Beat Box Blight with Curved Tops on Box Hedging

I have noticed box blight affects the top part of hedges and topiary more than the base. The top is where the fungal infection seems to thrive, causing the most defoliation and stem damage.

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My approach with box blight infections is to treat the hedge twice a year with a commercial grade fungicide and encourage the gardener or homeowner to adopt good gardening practices such as watering from the base, regularly sterilising clipping tools and clearing up as much fallen box leaf litter as possible.

So far this approach has had good success. The fungicide helps stop the infection getting worse and gives the box hedge a chance to recover. But unfortunately you can’t kill box blight. Once a hedge has become infected, it becomes a case of managing the disease rather than finding a cure. There is always a chance the infection will flare up again as fungal spores can remain active for up to 6 years.

The hedge in the photo above did recover. But as most of the damage from the blight infection was concentrated on the top, I was left with a hedge that had lovely new growth on the sides and twiggy patches along the top. So I cut the box hedge with a curved top using the fresh growth on the sides to hide the twiggy areas that were taking longer to recover.

This did improve the appearance and I also noticed the incidents of reinfection on the top were reduced. The repeated fungicide treatments were obviously a factor but it started me thinking whether cutting the box with a curved top was better for the health of the hedge?

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Before I explain my reasoning I should add there is not scientific basis behind this theory! It’s based on my experience of working with box hedging and topiary.

A flat top is the popular choice for box hedging. This has be the same for centuries. Parterres and knot gardens created with box hedging used to be meticulously cut with flat tops using hand shears. Now we have the luxury of battery and petrol powered hedge trimmers that over time create a far tighter finish on the box than hand shears. This looks great but has the downside of reducing the air circulation into the hedge and creating conditions perfect for a fungus to thrive in. Cutting the box with a curved top improves the air flow into the hedge and discourages the box blight fungus.

The main difficultly with this approach is convincing the garden owners as most still prefer the look of a flat top. Changing the fashion to curved tops will take time. Personally I like the look of a curved top but it doesn’t work on all designs. The flat top suits formal parterre designs whereas curved tops work on more informal, organic designs like the snaking box hedge in the photos below. What do you think?

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Supporting Hydrangea ‘Annabelle’ with Box Hedging

Hydrangea ‘Annabelle’ is a beautiful shrub. Large white balls of flowers on long stems from the end of July and into August. But this variety of hydrangea has a reputation for flopping due to the size of the flower heads. Wire supports help but they don’t look great.

A natural support is box hedging. I was inspired by the photos of Gina’s garden on Instagram to plant Hydrangea ‘Annabelle’ in a front garden that has borders edged with tall box hedging.

Two years on, the hydrangeas have established and look stunning. Billowing clouds of white flowers contrast beautifully with the green of the box hedging. Some of the hydrangea stems are holding each other up as they have grown densely together. Others flop gently on to the box hedging.

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As the hydrangea flowers fade, they turn a lovely bronze colour that looks particularly good on a frosty winter’s morning.

Usually box hedging is not happy when crowded out by herbaceous perennials. Patches of dieback can appear. This often happens with perennials like geraniums that put on lots of foliage early in the season, and block out light and air flow to the low hedging. However, box hedging copes well with Hydrangea ‘Annabelle’ as the flower heads only start flopping when they are full sized in mid to late July. This gives box enough time for the new Spring growth to harden off. As the flower heads age, they lighten and lift off the hedging enabling better air circulation- an important factor to discourage box blight.

The box hedging needs to be at least 60cm high to provide adequate support. Any lower  and the hydrangeas will fall straight over it. In early Spring cut off the old flower heads to the nearest two strong buds, rather than cutting the Hydrangea ‘Annabelle’ back to the ground. This helps the stems to thicken and become stronger to hold up the new flower heads.

Trimming the box hedging can be a little awkward. Carefully tie the hydrangea back using string and posts, lifting the flower heads off the hedging enough to allow access for the shears or trimmers. But still be careful as it’s very easy to cut a hydrangea stem by mistake. On the plus side, Hydrangea ‘Annabelle’ make lovely cut flowers for the house.

If you have a box parterre or border edged with box hedging then I definitely recommend Hydangea ‘Annabelle’ for a low maintenance planting solution that has maximum impact. They will need regular watering, especially if we have a summer that has been as dry as this year. But it’s worth the effort when you can enjoy the results.