5 Reasons Boxwoods Turn Yellow and How to Fix It

There can be several reasons for boxwoods turning yellow. Yellowing leaves do not necessarily signal that your shrub is dead. But they are concerning because they mar the appearance, at least temporarily, of a plant valued for the beauty of its delicate, leathery, rich green foliage.

Boxwoods are great shrubs for hedges, but the appearance of an entire hedge can be spoiled by the presence of yellow leaves on just one or two of the plants. The good news is that there is usually a way to fix the problem of boxwood turning yellow.

Learn some of the reasons boxwoods turn yellow and how to fix it.

5 Reasons Why Your Boxwoods Are Turning Yellow

There are many possible reasons for boxwood shrubs turning yellow. The fix is different for each, so it’s important to detect the reason in your particular case:

Fungal Diseases

Root rot and boxwood blight are fungal diseases that attack boxwood. Root rot is caused by fungal pathogens in the soil. As with all fungal problems, it is most prevalent where the soil is overly wet.

To avoid having your boxwoods turn yellow due to root rot (or to keep the problem from getting any worse), make sure:

• You don’t overwater
• The soil drains well

Boxwoods often harbor boxwood blight when they are being grown at the nursery. When you bring your plants home, you can accidentally spread them by shearing your shrubs in wet weather. This transports the disease from plant to plant.

Buy your plants only from reputable dealers. And when you shear boxwoods, frequently disinfect your shearing tools with a disinfectant such as bleach to prevent spreading the disease. Shear them only on dry days.

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Winter Damage

In the North, boxwood leaves may turn a coppery or yellowish color during the winter. This is caused by exposure to wind and sun, which dry the plant out at a time when, due to the frozen ground, water is not readily available to it.

To prevent this “winter burn,” spray an anti-desiccant on your boxwood in late November and again in late January. Alternatively, wrap your boxwood in burlap.

Salt Damage

If your boxwoods are planted along the road, they could suffer salt damage during the winter in the North. You’ll notice yellowing leaves come spring. When the salt gets on the leaves, it can dry them out. The salt can also get into the soil, keeping your shrubs from absorbing water properly.

Covering your plants isn’t sufficient in this case, since you wouldn’t be able to keep the salt from getting into the soil.

The only fix here is to choose a different planting location for your boxwoods. Alternatively, grow salt-tolerant plants along the road.

Dog Urine

Another cause of boxwoods turning yellow is stray dogs urinating on them. This happens because urine contains excessively high concentrations of nitrogen.

Use repellents to keep stray dogs out of your yard.

Pests

Boxwoods are attacked by pests such as leaf miners and scale. Serious infestations can result in boxwoods turning yellow.

Faithfully inspect your plants for pests, particularly the undersides of the leaves. If you find any pest activity, spray with insecticides such as Neem oil.

4 Tips to Grow Healthy Boxwoods

Despite all the various factors that can cause your boxwood’s leaves to turn yellow, boxwood is not an especially hard plant to grow. Nor is it high-maintenance unless you will be trimming it in a hedge. Here are a few tips to follow to keep your boxwoods healthy:

• Boxwoods are best planted in full sun in the North, partial shade in the South.
• Give your shrub a loamy soil that drains well.
• Locate it where it will be sheltered from winds.
• Boxwood roots are shallow, which can expose them to excessive heat. Put a layer of organic garden mulch, 3 inches thick, around your plant to give it protection from the heat.