It’s official – weather agencies on both sides of the Pacific agree that a new El Niño weather event is forming**. And it looks like it could be as bad as 1997, with NASA climate scientist Bill Patzert dubbing it a “Godzilla’ El Niño”. For those of us in south-eastern Australia, that means a long, hot, dry-as-chips summer. Although we’ve had several summers in Sydney that have been cooler than normal, we always knew that the next El Niño was lurking out in the Pacific somewhere – a bit like the proverbial Kraken coming to wreak havoc on our gardens.
Of course, one side’s of the Pacific’s drought is another’s wet weather, and Californians will be greatly relieved to know that after several years of parching drought, their rains are likely to return next winter, at the end of 2015. However, Patzert says be careful what you wish for as those rains could well be like a “fire hose” coming at you, with floods and mudslides and hurricanes, just like in 1997.
In eastern Australia, it seems like it’s dried up overnight. July had less than half our regular rainfall, and there’s been almost no rain in August at all. And the daytime temperatures are creeping up and up. In eastern Queensland its even worse, with no rain for many months, and many gardeners without town water already despairing of keeping their garden alive.
What have I been doing in my Sydney garden to get ready for El Niño?
In my garden, I’ve been taking advantage of the past few milder and wetter years to do some major restructuring in my garden planting and infrastructure preparation, knowing that more El Niño years are always on the cards and, with climate change, that they will become deeper and more frequent.
I won’t be making a xeriscape (no irrigation) garden as I’m a plant lover, and there will always be something beautiful and a little bit more water-precious that I can’t bear to be without. But during those drought-stricken and very hot summers, I observed carefully which plants in my garden managed to cope with minimal supplementary watering.
1. I’ve planted shrubs
Those who sell perennials will trumpet their drought-hardiness – and some are, no doubt, very reliable in more clayey, water-retaining soils and southern and inland climates – but as far as my Sydney garden and its shallow, clay-sand soils and drying coastal winds is concerned, drought-hardy shrubs are much, much tougher and better suited to our dry-spring and humid-summer, cool subtropical climate.
Many drought-hardy perennials come from Mediterranean climates and are adapted to environments with low summer humidity. In Sydney, even after many days without rain, the humidity can be well over 70%, so these perennials succumb to fungal diseases like rusts, mildews and moulds. And the others get eaten by rabbits!
So I’ve given up on drought-hardy perennials like Agastache, some salvia, sun jewels, calibrachoa and verbena.
Shrubs also have other big advantages over perennials. They are lower maintenance, usually requiring only a few trims each year or an annual shaping prune. Many grow naturally to a pleasing rounded or dome shape and need nothing done to them at all, unless you’ve a mind to keep them smaller than they’d like to grow.
Shrubs also create permanent structure in the garden and that’s an important part of our Sydney-style of gardening. If you want mass and volume in a particular area, a shrub’s mass stays there all year round. They don’t disappear with the first whiff of a colder winter, or need to be cut to their knees for a seasonal rejuvenation. That cut down is fine if you live in a climate where you just don’t go outside for several months and you happily ‘put the garden to bed’.
But in a warmer climate, there isn’t that climate down time. We dine outside on our winter sun-drenched back deck in Sydney all year-round, enjoying day time temperatures that my Scottish cousins think are balmy and barmy. I don’t want a garden of bare sticks when I’m still outside enjoying it.
A shrub’s bulk and extensive root system is also especially useful in shallow sandy soils like mine, as it can survive long periods without extra water, it shades its own root zone, and its woody stems are less prone to drying out. Those woody stems also support the plant even when the leaves are wilting, where lax perennial stems will bend over and be permanently damaged.
So after observing how many perennials went to the gods through the Millennium Drought, or struggled in the years after with Sydney’s feast or famine summer rainfall and high humidity, I have taken advantage of some cooler and wetter seasons to reef many of them out and plant more shrubs.
Shrubs that I’ve kept, or planted: Murraya paniculata and its cute little cousin Murraya ‘Minamin’; Duranta ‘Sheena’s Gold’; Grewia ‘Lavender Star’; Raphiolepis ‘Springtime’ and ‘Snow Maiden’; Carissa ‘Emerald’s Star’; Syzygium cultivars ; Abelia ‘Snow Showers’ and ‘Kaleidoscope’; bougainvillea, Pittosporum ‘Miss Muffet’; Weigela floribunda; Justicia brandegeana; Megaskepasma erithroclamys; Leucospermum; Grevillea johnsonii; Davidsonia pruriens, Helichrysum petiolare + ‘Aurea’; Acmena/Syzygium ‘Hot Flush’ and ‘Allyn Magic’; Cuphea ‘Tiny Mice’, Pentas lanceolata; Adenanthos sericeus; Loropetalum cultivars; Euphorbia Poysean hybrids and ‘Diamond Frost’; loads of shrub aloes from aloe-aloe Horticulture; Callistemon, Grevillea rhyolitica; Nerium (oleander) dwarf cultivars; and that good old stand by, Nandina.
Selected shrubby salvia are good in Sydney (see Deirdre Mowat’s iGarden Salvia page) for the best selection). I find the ones with smaller, leathery leaves, like Salvia semiatrata are the most drought hardy. I’ve avoided camellias as although they’re great plants in a drought, possums literally eat my camellias to death.
If you want a looser, ‘perennial look’ I like to use some of the more shrubby climbers that have wiry stems and that quite liked being clipped, like Trachelospermum ‘Tricolor, Hardenbergia ‘Minihaha’ and Chorizema cordatum in sun, or Cissus in shade.
2. I’ll be reserving most of my dry-season watering for my trees
Trees are your garden’s most valuable assets especially in a warm and subtropical climate like Sydney. First, they are expensive to buy, and by the time they’ve been growing for a few years, irreplaceable. People will squander water (and hand-watering time) on cheap annuals or a small perennial they see wilting when they can be easily replaced in a quick trip to a plant nursery. But it doesn’t occur to them to deep water their trees. Those trees are very resilient through short droughts but when it’s dry month after month, those big guys really start to suffer, mostly in silence. The neglectful tree-owners will wonder why, a few years down the track and usually after the drought has broken, their trees start dropping twigs, then branches, or even blow over in a storm. Trees can take years to die and, when they do, the most likely cause in a warm climate was that during a drought their owner didn’t look after them, and that neglect caused a large percentage of the tree’s roots to die. But the owner will, of course, blame the inherent danger of trees when it becomes unstable and unsafe.
3. I’ve put in as many water tanks as can fit
Although Sydney doesn’t currently have water restrictions, how long do you think that will last? We now have just under 10,000li (2,600 gallons) of tanks – 2 x 2,000 squat tanks under our deck, a tall 4,500li tank beside the house, and a 1,100li slimline tank next to the carport. All connect to each other so that water is drawn off the lowest tank and the others empty to refill it. I wish we could fit in more. We’ve also made it easier to get tank water to our trees’ root zones.
4. I’ve converted as many hard surface areas as possible to permeable, so they let rain water infiltrate the ground instead of running off. We took up all the paving, except around the swimming pool, and replaced it with stabilised gravel pavement paths which let all the rain water soak through into the ground, keeping our essential claret ash shade tree well-watered.
5. Selected drought-hardy flowering perennials and a few annuals fill spaces between shrubs.
Through lots of experimentation (and wasted money) I have whittled down my flowering perennials to ones that can cope with with long dry spells but also high humidity, such as flowering aloes; Strelitzia (bird of paradise); daisies like Arctotis, Osteospermum and Gaillardia; Iris germanica; Gymea lily, dianella, tall kangaroo paws, and plectranthus and begonia cultivars in shade. Orange cosmos, which could survive a nuclear holocaust, thrives and self-seeds (but not in a crazy way) all-year round.
6. I’ve planted more succulents
I used to think that succulents were a) ugly, and b) going to rot into mush during long rainy periods. I’ve now decided that there’s many I like for both their foliage and flowers, and also lots that cope really well with high humidity, such as Kalanchoe, Sedum, Crassula, Senecio, Haworthia, Carpobrotus, Cotyledon, Aeonium, and Echeveria. These are especially good in pots on my sunny back deck.
7. Foliage plants for when flowers fail
When it’s too dry and windy for flowers to look good, I’ve added in foliage plants, including many succulents which look good all year round. Philodendron ‘Xanadu’ is an amazing plant which copes with both full sun and shade in Sydney and always looks lush and green; variegated Ophiopogon; Lomandra ‘Tanika’ and ‘Lime Tuff’; blue fescue; Helichrysum petiolare (especially its dwarf form), lemon grass; Cordyline cultivars; and reliable Alcantarea and Agave attenuata.
My garden is definitely NOT 100% drought proof. I still have plants that I love that I’ll need to keep better watered as the El Niño deepens, like purple-leafed Strobilanthes dyerianus, Iresine, my dahlia collection and some coleus (Solenostemon) cultivars. Even pineapple sage isn’t as drought proof as I’d hoped. But I think I’ve made it a whole lot easier to manage, without sacrificing lovely form, flowers and greenery.
** See the current Australian Bureau of Meteorology ENSO Wrap Up