It’s not just the drought that’s making the gardens look very dry and brown this year. You’ll notice that much of our 600 metres of box hedging and topiary is looking decidedly dry, bare and positively skeletal.
This is not just lack of water nor is it box blight it is the result of Box-tree caterpillar infestation, Cydalima perspectalis.
Many local people have been telling us of their own experience of the devastating effect of the Box tree Caterpillar. For the last two years we hoped we’d kept the box tree Caterpillar at bay. You will have seen the little green jars hanging from shepherd’s crooks around the Gardens over the last couple of years. These are part of our integrated pest management system which includes biological control and changes to cutting regimes. However, the exceptional dry and sunny weather this spring seems to have benefitted the moth -which has at least two, sometimes 5 reproduction cycles just in one season.
We heard from other colleagues in the heritage gardens sector just how quickly box moth could devastate hedges. But even we were shocked at the speed of change. Earlier this season our Gardeners started implementing their emergency plan. Identifying some of the hedges that could be replaced by fencing or other plants, they have grubbed out, or cut down to the ground, smaller hedges around the gardens. You may not have noticed the loss of small hedges in the Melon Grounds and around the North wall borders. We have concentrated on trying to save those hedges and topiary which epitomise the early 18th century style of the Gardens.
What will happen?
Unfortunately, it is likely that more than 1/2 or up to 3/4 of the hedges will not survive this summer. While some will revive, even if cut down to the ground, they will still be vulnerable to the box tree Caterpillar next year.
The gardens community across northern Europe have been experimenting and researching over the last five to 10 years on alternatives to box. Everyone recognises that there are very few other plants as flexible and as useful as Box – especially when it comes to heritage and historic garden style.
We’re still listening and learning from other places, in the meantime we are replacing some edging with hedge germander, Teucrium lucidrys, which while pretty, cannot be used as a ‘proper’ Hedge. We are also trying to raise funds to purchase thousands of Yew plants to replace at least the parterre on the far South wall border. This parterre is in the shape of our trust’s logo, so we can’t really lose it. We hope you will bear with us while we find affordable and resistant replacements.
The Box Moth was first identified in Britain in 2007 and has now reached most of the UK. Originating in warmer climes, the Box moth is just one of many changes that are a result of climate change across the world. The moth has very few natural enemies, but there are sightings and observations that northern european birds are beginning to recognise the caterpillar as an acceptable food source. We can only hope that overtime adaptation will occur.
While adaptation often takes a long time to develop, there is hope. For example, the disease Ash Dieback devastated many trees over the last decade or so, but there are now signs that naturally resistant varieties of Ash are appearing.
In the meantime, the Gardeners will try to manage our hedging as well as they can and we will continue to fundraise for replacements. We are also keeping a weather eye (sic!) out for how the drought this year is affecting the different varieties of apples and pears in our two orchards. Many of the trees are showing signs of acute distress and are dropping their fruit before time. How this will affect this years yield and the production of fruit juice we don’t yet know.
Our hearts go out to farmers across the country whose crops and herds are suffering already, with many winter crops, put aside for animals in the winter having already failed. We are proud to be able to preserve the biodiversity of ancient fruit varieties through our two historic orchards. While we are not a Botanic or scientific garden, we hope we can nevertheless play some part in supporting future food security in the face of climate change.
