How did you garden grow this summer? Was it dry and scorched on hot sunny days, especially when the wind blew. There are lots of plants that wilt as soon as it becomes hot and dry, and the wind makes them even thirstier.
Water is one of our most important resources, and it is one that is becoming more and more scarce. In many areas of the world there is just not enough water to grow crops, or gardens as we know them in New Zealand. A tomato plant needs about 115 litres of water in one growing season. Roses are gorgeous but thirsty.
It's important to learn to garden without using litres and litres of water, understanding how plants adapt to survive with only a little water helps. Then you can make a difference by growing plants that don't need as much additional water.
Deserts Deserts are found where there is not enough water for most plants to grow. They cover about a third of the world's surface. The driest desert is the Sahara Desert in North Africa, where some areas get less than 1mm of rain each year. The Atacama Desert in Chile is also very dry and rain can fall only every few years. There are desert areas on all the major continents. In New Zealand, we have several very regions that are very dry, especially in summer.
Desert plants show us that nature has worked out some clever strategies and that there's a reason that cacti look so, well weird, compared to other plants.
How Desert Plants Save Water Desert plants have to be their own water tanks and collect as much water as possible from storms and rain showers.
Cacti and succulent plants often have swollen stems and no leaves, and this reduces water loss from transpiration (to find out about transpiration see our rainforest project). We've all seen ice plants at the beach, with fat grey-green spikes for leaves. If you bruise them, those leaves are full of moisture, moisture that they are storing.
Some plants are almost elastic, expanding to hold water when rain falls and then using it slowly over a long period. For example, cacti with ribbed stems can expand after rain to hold as much water as possible.
Some plants catch water in their saucer-shaped leaves, giving them a chance to absorb after the rain shower has passed. Sedums grow in rosettes that catch the water, which they can then soak up.
Reaching Water Some cacti have hugely long roots that reach far down into the soil in search of precious moisture. Mesquite bushes that grow in North America have roots that reach down 10 metres (33 feet) and other plants can go even deeper.
Spikes and More Grey silvery plants can reflect sunlight, keeping the plant cooler, and plants covered with tiny hairs help to trap beads of moisture and slow evaporation. And those painful spiky, spines? They are protection from animals that eat plants for the food and moisture they contain.
Fast Living Many desert flowers have very brief lives; they grow as soon as the annual rains fall, flower, set seed and then die away when the moisture from the rain dries up. The plant survives the dry by spending the dry period as a seed, germinating and blooming again when the rain falls. In very dry areas of Western Australia and South Africa the blooming of these wildflowers is spectacular, although brief.
Succulent 'Echeveria' are easy to grow and come in lots of wonderful shapes
There are plants that grow in the desert and very dry climates enjoy the dry, plants that have developed special strategies for coping with the dry. These plants make great container and pot plants.
Cacti and succulents love the dry. You can easily buy cacti and succulents, or get a small piece with roots from a friend's plant. (Never take ice plant from the beach; it's doing an important job of stopping the soil and sand from being washed away!)
Plant your succulent in a pot of loose gritty soil with some larger pebbles in the base. This will enable the water to drain through the soil easily and stop any rot in wet weather. It also means the soil doesn't freeze into a block of ice in winter, making your plant very tough and able to cope with freezing temperatures. Don't use a saucer underneath the pot, this encourages water to collect in the bottom of the pot.
Pebbles or gravel used on top of the soil makes a 'mulch', helping to keep the soil moist below and prettier than the dry soil.
Water it gently to settle the soil around the roots. And place in a warm sunny place. Water the plant every week or so until it is established, that is, until it begins to grow. Then leave it alone to grow by itself as most succulents and cacti will receive enough moisture from rainfall.
If you have a wide, saucer-shaped pot you can make a little desert landscape with two or three different plants, just like ours.
Sedums form rosettes to catch water
Escholtzia, the Californian poppies, flower after the rain
Clever and Successful Plants have developed lots of clever ways of living on tiny amounts of water, and there are lots a fascinating plants we can grow that don't guzzle gallons each day.