Summer in the gardens means the arrival of drought and heat, sparsely punctuated by a few storms that are always very welcome for the vegetation.
In the shade of the Mediterranean sun, in the hollow of the valley, respite is to be found under the tree ferns of the New Zealand landscape, in the bamboo forest in the subtropical Asian landscape, by the waterfall, or in the meadow in the subtropical American landscape.
How plants adapt during summer
Plants are forced to find solutions to the lack of water and desiccation. It is not so much the certain heat but the irregularity of the quantity of water available that makes this season so harsh. Plants adopt a wide range of strategies, which can be observed in the landscapes evoked in the Jardin des Méditerranées.
There are those that prefer to disappear, spending the harsh months either as seeds or buried in the soil as roots, rhizomes or bulbs. There are those who live in slow motion, often keeping their leaves tough, small, or hanging down so as to expose the least amount of surface area possible to the sun at its zenith. There are those who slowly distil their essential oils to better retain their water. And there are those who take advantage of the nocturnal cool to bloom at night! They join forces with nocturnal pollinators, mainly butterflies in the Mediterranean region and bats in other lands.
Fire in the Mediterranean region
In summer in the gardens, the guides tell of the plants’ struggle for water in order to survive – a motionless and invisible struggle that nonetheless requires perfect adaptation.
And as soon as the west wind blows, fire spreads. Mediterranean vegetation is dependent on fire for its renewal and reproduction. All Mediterranean plants are adapted to the passage of fire.
Naturally, as it ages, vegetation accumulates dry wood following the drought cycles typical of the Mediterranean climate. When summer heat rises, the essential oils that plants release to withstand desiccation are highly flammable.
Some plants are only passive, such as the cork oak and nolina with their barks made of cork.
Some of them, such as arbutus and tree heathers – survive the passage of fire thanks to their subterranean trunks known as lignotubers.
Others need fire in order to reproduce – either fire brings on flowering, or the chemical compounds of smoke encourage seed germination.
After a fire, people see only the devastation of familiar landscapes, whereas plants take advantage of this redistribution of space and access to the sun to reproduce, germinate and rejuvenate.