In a summit for the horticultural and forestry industry at Highgrove the Prince warned that millions of Britain’s broadleaf trees could soon be ravaged by Xylella fastidiosa, which can kill over 350 different species of plants. The oak, elm, plane and sycamore, as well as popular garden plants including lavender, rosemary and oleander are all at risk as the disease restricts their ability to draw water from the soil. Some garden retailers are not stocking polygala and oleander, while others are avoiding importing lavender and rosemary this spring.
The summit for horticulture and forestry industry experts was held to plan how to tackle the bacterial disease, which covers leaves in brown ‘scorch’ marks. In an impassioned keynote speech, he likened the threat from Xylella, which has already wiped out over a million trees in southern Europe, to ash dieback, the fungus decimating Britain’s ash trees. But when gardening guru Alan Titchmarsh asked over 100 delegates who could identify the disease on a plant only one hand went up – that of UK chief plant health officer Professor Nicola Spence.
The private event earlier this month was sponsored by the Royal Horticultural Society, the National Trust, the Royal Botanic Gardens, Kew, Woodland Heritage and the Duchy of Cornwall.
Devastating plant disease
In December, the RHS said householders and garden centres should not buy plants grown abroad to prevent the disease reaching Britain. The discussion was chaired by RHS vice president Alan Titchmarsh and other speakers included Environment Secretary Michael Gove. According to the European Commission, Xylella, which has no known cure, is “one of the most dangerous” diseases in the world as it devastates so many different types of plants. The disease is transmitted by insects including leafhoppers and spittlebugs but infected plants show few or no symptoms, so that the bacteria can easily be mistaken for common problems like drought or frost damage.
Call to action
Head forester Geraint Richards manages 1,700 hectares of woodland for the prince’s Duchy of Cornwall. He said: “Xylella would be major worry for our countryside and gardens if it came here because it has a wide and relentless appetite for so many different species. “In his speech, the Prince of Wales referred to diseases he has witnessed in his lifetime from Dutch elm disease through to ash dieback. He has a long-standing track record of being passionate about the environment and he really does know his brief. He is obviously a country man who loves his gardening and his trees and is desperately concerned that we find a way to control this onslaught of disease. He has tremendous convening power and his speech was very much a call for collaborative action, looking to the people in that room. So many people said to me ‘wow, what a speech’ and the response was all about this meeting being a pivotal moment and turning point.”
Award-winning garden designer John Wyer was among the delegates at the prince’s Gloucestershire estate. He said: “Getting all the key players in one room was Prince Charles using his influence in a really positive, apolitical way. Nobody is going to turn down an invitation from Prince Charles at Highgrove. I was very impressed by the depth and breadth of his knowledge and his drive and there was a real sense in the room of impending action.”
Mr Gove told delegates that failure to act would be like “sawing off the branch on which we sit”. The European Commission has already agreed his call for more checks on high-risk plants as they are moved between countries to try and halt the march of the disease. Delegates recommended setting up a cross-industry body to monitor plant biosecurity strategy. Other suggestions included a certification scheme for nurseries, improved training to identify the disease and traceability of imported plants and every organisation represented having a dedicated plant health officer.
Another proposal was a public awareness campaign at airports and Professor Spence is urging the public to play their part in preventing an outbreak. She said: “We really want to discourage the public from bringing back any kind of plant materials, whether it is seeds or cuttings, particularly when they are on holiday in Europe this summer because we are concerned that unofficial pathway could result in Xylella arriving here.” The RHS is calling for householders and garden centres to buy UK-grown plants rather than foreign imports. RHS director general Sue Biggs warned: “Xylella is lurking on the continent and it could come to get us at any time.” And Chelsea Flower Show designers are having to take special measures with Sarah Price scrapping olive trees, rosemary and lavender bushes from her Mediterranean garden for M & G. An outbreak in the UK would trigger all host plants within 100 metres being destroyed and restrictions on movement of plants within a three-mile radius for five years.
The disease had never been seen in Europe until 2013, when it was first found in Puglia in southern Italy. It has since wiped out more than a million ancient Italian olive trees, forcing a 20 per cent rise in the cost of olive oil across the EU. A million almond trees are believed to be currently infected on the Spanish island of Majorca and the disease has also reached Corsica, mainland France, Spain and Germany.
The disease is thought to have arrived in Europe from the Americas, where it is endemic, periodically wiping out entire vineyards and orange groves.