Mimosa is pretty…but ‘posing threat to biodiversity’ in south of France
The flowers are prized in the region, but not everyone is thrilled to see their spread
Mimosa is emblematic of the south of France, but it is invasive, and can cause allergies
KATE TARTACHNA/Shutterstock
Mimosa is well-known in the south of France for its pretty yellow blooms – and there is even a festival in its honour in Var – but experts have warned that the plant is actually an invasive threat to biodiversity as it originally comes from Australia.
Prized plant
Mimosa was first introduced from Australia to England in 1792, where it was prized for its look and smell. It was then cultivated in France, and has been seen in the natural environment – particularly around Cannes and the wider Alpes-Maritimes area – since the mid-19th century (1800s).
It was immediately welcomed by the region, particularly by the famous perfumers in Grasse (Alpes-Maritimes).
Today, the town is even linked to Bormes-les-Mimosas (which was known only as ‘Bormes’ until 1968) by the famous ‘Mimosa Route’, a 130-stretch of road along the Côte d’Azur that links several towns that have impressive mimosa displays or celebrate the plant in some way.
For example, Mimosa-decorated floats pass through Bormes-les-Mimosas every year, during the Grand Corso du Mimosa festival.
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Every year, an average of 200 tonnes of the blossom – or 18 million stems – are picked and processed in Alpes-Maritimes and Var. They are used in everything from perfumes to chocolates to sugar syrups, and more. Their season lasts until the end of March.
Botanical blacklist
Despite this celebration, mimosa has actually been placed on the blacklist of invasive alien species by botanical association le Conservatoire botanique méditerranéen de Porquerolles.
“Mimosa causes us a lot of concern. It has a significant impact on our ecosystems,” said Camille Casteran, sector head at the Port-Cros National Park, in the Var, to FranceInfo.
The plant is considered to be invasive, not only because it does not originate in France, but because it can quickly ‘take over’ an area if left unchecked, and cause problems for native fauna and flora. For example, it can emit toxic substances that can limit the growth of other vegetation.
“This plant is monospecific in the area it colonises, so it is the only species which will develop,” said Mr Casteran, adding that this can have negative effects on the Mediterranean ecosystem.
Similarly, regional animals such as the Hermann's tortoise - one of the most endangered reptiles in Europe - can be threatened by wide expanses of mimosa.
“The mimosa's takeover of these environments is problematic because [the tortoise] needs open spaces for its herbaceous diet and its eggs need to be exposed to sunlight,” said Mr Casteran.
Mimosa is also not easy to remove; pruning or cutting does not help, as it does not develop from a single seed, but from root offshoots. Cutting it therefore means that more offshoots will grow.
It is also resistant to fire, and its growth can even be stimulated by flames. It can spread fire easily which makes it a dangerous plant to have in wildfire-prone areas.
“The mimosa is a walking powder keg,” said Mr Casteran. “It has evergreen foliage and very little moisture, so it will rise in temperature very quickly.”
Residents and authorities in France are warned to clear undergrowth and excess plants from their gardens and open spaces every year in a bid to reduce the risk of fire (a process called débroussaillage), but mimosa can be extremely tough to remove.
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“As soon as the undergrowth is cleared, the mimosa establishes itself and it is then difficult to dislodge it,” said Mr Casteran.
The park’s workers do not use weedkillers or chemical treatments as they do not want to cause damage to the plants and animals surrounding the mimosa.
One surprising way of getting rid of mimosa is to use donkeys, as they enjoy eating it, said Mr Casteran.
Despite these difficulties, mimosa remains very popular in garden centres and in florists, and there are no legal restrictions on its sales. However, beware: despite its prettiness, the plant’s pollen can also cause severe allergies.
Read more: Large increase in maximum pollen alert levels in France
