The Green Planet

More kinds of plants are crammed together in the tropical rainforests than anywhere else on Earth. The result is astonishing beauty and intense competition - a plant battleground. New filming techniques allow us to enter the plants' world and see it from their perspective and on their timescale. From fast-growing trees to flowers that mimic dead animals, this is a journey into a magical world that operates on a different timescale to our own.

Water plants create some of the most beautiful, bizarre and important habitats on earth. To hold on in torrents, plants use a kind of superglue. Some are armed with vicious weapons to fight titanic battles for space. Others form perfect spheres and escape from animal enemies by rolling. Where nutrients are washed away, plants turn into hunters of animals, laying traps and even counting to ensure their success. Brilliantly coloured flowers smother lakes, and in one magical river in Brazil, the water bubbles like champagne as plants create the atmosphere itself.

Between the tropics and the frozen poles lies a region dominated by relentless change in the form of the four seasons: spring, summer, autumn and winter. Each one presents plants with huge challenges, from ice and snow to raging fires; from intense competition to surprising enemies. This is a world of astonishing variety and vibrant colour. To survive here plants must use strategy, deception and remarkable feats of engineering. Most importantly, they must get their timing right.

Deserts are hostile; temperatures soar and water is rare. Yet plants find extraordinary ways to survive. They may grow imperceptibly slowly or travel the landscape looking for water. Others wait decades in suspended animation for rain to power an explosion of colour across the dunes. Desert plants protect their water stores from animals and from each other, using vicious spines, camouflage or by forging alliances with animals. Plants have invaded the most dangerous deserts on earth, overcoming salt, fire and toxic bird droppings to bring life and colour to these harsh landscapes.

We rely on plants for almost everything, including the air we breathe and the food we eat. Two in five wild plants are threatened with extinction, but people are finding new ways to help them, from projects in Africa to reseed the landscape to the rebuilding of a tropical forest in Brazil, tree by tree.