How to Trim Arrowwood Viburnum Shrub: An In-Depth Pruning Guide

Arrowwood viburnum (Viburnum dentatum) is a popular deciduous shrub known for its white spring blooms, shiny leaves, and blue berries in late summer. Like most shrubs, arrowwood viburnum requires occasional pruning to maintain its shape, encourage new growth, and remove any damaged or diseased stems.

Proper pruning is key to keeping arrowwood viburnum attractive and vigorous. This in-depth guide will cover when to prune arrowwood viburnum, what tools to use, and step-by-step instructions for pruning this beautiful shrub.

When to Prune Arrowwood Viburnum

Arrowwood viburnum blooms on old wood, meaning the flower buds form on stems produced in the previous growing season. For that reason, the optimal time for pruning is soon after flowering in late spring or early summer.

Pruning at this time allows you to shape the shrub without removing potential flower buds for next year It also gives the shrub plenty of time to produce new growth before going dormant in winter

Avoid pruning in late summer or fall as this can stimulate tender new growth that may not have time to harden off before the first frost. Late winter pruning is also not ideal as you may accidentally remove flower buds.

Pruning Tools Needed

Having the right pruning tools makes the job easier and helps ensure clean cuts that heal quickly. For arrowwood viburnum all you need are

• Bypass hand pruners – For cutting smaller stems up to 1⁄2 inch thick
• Loppers – For thicker stems up to 11⁄2 inches diameter
• Pruning saw – For old, thick stems over 11⁄2 inches diameter
• Garden shears – For trimming additional growth if needed

Bypass pruners, loppers, and saws make cleaner cuts than anvil styles. Make sure your tools are sharp to reduce damage to the shrub. Disinfect tools with isopropyl alcohol before each use to avoid spreading disease between plants.

How to Prune Arrowwood Viburnum

Follow these simple steps for pruning arrowwood viburnum:

1. Remove Dead or Damaged Growth

The first priority is getting rid of any dead, diseased, or broken stems. This helps improve air circulation and allows the shrub to focus energy on healthy growth.

Make cuts just above healthy buds or leaves. For major dieback, cut back to just above the ground to encourage new shoots from the roots.

2. Thin Out Congested Stems

Over time, arrowwood viburnum can become overgrown and congested. Thinning helps light and air reach inner branches.

Select and remove any stems that rub or cross over each other. Also consider removing older stems that look woody and lack vigor. This stimulates new growth.

3. Shape and Contain Size

Arrowwood viburnum can reach 8-15 feet tall and wide at maturity. Pruning is necessary to keep growth contained.

Identify any wayward branches growing outside the desired shape. Make pruning cuts just above an outward facing bud or leaf to encourage growth in the intended direction.

Aim to reduce the shrub’s overall size by no more than one-third. Removing too much at once can leave unsightly holes and shock the plant. Go slowly over several years to gradually reduce size.

For formal hedges, trim to the desired shape after the main pruning. Make cuts on the top and sides just above a bud.

4. Clean Up Debris

As a final step, clear away all fallen stems and leaves around the shrub. Debris can harbor pests and diseases.

Properly dispose of diseased trimmings by burning or burying them. Healthy debris can be chopped and added to a compost pile.

Pruning Tips for Arrowwood Viburnum

Follow these tips to keep your arrowwood viburnum looking its best:

• Prune right after flowering, before summer heat triggers new growth
• Remove up to one-third of the shrub when reducing size
• Use sharp, clean tools to minimize injury to the plant
• Disinfect tools before use to prevent disease spread
• Thin out old, congested wood to improve air circulation
• Cut back damaged or diseased wood as needed throughout the year
• Shape formal hedges with a light trim after the main prune

With the proper annual pruning, arrowwood viburnum will continue providing year-round interest and structure to your landscape for years to come. Paying attention to when and how much you prune is key to maintaining its health and natural beauty.

Common Pruning Mistakes

It’s easy to damage arrowwood viburnum by pruning incorrectly. Avoid these common mistakes:

• Pruning in late summer or fall – Removing growth too late in the season can stimulate tender new shoots before winter. Wait to prune until after flowering.

• Overpruning – Cutting back more than one-third of the shrub at once can shock the plant. Take a gradual approach over several years to reshape overgrown plants.

• Skipping yearly pruning – Arrowwood viburnum needs annual pruning to control size and remove dead wood. Neglecting this can lead to dieback and disease.

• Using dull tools – Jagged cuts from dull blades leave wounds that are slow to heal. Use clean, sharp tools to prune.

• Improper cut placement – Always cut just above healthy buds or leaves facing the desired direction of new growth. Avoid leaving stubs.

• Failure to remove debris – Fallen leaves and stems trapped under the shrub can spread pests and disease. Promptly dispose of pruning debris when finished.

When to Call a Professional

You may need to call in a professional arborist or gardener for arrowwood viburnum pruning if:

• The shrub is extremely overgrown, needing major size reduction
• You need to remove large branches over 2 inches diameter
• The shrub is too tall or difficult to reach safely
• Disease is suspected and experts are needed for diagnosis
• You do not have the right pruning tools for the job

Hiring a professional can be money well spent to properly rejuvenate and reshape overgrown, unruly viburnum shrubs. They have the skills, tools, and experience to handle challenging pruning jobs.

Enjoying Arrowwood Viburnum Year-Round

Arrowwood viburnum is one of the most versatile landscape shrubs, but it does require a bit of annual maintenance to keep it looking its best. By properly thinning and shaping the shrub each spring after blooming, you can highlight its graceful form and seasonal beauty.

Here is what you can look forward to when arrowwood viburnum is happily growing in your garden:

Spring – Clusters of small white flowers line the branches in late spring, soon giving way to shiny green foliage. Prune immediately after flowering.

Summer – The leaves provide a nice green backdrop through summer. Blue berry-like fruits gradually develop, adding late summer interest.

Fall – The leaves turn shades of red and purple in autumn before dropping. The fruits can persist into early winter if not eaten by birds.

Winter – The bare branching structure adds winter interest. Flower buds will form on old wood for the coming spring bloom.

Taking time to properly prune and care for arrowwood viburnum will keep it healthy and looking its best year-round. Follow this guide for the when, how, and how much to prune arrowwood viburnum and you’ll enjoy this beautiful shrub for years to come.