Many homeowners appreciate boxwoods for their ease of growth, but these plants are not entirely foolproof.
Boxwoods are popular for their thick, and luxurious hedges, but they are plagued with some issues that cause yellowing.
They are perfect as houseplants, and they can grow as formal hedges to form an entrance to your garden.
Some of the problems affecting boxwood are cured easily, while others can be very destructive.
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Why Are My Boxwoods Turning Yellow?
If boxwoods start turning yellow or brown, the most common reasons are rotting in the roots, severe nematode infestation, winter damage, aging, insect infestation, and lack of enough irrigation.
Understanding the Reasons Why Boxwoods May Turn Yellow
When the roots of boxwood shrubs are infected with fungal pathogens, there is root rot.
Root rot is a result of fungal infections, and it causes foliage loss, bark separation, and if left unmanaged, severe root rot causes poor plant growth. This manifests by turning green leaves yellow or brown and curling them upward and inward.
Like all plants, boxwoods have a hard time struggling when their roots are damaged. Rotting roots aren’t capable of absorbing soil nutrients.
To treat root rot in boxwood plants, minimize the watering rate for potted plants to promote drainage in the root region.
Nematodes are tiny roundworms that are very prevalent in boxwoods. They are microscopic pests that live off plants’ roots, leading to a decline in plant health.
Nematodes cause yellowing of plants and eventual plant death in the event of severe root damage.
If your plants are affected by nematodes, you can help lengthen their life by constant feeding and regular watering, but that isn’t a guarantee that they won’t die.
Boxwood can also turn yellow due to excessive cold, ice, snow, or winter burn, especially if you live in places with extreme temperatures during winter.
It takes a while to notice the yellowing because the cold-nipped tissues become obvious during spring.
If you notice the yellowing of boxwood early spring, you can help them recover by feeding and watering the bushes.
Yellow leaves in boxwood plants sometimes are caused by the aging process, so it might not be necessarily a symptom of anything.
This change might be unnoticeable for a while because boxwoods have a rather slow growth rate, but after a few years, the yellow leaves drop to accommodate new ones.
Yellowing Due to Drought and Insect Infestation
Yellowing of boxwood is a common problem during summer, especially when grown outdoors.
In some cases, the yellowing of boxwood leaves is caused by boxwood blight, but in other cases, there might be other reasons behind the yellowing of your boxwood plants.
Boxwood plants yellow due to the following reasons:
Boxwood plants require proper and adequate irrigation from time to time, otherwise, the leaves start turning yellow and brown.
When these plants lack rainfall for extended periods, they experience drought stress. That mostly affects the newly planted shrubs.
Some insects like boxwood mites, leaf miners, and boxwood psyllid are destructive and a threat to boxwood hedges, with leaf miners being the most common threat.
These insect problems cause browning and yellowing of leaves and eventual leaf drop from boxwood plants.
These insects feed on boxwood leaves making the plant have an unhealthy, and stunted growth with a yellow-leaved appearance.
These problematic pests swarm the plant and infest the leaves, causing them to have yellow or brown misshapen and swollen spots dropping from the plant.
If there is a severe infestation, the plant is defoliated and it eventually kills the plant.
Treating Yellowing Of Boxwood Plants
If you have a large infestation, and an option for biological control, use horticultural oils or insecticidal soap sprays to manage the situation.
Yellow boxwood can also turn back to green with time when given a chance for the leaves to fall out. Falling off of leaves allows new growth, which is shown by green boxwood leaves.
If you want to treat your yellow boxwoods, spray them during early spring before any new growth begins. Use a copper fungicide and follow the directions on the package till the new growth hardens enough.
If there is extra growth during late summer or fall, you need to spray again, especially if it is raining. You can also trim the plants by 1/3 to minimize interior humidity.
That also helps to rid of the affected parts, which cause fungal infestation. Ensure you remove all the dead growth before spraying.
What Causes Rotting of Roots in Boxwood Plants
Boxwood plants are predisposed to rot, especially in places with high temperatures where the soil moisture is retained for extended periods.
The condition is regulated by choosing viable locations with good drainage to plant boxwoods and regulating their irrigation properly.
If these plants stay wet for long, their roots may rot, which can be fatal depending on the extent of the damage.
They should only be watered when the soil begins drying out to avoid causing irreversible damage to the plant.
It’s also common for some plants to be affected while others stay healthy, especially when there is inadequate drainage in raised beds with rapid drainage.
Frequently Asked Questions about Why Boxwoods Turn Yellow
Can yellow boxwood turn green again?
Boxwood can turn from yellow to green, depending on the cause. If as a result of winter damage, relocate the plants to a place with partial shade. Use physical barriers to minimize wind velocity and manage winter wind damage if there are any. Yellow boxwood leaves caused by pest and insect infestation can be corrected by shaking the plants to get rid of flying leaf miners.
Why is boxwood popular?
For many homeowners and landscapers, boxwood is a preferred choice for hedgy plants and attractive shrubs. These topiary, classic hedge plants react well when shaped. They are most attractive when green, and if given proper care.
How do rotting roots cause yellowing in boxwood plants?
When the soil is overly wet, there is likely to be fungi due to poor drainage and soil infertility. Plants that are strong and healthy don’t get sick often. Due to regular water flow in drought seasons, the water stress causes leaves to turn yellow.
Boxwoods are popular decorative plants that appeal to many landscapers and homeowners for garden design to get that modern-day suburbia look.
These elegant plants need care and pruning to keep them healthy as they grow, and to make them less prone to fungus infestation, blight, and other fatal conditions.
Daniel has been a plant enthusiast for over 20 years. He owns hundreds of houseplants and prepares for the chili growing seasons yearly with great anticipation. His favorite plants are plant species in the Araceae family, such as Monstera, Philodendron, and Anthurium. He also loves gardening and is growing hot peppers, tomatoes, and many more vegetables.