Sunday, November 30, 2008

Watering in the dry

Summer has arrived in all its blazing glory over the past week or two. The lawns, which had needed mowing every four or five days, have suddenly browned off, and the vegetable garden is requiring a lot more attention – watering and weeding wise.
The arrival of the summer season also coincides with the instigation of watering restrictions in most parts of New Zealand. Many councils have (wisely in my view) decided that the best way to cope with the excess demands placed on their water supply systems by introducing watering controls on a calendar basis rather than water-flow. It is a good reminder to us gardeners that we need to be mindful of water conservation right through the gardening year, and with all of our gardening practices.
One way we can help ameliorate our garden’s water requirements is by being clever about the plants we use in our gardens. If you live in an area that gets very warm, and you have thin, dry soils why would you try and grow camellias, rhododendrons and other plants best suited to Taranaki type conditions? Instead look out for those trees and shrubs that will cope better with your conditions.
Among the obvious places to start looking are parts of the world that have similar growing conditions. From the Mediterranean we might select olive trees, rosemary and lavender bushes, and some of the delightful Cistus family, with their bright white and pink flowers. All of these will cope well with our summers, and will provide good colour.
We might also look to South Africa, where many members of the vast protea family reside. Among those that will do well in our climate are the Leucodendrons and Leucaspermums. The latter, with their spidery flowers, are not as common as the former, but provide lots of colour throughout the year.
From our Transtasman neighbours, we could select some from the vast number of Grevilleas. There are Grevilleas for most situations, from the gigantic tree G. robusta, the orange Silky Oak (actually, not silky and not an oak, but that is Australians for you!) right down to ground covering types. Most of these are well suited to growing in dry areas, and with a little imagination, can be turned to all sorts of uses. I was taken with a Grevillea hedge I saw recently – so much more fun that a box hedge, although not as fashionable.
For lower down in the plantings, you can probably do worse than looking for a daisy, as many of them are adapted to growing in dry areas. I have some Gaillardias and Coreopsis, both North American species, happily growing in a north facing bed that also grows South African bulbs very well. Gazanias, Osteospermums and Arctotis, all from South Africa, will cope with even hot situations. I have some planters that are filled with Gazanias, and they are already showing of their full range of colour.
There are, of course, some areas where we want to grow plants that are going to require some extra watering. The secret here is to make the best use you can of the opportunities you are given to water, and to optimise the effectiveness of your watering.
One simple thing you can do is to water when the weather is cool and calm. There is little point in watering on hot windy days- the water will not be used effectively at all. You are better to water in the cool of the evening, or in the early morning. Best of all, wait until it rains. That is the ultimate watering time.
Try to water as slowly as is practical. A steady slow flow will all be absorbed while a strong flow of water will cause run-off. There is no point in applying more water than the spoil can take up.

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