Even in this damp, rainy country, mains water is increasingly precious. Plant accordingly
I want to discuss something today that I've written about loads of times before. But there are some things that you can't say often enough: look both ways when you cross the road, brush your teeth before you go to bed, close the door so you don't let all the heat out. And don't waste water in the garden.
In Ireland? In damp, rainy Ireland? Well yes, I'm afraid so, and especially if you live in an urban area with mains water. In Dublin, for instance, the building of new homes and commercial developments has put pressure on an already creaky, leaky system. We don't have a huge amount of water to spare right now, and if we get a dry summer, we'll have a whole lot less.
A summer drought is predicted for England, where hosepipe bans have been in place in the southeast since the beginning of April. At the Royal Horticultural Society's Chelsea Flower Show, which opens to the public next Tuesday, water conservation is high on the agenda, with several of the gardens designed so that they need little or no irrigation. And the RHS, which promotes low water usage, is practising what it preaches: water for the exhibitors' gardens and nursery stands won't come from the mains, as in previous years. This year, it is being extracted from the ground via a 100-metre-deep borehole, which cost £45,000 (€65,565) to drill. No more than 20 cubic metres (4,400 gallons) per day (1 per cent of the volume of an Olympic swimming pool) will be pumped up during the month of May.
Alas, drilling for water isn't practicable in the average garden, which makes it all the more important to be mindful and miserly about its use. If your water comes from a mains, it's worth remembering that every drop you draw from a tap or hose has been processed and purified. It would be a shame to fritter it away mindlessly. In other words, the sooner we start thinking of water as a precious commodity, the better (although I suspect this mindset won't evolve until mains water is metered and charged for).
The very first place to start getting more value from your water is not - as you might think - at the end of the hose pipe, or anywhere near it. It is, in fact, in the soil. In many gardens, especially urban ones, the ground underfoot is tired and dry, with no substance to it. Water either runs straight off the surface, or it evaporates at the first hint of sunshine or wind. An ideal soil, on the other hand, behaves like a sponge, soaking up whatever rain the weather throws at it, and holding it safe within its structure - where it provides liquid refreshment to plants over a long period of time.
The secret to achieving such moisture-holding beds and borders is to add humus: any organic matter such as well-rotted farmyard manure or home-made garden compost. If you're digging a new bed, add plenty of humus; if you're putting in a new plant, add plenty of humus. Or if you have an old bed, add a layer of humus to the top, and let the worms do the digging for you.
Humus, especially your own garden compost, not only allows the soil to hold a vast reservoir of moisture without becoming waterlogged, it also inoculates it with beneficial bacteria and a host of other tiny life forms. These minute organisms - and worms too - colonise the soil, and get busy ploughing it, eating it, excreting it, eating each other, excreting each other and generally having a bash. All of this is terribly good for the soil, and for plants. Compost-fed plants are more likely to grow healthily, and are better able to resist disease and drought.
Once you've got your soil in shape, you're going to want to keep it that way. A layer of mulch, applied to the surface after rainfall, is the best protection, locking moisture in and preventing weed growth. Organic mulches (which eventually rot down into the soil) include grass clippings, straw, cocoa shells, leaf mould, wood or bark chippings, and even newspaper. Use several layers of the latter, dampen it thoroughly, and - if you like - disguise it with grass clippings (excellent in vegetable beds).
Gravel or horticultural grit looks good as a mulch in containers, and is perfect for alpine and Mediterranean-type gardens - where it needs to be topped up every couple of years.
But what to plant? Chose drought-tolerant species, from arid regions such as the Mediterranean, Australia, New Zealand, southern Africa, California, and from prairies, steppes and coastal areas. If you don't know where a plant is from, then its leaves will tell you if it can cope with dry conditions. Look for foliage that is small and hard (such as rosemary and thyme), greyish and furry (lambs' ears), bluish and waxy (eucalyptus), fat and succulent (sedum) or leathery (bergenia).
Although a dry summer is predicted for Britain, we don't know what our own weather will be. But it makes sense to plan for drought. So, make like a boy scout, and be prepared.
A leaflet entitled Water Conservation in the Garden is available from the Royal Horticultural Society of Ireland, Cabinteely House, Cabinteely, Co Dublin (01-2353912); www.rhsi.ie.
For information on conserving water and on drought-resisting plants and gardening see the (British) Royal Horticultural Society website: www.rhs.org.uk/advice/watering.asp