Struggling with box blight in your hedges or borders? Or maybe you're looking for precautionary measures to prevent it having seen it break out in neighbouring gardens. It's a common gardeners' woe, but luckily there are a few ways to keep your plot free of this fungal disease.
Many people learn how to grow boxwood as part of their garden design, and for good reason. The evergreen shrub is perfect for low hedging that can distinguish different zones without impeding views through the space. It's perfect for topiary, too, because it's dense with small glossy leaves and can be clipped into a whole host of shapes. It'll thrive in sun or shade as well.
Box blight, however, spoils the timeless look of these shrubs by creating unsightly dead patches. But, there are ways to reduce the risk of this disease taking over. And if yours are already infected, there are things you can do to tackle the spread, too.
How to identify box blight
First things first – you'll need to know how to spot box blight if you have it in your garden. The earlier you catch it, the less damage it can do.
A 'dead patch' is the classic look of box blight, explains Graham Rice, gardening expert and published author. "Branches die back and bare patches appear, creating ugly, dead areas in your hedge or topiary. It attacks small topiary and dwarf hedges more than larger specimen plants or tall hedges.
"Box blight can spread quickly, especially in wet weather," he warns, "and the first sign is leaves turning brown and dropping off. Check the stems, too, as black streaks often appear on younger ones," says Graham.
Graham Rice is a gardening expert, photographer, consultant and writer. He has published over 20 books on the topic and regularly features in the media.
How to prevent box blight
However you're using box in your garden, be it as plants for garden screening or to hone your topiary skills, then it's well worth knowing how to reduce the risk of box blight.
1. Trim your box shrubs at the right time, in the right way
Monty Don revealed some top tips on caring for box hedges and topiary on his website, which will help prevent blight.
Box needs clipping from time to time to keep it in shape. When you do so, check the weather forecast, says Monty – you'll need a few days of dry weather to do this task. The cut leaves and stems are more susceptible to the box blight fungus when the wounds are fresh, he explains. But, dry weather stops the spores of the fungus from being active, and leaves time for the wounds to scar over so they are less vulnerable to the disease. The start of summer is the time to give your box a trim, he adds.
Don't forget, however, if you are using box for hedges, you'll also need to check the best time to cut hedges, as there are rules and regulations in place to protect wildlife and birds in your garden.
It's also very important to ensure your garden shears or hedge trimmers are really sharp and clean. In fact, it's a good idea to clean your tools between pruning box in different areas of the garden – this helps avoid the risk of accidentally spreading any undetected blight. If you're using borrowed tools that have been used in another garden entirely, this step is imperative. And, once you've trimmed your box, remember to clean up the clippings thoroughly (laying a tarpaulin down first will make this easier).
As an extra safety measure, you may wish to apply a preventative fungicide before and after pruning, especially if you have had to deal with box blight in your garden before. You will usually need to apply it a good few days before you get trimming, and then wait a few days before applying again – check the product's instructions.
Shop these tools for keeping your box plants in good condition
With a high carbon steel blade for extra sharp cutting, the ergonomic handle on these secateurs also makes them comfortable to use
Collect any box cuttings in tarpaulin and make sure you clean the tarpaulin well after disposing of them
Keep your garden tools and working areas clean by using this solution once you've finished pruning
2. Provide plenty of ventilation where possible
Box blight thrives in shady, humid conditions and spreads quickly. So, ensure there is good airflow around your plants – this will help them to dry out quickly after rain. If your box makes up part of your cottage garden ideas, this means keeping an eye on nearby perennials, to make sure they don't start crowding your shrubs.
When it comes to watering plants, a drip irrigation system is best rather than using an 'overhead' approach as this will prevent the leaves from getting wet.
The RHS recommends adding a soft mulch beneath your box as well. This will prevent rain from splashing up onto the leaves and potentially spreading box blight spores. Refresh the mulch occasionally, to keep it disease-free.
Using mulch, such as this decorative bark mulch, around the base of your box plants will help to keep them moist and prevent box blight spores from spreading
3. Quarantine new plants
Box blight can enter your garden via new plants. Because of this, the RHS advises isolating any commercially sourced plants for at least four weeks before planting them, so you can be sure they are disease-free.
As they explain, some nurseries may use fungicides that suppress, but do not kill, the fungus. Quarantining the plants will give you enough time for you to check whether box blight becomes apparent.
Don't forget, you can also take cuttings from box and grow new plants. If you take them from healthy, blight-free plants that are already in your garden, there will be much less risk than bringing in a new plant from elsewhere.
Box blight treatment in 3 simple steps
Already spotted blight? You need these tips on box blight treatment.
1. Cut out infected areas
Box blight needs removing as soon as it's spotted, regardless of the time of year, as long as conditions are dry.
You have a few options. If it's just an isolated area that's affected, you can simply cut this bit out, cleaning your tools well before and after. In more severe cases, you can cut back the shrubs by half, advises Graham Rice. In the worst cases, you can cut the plants right back to ground level, he says. "Box blight does not infect the roots and new shoots will appear."
Alternatively, if you don't want the hassle of trying to save your box, or your attempts at cutting out infected areas seem to be in vain, you can simply dig it up for disposal. Just remember that a new box shouldn't be planted in the same place for a good while, as according to the RHS, spores can remain viable in the surroundings for at least six years.
Whichever approach you go for, Graham adds that tools and footwear should be cleaned afterward, to prevent spreading spores around your garden.
2. Apply a fungicide
As well as cutting back your infected box plants, it's a good idea to apply a fungicide. This can be done both before and after.
Spraying cut-back plants with a product such as Provanto Fungus Fighter Plus from Amazon, which should help stop the spread of the disease.
Fertilising plants can really help them bounce back, and box is no exception. Use a sulfate of potash monthly from mid-spring until early autumn which you sprinkle over the root area and water in.
3. Keep an eye out for further infections
As this fungal disease can spread so quickly, it's important to keep an eye on your plants even after box blight treatment. Unfortunately, it often reoccurs in places it was before, so keep vigilant and be prepared to re-treat where necessary.
What are some good alternatives to box?
If you're looking for an alternative to box for your garden, you might be interested in the trial that RHS Garden Wisley carried out.
It resulted in some top recommendations, including the common yew 'Repandens', Pittosporum 'Collaig Silver', Lonicera nitida 'Maigrun' (which has the benefit of leaves that look very similar to those of box), and Berberis darwinii 'Compacta'.
Other shrubs that make good swaps include Euonymus fortunei, Ilex crenata, and Pittosporum 'Golf Ball'. Graham Rice advises that, "most succeed better as medium to tall hedges than clipped regularly to keep them dwarf."
Alternatively, if quick coverage is your goal, check out the best plants for fast-growing hedges.
Shop alternatives to box
This shrub has similar looking leaves and structure to box
A similar shrub to box with pretty variegated foliage that lasts year-round
Of course, planting a hedge isn't the only way to create a garden boundary. Take a look at how to decide if a hedge or fence is right for you, and if you do end up choosing a hedge, make sure you understand how high you can grow your hedge when you have neighbours.
The original version of this article previously appeared on Gardeningetc, a sister website to Homebuilding & Renovating.
