Success

Why Should I Grow Viburnum?

The genus Viburnum includes a wide range of deciduous or evergreen shrubs, which are often cultivated for ornamental purposes, but they also have other uses. Here are some factors that make viburnums special:

Ornamental Value

• Flowers: Different species produce showy flower clusters, ranging from white to pink and often fragrant. These are usually highly attractive to pollinators.
• Foliage: The viburnum leaves are often glossy and vibrant, adding aesthetic value. Some species have foliage that changes color in the fall.
• Berries: Many viburnum species produce berries that are visually appealing and are also attractive to birds. The color of the berries can range from red to black.

Ecological Value

• Wildlife Habitat: Viburnum shrubs provide shelter and food for various species of wildlife, including birds and insects.
• Pollinator-Friendly: The flowers are generally good for pollinators, providing nectar and pollen.

Versatility

• Landscape Use: Viburnums are commonly used in various landscaping applications including hedges, screening, or as specimen plants.
• Soil Tolerance: They can adapt to a wide range of soil types and pH levels, although they usually prefer well-drained soil.
• Climate Range: Different species are suited to different climates, from temperate to subtropical.

Culinary Uses

• Edible Parts: Some viburnum species produce berries that are edible, although not all are palatable. They can be used in jellies, jams, or even wines.

When to Plant Viburnum

• Spring or Fall: These seasons are generally the best times to plant viburnum. Spring planting should happen after the last frost, while fall planting should be completed several weeks before the first hard frost.
• Avoid Extreme Conditions: Try not to plant during periods of extreme heat or cold, as this can stress the plant and hinder successful establishment.

Where to Plant Viburnum

• Sunlight: Most viburnum species prefer full sun to partial shade. However, some species can tolerate full shade. Consult the specific requirements for the species you are planting.
• Soil: Viburnums are quite adaptable to different soil types but prefer well-drained soil rich in organic matter. Some species have specific pH requirements.
• Spacing: Ensure adequate space between plants to accommodate their mature size. This could range from 3 to 15 feet (0.9 to 4.5 meters), depending on the species and the desired function (e.g., hedge, specimen plant).
• Site Selection: Choose a location where the plant can serve its intended purpose. For example, some species make excellent hedges or privacy screens, while others are better as ornamental focal points.

How to Plant Viburnum

• Dig a Hole: The planting hole should be about twice the width and the same depth as the root ball of your viburnum plant.
• Soil Preparation: Amend the excavated soil with compost or other organic matter, especially if the soil is poor. This will improve drainage and fertility.
• Planting: Remove the viburnum from its container or burlap wrap, taking care not to damage the root system. Place it in the hole so that the top of the root ball is level with the soil surface.
• Backfill: Fill the hole with the amended soil, tamping down as you go to remove air pockets. Make a small mound or basin around the plant to help direct water to the roots.
• Watering: Water the plant thoroughly immediately after planting to help the soil settle. Keep the soil consistently moist (but not waterlogged) for the first year to help the plant establish its root system.
• Mulching: Apply a 2-3 inch (5-7 cm) layer of mulch around the base of the plant, but keep the mulch away from the stem to prevent rot.
• Staking: Some taller or top-heavy specimens may require staking to keep them upright until they are established.
• Follow-up Care: Monitor the plant for signs of stress, such as wilting or leaf drop, and adjust your care regimen as needed.

How to Care for Viburnum

Caring for viburnum generally involves a combination of proper planting, regular watering, periodic fertilizing, and occasional pruning. The level of care may vary depending on the specific species of viburnum you’re dealing with, but the following guidelines generally apply to most:

Watering

• Initial Care: Keep the soil consistently moist during the first growing season to help establish the root system.
• Ongoing Care: Once established, viburnums are relatively drought-tolerant but will do best with regular watering, especially in dry periods. Overwatering or poor drainage should be avoided.

Fertilizing

• General Nutrient Needs: A balanced, slow-release fertilizer applied in early spring is generally sufficient for viburnum.
• Soil Testing: For specific nutrient needs, it may be beneficial to perform a soil test and amend the soil accordingly.

Pruning

• Timing: For species that flower on old wood, prune immediately after flowering to shape the plant and remove any dead or damaged branches. For those that flower on new wood, late winter or early spring pruning is generally suitable.
• Technique: Use clean, sharp pruning shears to make clean cuts. Remove any diseased or damaged branches first, then shape as desired.

Mulching

• Purpose: Mulch helps retain soil moisture, suppress weeds, and improve soil quality.
• Application: Apply a 2-3 inch (5-7 cm) layer of organic mulch around the base of the plant, avoiding direct contact with the stem.

How to Propagate

Propagating viburnum can be done in various ways, depending on what is most convenient for you and the specific species of viburnum you’re working with. Here are some of the most common methods:

Seeds

• Collecting: Collect seeds from ripe viburnum fruit in late summer to early autumn.
• Stratification: Many viburnum seeds require a period of cold stratification to break dormancy. This involves storing the seeds in moistened peat moss or sand in a sealed bag in the refrigerator for a specific period, often several months.
• Planting: Sow stratified seeds in pots filled with a seed-starting mix. Place the pots in a warm location and keep the soil moist.

Cuttings

• Timing: The best time to take cuttings is generally in late spring to early summer, although it can also be done in early autumn for some species.
• Cutting Technique: Use a sharp, sterilized knife to cut a 4- to 6-inch (10-15 cm) length of new growth. The cutting should have at least two sets of leaves at the top.
• Preparation: Remove the leaves from the lower half of the cutting and dip the cut end into rooting hormone powder.
• Planting: Plant the cuttings in pots filled with a mix of peat moss and perlite or a rooting medium. Keep the medium moist but not waterlogged.
• Environment: Place the cuttings in a humid environment, such as inside a plastic bag or under a plastic dome. Some gardeners use a heat mat set to a low temperature to encourage root growth.

Layering

• Timing: This is best done in late winter to early spring, depending on the climate.
• Technique: Bend a low-growing branch down to the soil level. Make a small cut or nick on the branch where it will contact the soil. This will encourage rooting at that point.
• Securing and Covering: Secure the branch in place with a piece of wire or a rock, and cover the nicked section with soil.
• Rooting: After several months, the branch should develop roots at the point of contact with the soil. Once you confirm root development, you can sever the new plant from the parent and transplant it.

Division

• Timing: Early spring or late autumn is usually the best time for division.
• Technique: Dig up a healthy, well-established viburnum that has multiple stems. Carefully divide the root ball into sections using a sharp, sterilized spade or knife. Each section should have a good amount of roots and at least one stem.
• Planting: Replant the divisions immediately, water well, and provide care as you would for a newly planted viburnum.

Each of these methods has its own set of benefits and challenges, so you might want to try more than one to see which works best for you. Always consult resources specific to the species of viburnum you are propagating for the best results.

Garden Design with Viburnum

Viburnum can be an excellent choice for various garden styles and functions due to its versatility, attractive features, and relatively easy care. Here are some ideas on how to incorporate viburnum into your garden design:

Focal Point

• Specimen Plants: Larger, more ornate species can serve as specimen plants. Their showy flowers, attractive leaves, and colorful berries can draw attention and serve as a visual centerpiece.

Borders and Edges

• Hedge or Screen: Viburnums can create a living fence or screen, providing privacy and dividing spaces. Some species have dense growth habits suitable for this purpose.
• Mixed Border: Combine viburnums with other shrubs, perennials, and annuals to create a layered look. Viburnums can provide the mid-level layer, between taller trees and shorter ground covers.

Woodland and Naturalistic Gardens

• Understory Planting: Some viburnum species are well-suited for partial to full shade and can be used as understory plants in woodland or naturalistic gardens.
• Wildlife Habitat: The berries of many viburnum species attract birds, making them a good choice for a wildlife or bird garden.

Themed Gardens

• Fragrant Garden: If you’re interested in fragrant plants, choose viburnum species known for their scented flowers, like Viburnum carlesii or Viburnum x juddii.
• Four-Season Interest: Select species that offer multiple seasons of interest, such as spring flowers, summer berries, and colorful autumn foliage.

Companion Plants

Selecting the right companion plants can enhance the beauty of your viburnum and create a well-balanced and thriving garden. Here are some ideas for plants that generally pair well with viburnum:

Perennials

• Hostas: Their broad leaves provide a nice textural contrast to viburnum foliage and they’re often tolerant of the same conditions, particularly shade.
• Astilbe: Astilbe’s feathery flower spikes provide a nice contrast to the generally more solid, rounded clusters of viburnum flowers.
• Bleeding Heart (Dicentra): The unique, arching sprays of heart-shaped flowers can add an entirely different texture and form to the garden, contrasting well with viburnum.
• Columbine (Aquilegia): The intricate, nodding flowers of columbine add a delicate touch that can offset the more robust form of viburnum.
• Asters: These late-blooming perennials can pick up where your viburnum flowers leave off, offering late-season blooms.
• Ferns: For woodland or shade gardens, ferns can provide a beautiful textural contrast with viburnum and can thrive in similar shady conditions.

Shrubs

• Rhododendron/Azalea: The evergreen foliage and vibrant spring blooms complement many types of viburnum, and they often have similar acidic soil requirements.
• Hydrangea: The large flower heads of hydrangeas can make a striking contrast to the smaller clusters of viburnum flowers, while the foliage complements each other well.
• Boxwood: This evergreen shrub can serve as a low-growing hedge in front of taller viburnum varieties, offering year-round interest.

Trees

• Japanese Maples (Acer palmatum): The finely cut leaves and often dramatic fall color of Japanese maples can make a striking contrast to the more substantial leaves and softer autumn hues of viburnum.
• Birch: The light bark and delicate leaves can provide a nice contrast to the more robust viburnum.
• Dogwoods (Cornus): The springtime blooms (often appearing as bracts) and colorful stems of some dogwood varieties can provide multi-season interest that complements viburnum well.
• Redbud (Cercis): This small to medium-sized deciduous tree is prized for its striking early-spring blooms of pink to lavender flowers. It’s a versatile tree that can complement a viburnum in many ways: floral interest, foliage, and fall color.

Bulbs

• Daffodils, Crocus, and Tulips: Early-spring flowering bulbs can offer color before your viburnum blooms, filling in seasonal gaps in your garden’s flowering schedule.

Pests and Diseases

Viburnum shrubs are generally hardy and relatively easy to grow, but like many plants, they can be susceptible to certain pests and diseases. Below are some of the most common problems that can afflict viburnum:

Pests

• Aphids: These small, sap-sucking insects can be found on the undersides of leaves. They can cause leaf distortion and can also produce honeydew, which leads to sooty mold. Control measures include insecticidal soaps or neem oil.
• Scale: These are small, flat insects that attach themselves to stems and leaves. They suck the plant’s sap and can weaken it over time. Horticultural oils can be effective in controlling scale.
• Spider Mites: These tiny arachnids can cause stippling and discoloration of leaves. Miticides or insecticidal soaps can be used for control, but it’s also important to maintain good watering practices to reduce plant stress.
• Thrips: Thrips are tiny insects that can cause discoloration and stippling on leaves. In severe infestations, leaves may become distorted. Insecticidal soaps or pyrethroid-based insecticides can be effective.
• Viburnum Leaf Beetle: This is a more specific pest that can defoliate viburnum plants. Infested leaves have a lace-like appearance. Control may involve pruning and destroying infested twigs and using insecticides as a last resort.

Diseases

• Powdery Mildew: This disease appears as a white, powdery substance on leaves and can lead to leaf distortion. It usually occurs in humid conditions. Fungicides and good air circulation can help manage this disease.
• Algal Leaf Spot: Appears as green, orange, or reddish-brown spots on the leaves. Generally, it is more of an aesthetic issue than a serious health problem for the plant. Reducing leaf wetness through proper spacing and watering can help. If the problem is severe, copper-based fungicides can be used according to the manufacturer’s guidelines.
• Leaf Spot Diseases: Various fungi can cause spots on viburnum leaves. While usually not fatal, severe infections can weaken the plant. Remove and destroy affected leaves and consider fungicidal treatment.
• Downy Mildew: This appears as yellow patches on the upper leaf surface and purplish mold on the underside. Like powdery mildew, it is more common in humid conditions. Fungicides can be used for control.
• Botryosphaeria Canker and Dieback: This fungal disease results in cankers or lesions on the stems and dieback of shoots. Prune out and dispose of infected branches. Improving air circulation and reducing plant stress through proper watering and fertilization can also help manage this disease.
• Crown Gall: Crown gall manifests as tumor-like growths on the roots and sometimes at the base of the stem. The galls can interfere with the plant’s ability to take up water and nutrients. There is no effective chemical control for crown gall. Infected plants should be removed and destroyed to prevent the spread of the bacterium to other plants.
• Root Rot: Usually caused by overly wet soil conditions, symptoms include wilting and yellowing leaves. This can often be avoided by ensuring good soil drainage.

Preventative Measures

• Proper Spacing: Make sure plants are spaced adequately for good air circulation, which can reduce the occurrence of fungal diseases.
• Cleanliness: Keep the area around the shrubs free of fallen leaves and debris, which can harbor pests and diseases.
• Watering: Water at the base of the plant rather than overhead to reduce the likelihood of fungal diseases.
• Regular Monitoring: Regularly check for signs of pests and diseases so you can catch problems early, when they are easier to manage.
• Cultural Practices: Use mulch to retain soil moisture and suppress weeds, but avoid piling it against the stem, which can promote rot.