Have you seen a fat, juicy earthworm lately? If you live anywhere between Gisborne and Oamaru then you are either very lucky or a very dedicated and skilled gardener. In Canterbury the drought continues with no sign of relief, and is now the longest on record. Other parts east are not much better. Welcome to global warming.
Adding George Dubya Bush, the makers and drivers of ‘Remuera tractors’ and other gas guzzlers, and anyone else known to advocate, practise and defend still further excessive emissions of carbon dioxide, to the league of garden curses (up there with twitch, convolvulus, spittle bug and other nasties), may relieve one’s feelings temporarily. But is there anything we can do to garden as though we will see less and less real rain in our lifetimes? (Just as we have had to adjust to the still increasing hole in the ozone layer.)
Drought Tolerant Gardens
While we wait (and hopefully work) for the collective and political solution to climate change, there is quite a lot we can do to make our gardens drought tolerant, without going the full cactus and succulent route. The first and most important step is to reduce the area of exposed ground growing thirsty plants. In most New Zealand gardens this is the lawn area. The grasses we grow there didn’t evolve here and need extra water to look their best when they get cut. In a previous column (‘Life beyond the lawn’, April 2000) I discussed the alternatives to thirsty lawns, from hard paving and wooden decks for surfaces to sit out on, to native tussock grasses for a beautiful ground cover that doesn’t block the view. Other areas, where neither sitting out nor the view are important, can be become shrubberies.
Shrubs and small trees have the additional benefit of providing shade and thus keeping the ground cool. Their fallen leaves also provide welcome mulch. Choose and site your shade trees wisely. Deciduous trees with thin trunks and open branches (like birches and magnolias) are best for the northern aspects of the section, where they will shade the house in summer but not block welcome sun in winter. Any remaining lawn should also have a big shade tree, where adults can sit and children can play in comfort and safety. Evergreen trees are fine for the southern side – natives like pittosporums, ribbonwoods, akekake and olearias are good choices.
Flowers for Dry Times
But what about flowers? Flower borders need rethinking, with a shift from thirsty annuals like begonias and petunias, and delicate perennials, to ‘self-care’ annuals like poppies, cornflowers and marigolds, truly hardy perennials, and small flowering shrubs. My main border, which is in full sun, is still flowering happily, with the prize going to the perennial salvias. I am growing pale blue S. azurea, mid-blue S. patens and deep blue S. guarantica at present, but there are lots more equally gorgeous and strong varieties to choose from.
The butterfly bush, Gaura lindheimeri, is another tough but beautiful border plant, which is smothered in white flowers for four months. Chrysanthemums that were planted in good compost are doing well and the tall scabious keeps on keeping on. But my pride of the border is the lion’s ear plant, Leonotis leonurus, which has bright orange furry flowers, growing in whorls from tall stems. Very unusual and, as a South African, very well-adapted to hot, dry conditions. Scrambling along the front of the border is one of the desirable convolvuluses – C. mauritanicus (syn. sabatius). This one is from Morocco, and has purple blooms for six months of the year no matter how dry it gets.
The Silver Leaved
To shelter and set off the bright flowers I have silver-leaved plants, of which my favourites are Helichrysum petiolatum, Artemisia ludoviciana ‘Silver Queen’ and the shrubby convolvulus, C. cneorum. The Artemisia and Helichrysum families are good places to find more dry-tolerant species – the herbal artemisias wormwood and southernwood are tough cookies, as is the herbal helichrysum, the strongly-scented curry plant.
Flowering Border Shrubs
For shrubs for the border that are drought tolerant but also good flowerers I lean heavily on natives – Olearia cheesemanii is smothered in small white daisies in spring while the Marlborough rock daisy, Pachystegia insignis, has to be one of the most dramatic and impressive flowering shrubs of all time. There is a hebe for every season, and I am especially partial to the so-called ‘NZ lilac’, Hebe hulkeana, another toughie from Marlborough with deceptively glossy round green leaves and the most delicate, frothy sprays of palest mauve flowers. My second favourites are the Cistus family, especially the New Zealand raised ‘Bennett’s White, with its particularly large white flowers with yellow centres and its sticky bronze stems. However, this gets to be quite a large bush, so it’s for the back of the border only. C. ladanifer and C. ‘Silver Pink’ are good choices for the middle of the border (but don’t let them get crowded by other shrubs) and C. salvifolia is perfect for the front edge. Where it teams nicely with its ‘sun rose’ cousins the Helianthemums, in a range of warm shades.
Dry Weather Care
As well as choosing the best plants, be sure to give them the best treatment you can manage. My full sun border was mulched first with compost and then with pea straw, each layer well watered in. But now I water it once a week only, and it keeps on giving.
Next month – the drought resistant food garden