Australia is one of the driest continents on the planet and yet we Aussies can be cavalier about how we use our precious water.
Do you remember Nana’s garden? A scratchy buffalo lawn, some geraniums and conifers; perhaps a vegie patch featuring iceberg lettuce and of course, the iconic Hills Hoist clothesline?
Perhaps you also can remember, as a kid, frolicking under the sprinkler for hours as the mercury rose along with the water meter? Such fun!
We’ve come a long way since then with our awareness of how to conserve water. Back then, everyone ‘did’ their own gardens and garden designers hadn’t even been invented yet. My, how things have changed!
There is a lot we can do as gardeners to conserve this dwindling resource.
WHERE TO START?
These days, we have water restrictions, pest apps, rain sensors, xeriscapes, wicking beds, pollinating drones and greywater systems – it can all be a bit overwhelming.
A good place to start when designing a dry tolerant garden, is with a basic site evaluation and how it will fit in with your lifestyle. Some questions to consider are:
How will the garden be used? How much space will be devoted to plants?
Consider the best areas for seats around the garden. This can increase enjoyment of the garden.
How much time to you have to spend on maintenance?
Do you want to attract wildlife/birds? Have a birdbath? Do you have a cat?
Is it windy? Wind dries plants out quickly and you may need to consider a windbreak.
Do you need some shade trees?
How about food plants? Athough edibles are not considered to be water-wise, according to a study done by Permaculture co-founder, David Holmgren; home gardeners can use as little as one fifth of the water compared to commercial growers per $ value of produce. Vegetable wicking beds are definitely worth investigating.
Consider hydro-zoning your garden. This simply means grouping plants with similar needs together ie – don’t put succulents and vegies together or acid loving plants with alkaline ones.
Think about what style of garden you prefer.
In Mediterranean climates, the ideal time to plant is in autumn, which gives a good six to nine months before the scorch of summer.
Native plants are the obvious choice for a beautiful water-wise garden. An attractive and biodiverse native landscape is indeed possible without any irrigation. However, if you are living in a harsh and hot climate with no summer rain, the plants will likely need additional water even once established unless you are using endemic natives which have come from your local area.
Like succulents, many natives can survive on rainfall alone but it depends on their origin. For example, if you are gardening on alkaline sandy soil in an exposed area with no trees, expect some plant losses, even with local native plants. It is a tough gig surviving these conditions. For those who prefer more choice than just local native species, some irrigation is recommended.
Blended native/Mediterranean plantscapes are becoming increasingly popular where plants of similar needs are artfully layered to complement each other, giving year round texture colour and interest.
Succulents and local coastal native gardens win the prize for the most water-wise styles. Succulents also have flowers which attract native birds. Design wise, their popularity is soaring because the forms are so varied, they are easy to maintain and virtually bullet-proof. They are also ideal to plant for under tree plantings where there is little soil space due to root competition.
Dry tropical gardens are also an option. Consider using frangipanis, ponytails, bougainvillea, agaves, crinum lilies, ZZ plant, philodendrons, hoyas, and aloe trees.
Trees are critical in a water-wise design, providing shade and lowering temperature by up to 10C on a hot day. In hot climates, plant deciduous trees to the north, east and west of the house to protect against scorching summer sun. Even native plants often appreciate some shade from an open canopied tree.
Under-plantings include: clivias, rock lilies (Arthropodium spp), dianellas, lomandras, correas, ground covers like Hemiandra pungens, Hibbertia scandens, grevillea Gingin gem, Acacia saligna Springtime Cascade, Atriplex spp., succulents.
Soil preparation is critical for a successful garden, regardless of style. Local native gardens are an exception but even indigenous plants grow better if the soil is improved a little.
The old saying, spend $1 on the plant and $10 on the soil may be an exaggeration but it is a good one to keep in mind. Soil preparation for clay includes incorporating organic matter (compost, soil conditioner) with gypsum.
In sandy soils, mix powdered clay with the compost when preparing the planting hole. Always mix any amendments thoroughly throughout the soil at a depth of 30-35cm.
Biochar is the ‘new’ soil amending kid on the block. It retains water and nutrients, supports microbial life and increases plant vigour while improving soil wettability and increasing drainage in clay. The extra health of plants and growth can be notable. www.charliecharcoal.com.au
After planting, protect plants and soil with a 5-6cm layer of chunky tree pruning mulch. Councils often offer this to residents for free or buy from a tree surgeon. Avoid peat/karri mulch, as being fine it tends to absorb water itself without allowing it to penetrate the soil.
WHAT IS A WATER WISE PLANT?
Water-wise plants are capable of surviving long periods without water. This only applies to succulents or established plants with deep rooted systems. If you are unsure if a plant is dry tolerant, observe the leaves. If they are small, needle-like, succulent, leathery, furry, silver or grey, it’s likely to be dry tolerant. Ditto if the roots are fleshy or have water storing nodules on the roots like clivias, daylilies, agapanthus and liriope.
Interestingly, established camellias are incredibly dry tolerant but people may not plant them because they think they guzzle water. Ironically, kangaroo paw cultivars can be water demanding in sandy soils. Cultivars bred to flower year round, need food and water to do this. In nature, they are considered annuals.
Be aware that the same water-wise plant in sandy soil may behave entirely differently in clay. This is why we can’t really trust plant labels.
A good horticulturalist at your local garden centre is worth their weight in gold.
GREY WATER – A CONSIDERED CHOICE.
Plants which can cope with brief periods of flooding are ideal for greywater gardens. They must also be tolerant of excess phosphorus, alkalinity and salinity. Fats in the water can make the soil hydrophobic, therefore plants also need to be drought tolerant. It’s a big ask.
Suitable greywater plants include: couch and buffalo lawns, fruit trees (drainage must still be adequate); callistemons, melaleucas, westringias, kangaroo paws, sedges and many grasses.
Being realistic about the sacrifices you may have to make in the bathroom and laundry is the first step to a healthy grey water garden. Say goodbye to fancy hair shampoos and conditioners, chemical body washes, fabric softeners and hair dyes. Say hello to simple, natural products like castile soap and eco liquid detergents.
Ensure that your irrigation system has indexing valves to regularly add or switch over to ‘clean’ water via rain, mains or bore. This helps to flush out soap residue, maintaining the health of your soil. Turn it off when it rains.
In our last garden our 10m2 banana/mango patch was irrigated by shower water. One autumn, we harvested 380 bananas and 36 mangoes (first time fruiting). I suspect growth may have also been supplemented by the ‘wee in the shower fairy’ though this was never proven!
Many established fruit trees are never watered in backyards and survive just fine; with greywater they will fruit more.
It is indeed a wonderful resource but requires some thought.
How often are you away? Is the mains water set up to take over when you are? How many people are producing how much greywater? Rules apply.
In Perth, setbacks for the greywater pipes must be 300mm away from the paths, carports and boundary fences, 500mm from buildings and 1m from retaining walls.
We drink (filtered) water and use it to water pot plants, fill ponds and wicking beds. Unfortunately even a couple of 1500L tanks, will empty quickly during a hot dry spell if used for irrigation. Unless you have the space and budget for investing in large tanks; plumbing rainwater into the house for use in showers, laundry and toilets during the wet season is probably the best way to reduce your bills and save this precious resource.
MYTH – ALL VERTICAL GARDENS ARE WATER GUZZLERS
Vertical gardens have become very popular lately. If well-designed and located, they are water-wise. Our lush looking vertical garden receives morning sun and is watered every 1- 2 weeks in summer. Plants include bromeliads, anthuriums andTradescantia purpurea. Succulent vertical gardens are an even better choice.
Water-wise gardens can be attractive, biodiverse and beautiful. Visit your local garden centre or, if you don’t feel confident to DIY, engage an experienced garden designer to create a garden which will thrive in your local conditions.