A Guide to Identifying and Addressing Boxwood Problems

Spring conditions have brought about a number of issues on boxwoods, posing issues for homeowners throughout the mid-Atlantic.

Prized for their vibrant green color year-round, boxwoods are a landscape staple in our area. Because of their prevalence and importance to many landscapes, common problems on these woody shrubs can become a major eyesore.

Boxwood Psyllids

One of the pests that experts have been noticing on boxwoods in the last few weeks is boxwood psyllids. These tiny pests feed exclusively on boxwoods and can be identified by looking for “cupping” of the leaves or the waxy, white secretions they leave behind.

Although their presence may result in some minor aesthetic issues, the good news is that boxwood psyllids won’t typically harm the overall health of your boxwoods. They only have one generation per year and rarely do enough damage during their lifespans to warrant treatment.

We recommend not treating your boxwoods for these pests as the introduction of unnecessary pesticides can harm beneficial insects that naturally ward off predators.

Waxy, white boxwood psyllid secretions on a Green Velvet boxwood in Northern Virginia

Phytophthora Root Rot

This fungal disease often affects shrubs that are planted in areas with poorly draining soil.

The signs you should look out for:

  • Slower growth
  • Reduced vigor
  • Undersized leaves
  • Dieback of foliage
  • Drooping or curling leaves
  • Browning of foliage

Learn more about phytophthora root rot here.

Boxwood with a yellow patch caused by phytophthora root rot. Clay soil can be notoriously poor-draining, which can contribute to your boxwoods developing this fungal issue.

Boxwood Leafminer

These small insects resemble mosquitoes but are actually an invasive species which lays eggs inside boxwood leaf tissue.

At this point in the season, the leafminers have entered the adult stage and are no longer causing damage to your shrubs. However, in April or May (the larval and pupal stages), you may have noticed the tell-tale “bubbles” on the leaves.

Learn more about boxwood leafminer here.

Fun fact: if you pop the “bubbles” on the leaves during the larval stage, you can actually see the larvae inside!!

Boxwood Blight

Perhaps the most sinister of all boxwood problems, boxwood blight is a fungal disease that will eventually kill your boxwoods.

The signs you should look out for:

  • Defoliation  / leaf drop, especially if it starts at the bottom of the plant
  • Dark leaf spots
  • Black lesions / cankers on the green stems
  • Browning of the foliage

If your boxwoods have boxwood blight, it’s important to exercise caution. Because of the contagious nature of the disease, it’s important to disinfect tools, gloves, clothing, and hands that have come in contact with an infected boxwood to avoid spreading the disease.  

Click here for more information on boxwood blight.

Boxwood in Falls Church, VA with a severe case of boxwood blight.

How to Keep Your Boxwoods Healthy and Happy

  • Canopy Protection Program: For fungal issues on boxwoods, prevention is key. We highly recommend having a trained professional monitor your property regularly for signs of disease and pest issues. With this easy program, you’ll have an environmental specialist on your property at least (7) times per year to keep an eye on things. During these visits, your environmental specialist will treat all boxwoods preventatively for fungal issues, which is crucial since treating after infection is oftentimes futile.
  • Bio-Stimulants: For stressed or weakened trees and shrubs, we always recommend Bio-Stimulants. We typically suggest two applications per year to help plants recover from disease and insect damage. There are other benefits to Bio-Stimulants; check them out here!
  • Anti-desiccants: Boxwoods are susceptible to winter burn, which causes yellowing of the foliage due to moisture leaving the plant at a high rate. Winter burn causes extreme stress to your boxwoods, making them more susceptible to diseases and pests in the spring and summer. Anti-desiccant treatments can help to lock in the moisture and prevent winter burn. Learn more about anti-desiccants and helping winter-burned boxwoods here.

Need some help caring for your boxwoods?

Call us at 703.573.3029

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