Quote from Lee Garden Ninja on 2nd September 2024, 9:51 am

Hi @mumslittlegarden

Thanks for your question about the orange spots on your box or Buxus hedge. The good news is it isn't box blight, but it is box rust which is a fungus that affects and damages box plants.

Orange spots on Buxus (commonly known as box or boxwood) are typically a sign of a fungal infection called boxwood rust. This disease manifests as bright orange or yellow spots on the leaves and stems. Over time, these spots can grow and cause the leaves to drop prematurely, weakening the plant.

Boxwood rust harms plants by interfering with their overall health and vitality. The fungus Puccinia buxi causes the characteristic orange or yellow rust-colored spots on the leaves and stems of boxwood plants, leading to several detrimental effects:

Leaf Damage The rust spots disrupt the normal function of the leaves by damaging the chlorophyll, which is essential for photosynthesis. This can result in reduced energy production, leading to weaker plants.

Premature Leaf Drop As the infection progresses, affected leaves may yellow and drop prematurely. This defoliation weakens the plant further by reducing its ability to photosynthesize.

Reduced Aesthetic Value The unsightly rust spots and leaf drops diminish the ornamental value of boxwood, which is often grown for its dense, green foliage.

Weakened Plant Structure Over time, repeated infections can weaken the plant, making it more susceptible to other stresses, such as drought, pests, or additional diseases.

Potential Spread to Nearby Plants If not managed, the fungus can produce spores that spread to nearby boxwoods or other susceptible plants, creating a cycle of infection that can be difficult to break.

How to Manage Boxwood Rust

Managing box rust is really important as ignoring it will allow it to spread and potentially kill your hedge. Rust also acts as a vector for other illnesses in box hedges like blight or other pathogens.

1. Prune Affected Areas

Trim off and dispose of infected leaves and stems to reduce the spread of the fungus if only a mild infection, for more serious infections this may not be possible. Always use sharp clean secateurs when pruning box.

2. Improve Air Circulation

Thin out dense areas of the plant to promote better airflow, which can help prevent fungal diseases or prevent growing box plants in shady areas with little airflow.

3. Prune with clean tools

Whenever cutting box hedges make sure you use super clean sheers or secateurs and dip them in a mix of 1 part bleach to 10 parts water and dip the sheers into it as you move around the plant to reduce passing on any fungus or pathogens when hedge trimming.

https://youtu.be/_Dc3B2I7bu4

4. Maintain Good Garden Hygiene

Clean up fallen leaves and debris around the plant to reduce the chances of reinfection. Also prevent overhead watering in humid conditions and as soon as you see signs of illness hop to it to address it quickly!

Early intervention is key to controlling the spread of boxwood rust and keeping your Buxus plants healthy.

Do let us know how you get on!

Lee Garden Ninja