Andrew Atkinson talks to Felix Albaladejo (pictured) proprietor of Garden Felix in Los Montesinos about plant invasive species and pests diseases, ahead of the 2020 Chelsea Flower Show.

THE processionary caterpillars in Spain are once again upon us – just one of the invasive species and pests out of control – that will lead to a change in gardens in future years.

Future gardening problems have been flagged up facing plants from pests and diseases, including the bacterium Xylella fastidiosa, deemed at risk of infecting cherry, hebe, lavender, oak and rosemary.

“Xylella fastidiosa is a great threat to Mediterranean agriculture, it is a bacterium that affects multiple plant species such as almond trees, olive, rosemary, vines and oleanders, among others,” said Felix.

The pernicious disease has devastated the olive groves of Europe – causing leaf scorch, wilt, dieback – and ultimately plant death.

In 2018 olive trees in Italy were hit by the deadly Xylella plant disease that spread across the Mediterranean olive growing regions – including Spain.

“It is a disease that causes no cure. Only by eliminating the plant – that is the only solution,” said Felix.

IlSalento, in southern Italy’s Puglia region the disease wiped out hundreds of olive trees, with the number of trees infected with the Xylella fastidiosa bacterium quadrupled.

The bacterium spread from its containment zone in the agricultural area of Valle d’Itria to the coastal plain of the Piana degli Olivi Millenari, home to some of the oldest olive trees in Puglia.

Garden Felix
Garden Felix

Spanish authorities reported they had found a Xylella infected olive tree on Spanish mainland, near Madrid.

The disease had earlier been discovered on the Balearic island of Mallorca.

Xylella expert Alexander Purcell from the University of California at Berkeley said other strains of Xylella were found in all of the other Balearic Islands.

Xylella also hit France in spring 2018. The Interprofessional Union of Oleiculturists reported that olive trees on the island had been infected.

The disease was found in Corsica and in ornamental plants in the French Riviera in 2015 but, at the time, it had not spread to olive trees.

Xylella was introduced into Europe through tropical plant imports from Central America, where it has attacked citrus, coffee, grape and alfalfa crops.

The International Olive Council said the Mediterranean Xylella outbreak led to a global drop in olive oil production in 2017.

As in Spain, in Britain plants are and will continue to be affected by diseases.

Gingko, used as a resilient tree, is a plant vulnerable to Xylella Fastidiosa: “Growers are impacted by climate change and have to find new ways to grow,” said Sue Biggs, director general of the RHS.

At the 2020 Chelsea Flower show, during May 19-23, gardeners are not allowed to use oak trees or saplings, due to the threat of the Oak Processionary Moth, along with non-native lavender, because of  Xylella fastidiosa, established in lavender plants in Europe.

Some Chelsea Flower Show exhibitors have sourced lavender from the continent.

“It is killing millions of plants here – detected in almond trees in northern Alicante,” said Felix

“Xylella fastidiosa multiply the interior of the plant, obstructing the circulation, causing its death,” said Felix.


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