Why Is Your Green Velvet Boxwood Turning Brown?

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Shrubs really lose their appeal when they start turning brown. So what causes browning in green velvet boxwood?

Your green velvet boxwood can turn brown due to wrong soil conditions, excessive sunlight, and boxwood blight. Your boxwood can become lush green and healthy again under the right conditions. 

This article will explain these factors in greater detail and provide practical solutions. 

1. Wrong Soil Conditions

Green velvet boxwood thrives in specific soil conditions. Any deviation will affect the growth of the plant and cause browning. 

The soil conditions that can affect your velvet boxwood plant include:

• Soil pH
• Soil salinity
• Moisture
• Soil type

Soil pH

Green velvet boxwood thrives in a slightly acidic to slightly alkaline soil with a pH range of 5.5 – 7.5. If your plant isn’t doing well, test the pH of the soil. You can purchase a soil test kit online (link to Amazon).

You can increase or lower soil pH depending on your goal. To increase soil acidity, try adding iron sulfate, ammonium sulfate, or acidic fertilizers.

On the other hand, you can reduce soil pH by adding wood ash, baking soda, or lime-containing materials like garden lime, quicklime, or dolomite lime.

However, if your tests confirm that your soil pH is within the recommended range, you should proceed to check other soil parameters.

Soil Salinity

A high salt concentration in the soil is detrimental to your green velvet boxwood (source). Salt in the soil will draw water from plant roots back into the soil, leading to dehydration.

But how do you establish the salt level in your soil is high? 

Take your soil samples to a laboratory for a soil salinity test. You can also perform the test yourself by following the steps in this YouTube video:

Saline agriculture - Training video: How to take a soil sample and measure soil salinity

To reduce soil salinity, try adding organic fertilizers. Other methods include leaching and mulching. While leaching involves adding water to the soil to dissolve the salts, mulching involves blocking spaces to prevent erosion and water loss.

Moisture

Excess moisture isn’t healthy for your green velvet boxwood. It can lead to many problems, such as root rot, loss of nutrients, and stunted growth. Any of these conditions can cause browning in green velvet boxwood.

Too much moisture is a result of poor drainage (source). You can improve the drainage around your plants by creating a drainage system to redirect water flow. If installing such a system is expensive, consider planting your green velvet boxwood in an area with proper drainage.

Soil Type

Green velvet boxwood can thrive in any soil, provided it’s properly aerated and well drained. This reduces a gardener’s headache in choosing suitable soil for green velvet boxwood.

If your soil drains well, you can plant your velvet boxwood and expect them to grow well with proper care.

2. Excessive Sunlight 

Excessive sunlight can contribute to browning in green velvet boxwood. True, your plant needs sunlight to grow well, but it also needs some amount of shade. 

Getting the right sun and shade balance is important for your green velvet boxwood. Plant trees around your shrub to limit sunlight exposure and provide the plant’s required shade.

See our guide to 19 Shade-Tolerant or Shade-Loving Evergreens.

One major effect of excessive sunlight in green velvet boxwood is drought stress. This occurs when environmental conditions, such as excessive sunlight, cause a depletion in soil water.

Drought stress can manifest in several ways: 

• Browning 
• yellowing
• Reduction in leaf size
• Brittleness, 
• Leaf limpness
• Senescence (source).

3. Boxwood Blight

Disease can also cause browning in green velvet boxwood. The most common disease that affects this shrub is the boxwood blight, a fungal disease caused by Calonectria pseudonaviculata (source). Boxwood blight causes loss of leaves and even death in boxwood plants. 

But how do you know your green velvet boxwood has Boxwood blight? Some signs of the disease include:

• Rapid leaf loss
• Stem lesions
• Blotches on the leaf

The disease first appears as dark spots on leaves and stems. Then, the plant begins to shed leaves very quickly. The plant can die a few days after losing all its leaves.

Treatment for Boxwood Blight

There is no treatment for Boxwood blight, but there are a few things you can do if your plant has this disease, depending on the stage of infection.

• Cut off affected branches. This option is still viable at the early stage of infection.
• Sanitize all cleaning tools. Since you’ll be using the tools again, you should ensure they’re clear from infection. Use bleach (1:9) for effective results. 
• Properly dispose of the diseased part. Don’t compost the parts you have removed. It’s best to burn them. If you want to bury them, do so at a considerable distance away from your plant. Also, bury them deep enough. The recommended minimum depth should be 2 feet (60.96 cm).
• Spray fungicide on the unaffected parts periodically (weekly or fortnightly) during the growing season. Boxwood planting seasons are usually warm and rainy – favorable conditions for fungus growth. Chlorothalonil is the most effective option. You can also mix chlorothalonil with thiophanate methyl.

How To Prevent Boxwood Blight

Cutting off affected plant parts won’t help the situation if the disease is advanced. So prevention remains your best bet to keep your plants healthy and safe.

Here’s how to prevent your green velvet boxwood from contracting boxwood blight.

• Ensure you plant only fungal-free boxwoods. For assurance, buy boxwood for planting only from disease-free certified nurseries.
• Plant cultivars far apart from each other to increase airflow. Sufficient air dries up moisture and discourages the growth of blight spores.
• Don’t prune or weed the plants when they’re wet. Doing this can increase the spread of blight spores from plant to plant.
• Always sanitize your tools before using them on another plant. This measure will curb possible transmission between plants.

Final Thoughts

A healthy and mature green velvet boxwood gives beauty and splendor to your garden. However, your boxwood loses appeal when they turn brown – a condition that may be due to the following factors:

• Wrong soil conditions (salinity, pH, moisture, and soil type)
• Excessive sunlight 
• Disease

Providing the appropriate conditions will help restore the plant to its original health and beauty.

Recommended Reading:

• Are Green Velvet Boxwoods Deer Resistant?