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7 steps to create a cool haven

Summer 2018/2019 was Australia’s hottest summer on record and temperatures have risen by over 1 degree since records began in 1910. It’s likely most of Australia will be hotter and drier in the future.

Many Australian homes are poorly designed and don’t consider the local climate.

Wherever you live, there are many things you can do to create cool outdoor spaces that improve your health and well-being. Studies shows the more contact with nature, the better we feel. 

Whether you own a home or are renting, creating a cool haven adjacent to your place will keep you cooler on hot summer days and nights.

Large pots planted with drought hardy Crepe Myrtle and planted with groundcovers on Lonsdale St, Braddon.

Plants play a key role in keeping our gardens and homes cooler and viewing bright green leaves feels uplifting when the surrounding landscape is yellowed. Thermal imagery demonstrates trees can reduce surface temperatures by as much as 10 degrees.

Here’s 7 points to consider when creating a cool haven.

  1. Climate

    Find out more about your local climate – for example, Canberra has a climate of extremes – hot dry summers and cold winters. In Canberra, the emphasis should be on maximising summer shade and in winter maximising sun. Temperatures of -7C in winter are not unusual. This will influence the trees you grow – in most situations, deciduous trees will be most appropriate.
  2. Soil

    Assess the soil on your site. Is it clay, loam, rocky, mainly sand or other? Aim to amend existing soil not remove it. Ideally you want to turn your existing soil into a sponge that can absorb water and carbon – the best way to do this is to start composting your household’s food scraps. Once they are broken down you can incorporate them into the soil. If you are low on space, a bokashi bucket is small enough to fit into a kitchen and breaks down material with no odour.

    Add locally sourced organics like fallen leaves, coffee grounds (plenty of cafes bag these up each day) and manure. And use a thick mulch (75-100mm depth).
  3. Water

    Irrigation is critical to creating a lush outdoor space, however, check out the water restrictions in your local area. If you own your own home, consider installing rainwater tanks or building a grey-water treatment system.

    The most efficient way to irrigate is to use drip irrigation rather than sprinklers. Other options include the use of wicking beds or sub-surface irrigation using water harvesting. If you use grey water from the shower or washing machine, choose cleaning products that are safe for the garden and avoid splashing edible leaves with grey water as it can contain E.coli.

    Ponds can create a cooler feel and the sound of running or spraying water is soothing. For renters and apartment dwellers create a pond in a large pot with a number of wetland plants and gold fish. Including a pump will reduce the likelihood of mosquitos and algal build up. Gold fish provide splashes of colour and are a tough low-maintenance pet.

    Well-designed in ground ponds will provide habitat for frogs, dragonflies and birds will enjoy bathing in them in hot weather. Insects can drown in buckets of water or deep ponds so provide shallow saucers filled with water and gravel to give insects like bees and lady birds a drink.

    If you are creating a potted haven, think about how you will keep your plants watered in hot weather? Containerised plants dry out very quickly in hot weather and may require watering twice a day. Check if there is a tap handy. Using wicking or self-watering pots help ensure plants stay watered at their roots.
  4. Containers

    If your only option is to garden in containers follow these steps for a greater chance of creating a great outdoor space that you want to hang out in.

    Repurpose or buy the biggest container you can for growing shade trees. The minimum pot size for a tree that’s around 1.5 metres tall would be about a 40cm diameter. Think about the weight of the pot too, will you be able to move it around once it has soil in it?

    Buy quality potting mix and look for the Australian Standards tick of approval on the side. Use water holding crystals to trap moisture near the plants roots.

    Choose plants appropriate for your area and consider multiple functions of plants – if you are choosing a tree think about the following: will it provide shade in summer and allow sun through in winter, does it bare fruit and does it have flowers attractive to pollinators?

    Consider incorporating  a groundcover around the base of your tree. When the groundcover begins to wilt – investigate if the potting mix is dry. The best way to test this is with your finger.

    Mulch your plants – mulch reduces the amount of water evaporating from the pot. Make sure you move mulch aside to checkwater has penetrated below the mulch into the potting mix. 
  5. Plants

    Choose plants that can cope with a hotter, drier future. Check out climate model projections for your area. Climate modelling shows Canberra’s climate in the future will be more like Dubbo and Gilgandra – a 4.5 hour drive north of Canberra.

    Choose layers of plants – groundcovers, climbers, shrubs and trees – this will help create lots of evaporative cooling in the garden.

    In order to create a lush feel around your home –consider using some plants with large green leaves. These might be plants you can grow in your pond in sight of your living area.
  6. Seating

    Incorporate seating into your outdoor space – a place to unwind, sip on a favourite drink, observe wildlife and interact with those you share the house with. Leave your phone, ipad or laptop inside – this is time to unwind.

    Seats don’t need to be expensive – an upturned crate with a cushion can provides a great place to perch.
  7. Outdoor cooking

    One of the best ways to keep your home cooler on hot days is to cook outside. Alternatively, ditch the cooking and make a salad or a Buddha bowl.

Cooking outside on a hot night reduces temperatures in the home and reduces the need for using cooling. A small gas burner is used to stirfry outdoors.

Further reading

Climate Change in Australia – projections for NRM regions
The Canberra Garden – Using Water Wisely
The Canberra Garden – Choosing Plants
Gardening Australia – How to make a wicking bed

Community funds micro-forest

The Climate Factory and the Downer ParkCare group raised $20,000 to build a pilot micro-forest at the Cole St park in Downer. Over 180 individuals and businesses supported this initiative.

Edwina Robinson, Landscape Architect and Founder of The Climate Factory says, “planting trees is one of the simplest things we can do to address hotter, drier climates. Trees cool the environment, provide habitat, absorb carbon and improve property values.”

The $20,000 raised will pay for community engagement, development of a Landscape Sketch Plan, soil improvement, 1500 climate-ready native trees, shrubs and groundcovers and a water cart to keep plants watered during the establishment phase. The Downer ParkCare group will maintain the space and will have a say about other features they’d like to see in the park.

Robinson formed the social enterprise, The Climate Factory, in 2019 after Canberra experienced its hottest summer on record. She says, “Bureau of Meteorology records show January 2019 temperatures for Canberra were 6 degrees above average. I knew I needed to do something. So whenever I think, why the hell am I doing this, I remind myself I’m doing this for my adult children and my unborn grand-children”.

Robinson says she wouldn’t have had the confidence to launch her social enterprise and Crowd Funding campaign without the support of the Mill House GRIST program.

The Climate Factory will work with tree and native plant experts to create a climate-ready plant list for a public space. They will choose plants with low flammability and that can cope with hotter, drier weather.

Native plant nurseries will start growing plants before the end of the year with the first planting day scheduled for April 2020. Robinson says “hopefully it will be a mild Autumn and plants will get a great start”. Supporters who pledged $25 or more will be invited to the first planting day in 2020.

In October 2019, Robinson and Lachlan Richardson, Bluebell 2509 installed a micro-forest of 300 native plants across the road from the Cole St Park. They are looking forward to working with the Downer community to watch both micro-forests grow.

Land surface temperature February 2017. Some of the hottest places in Canberra are the new developments on the outskirts, like Gungahlin, Molonglo Valley and West Belconnen. Source: CSIRO

The Climate Factory is looking for partners and sponsors to build a micro-forest in a school in one of Canberra’s urban hot spots in 2020. Robinson says, “The Climate Factory will use land surface temperature maps created by CSIRO to help work out which Canberra schools need micro-forests the most. We will work with students and teachers so they can learn about the values of forests and together design and build a micro-forest and show them how to maintain it.”

Service One, a 100% community owned bank, kicked off the fundraising with $5000. The other official sponsors are:

Gold Sponsors $1000
Light House Architecture and Science
Federation Financial
Silver Sponsors $500
Bluebell 2509
Tim Smith
Bronze Sponsors $200
WECAN
TreeCreate
The Tree Man
Canberra Magic Kitchen
Robyn van Dyk
Katherine Horak
Bernadette Law
Alastair Crombie
Robbie Kruger
Baily Hepple
Maryanne McKay
Suzanne Moulis

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The Silver Birch is dead

In 2010, I bought a Canberra fixer-upper with no garden to speak of. The front garden boasted two non-fragrant roses, an oleander (despised from my childhood) and a Liquidamber street tree.

As a young Landscape Architect student I was besotted by Edna Walling. Acclaimed as Australia’s first landscape architect, Walling was an unconventional woman. She ran a landscape design and construction business from the 1920s , built her own cottage and created an English style housing development in Victoria, named ‘Bickleigh Vale’.

The first essay I penned at the University of Canberra was about Miss Walling’s design style. English born, she determined the location of Silver Birches by scattering potatoes on the ground.

 With a new garden to design and plant on a budget, I decided I wanted a grove of white trunked Silver Birch (Betula pendula). Underneath I would grow rosemary and Grevillea. Note: the rosemary (tough bugger that it is, thrived) but the Grevillea ‘Deua Flame’ died one by one.

Birches have a reputation for thirst – but the Millenium Drought was over and I knew I could gravity feed water from an upstairs bathroom, if needed.

That Autumn, after removing the roses and oleander and the patchy grass, I planted nine $20 birches into compost enriched soil. I wasn’t as flamboyant as my hero, Walling, the birches were planted in evenly spaced trios.

Three years and a few wet seasons later, the Birches thrived. Lying in my upstairs bedroom I could glimpse their canopies and marvel as the Rosellas performed acrobatic feeding acts dangling from drooping branches.

But success was short lived.

Those nestled close to the house or large shrubs thrived. However, the Birches abutting the western side of the block with its hard, hot drivewayof concrete and bitumen and nothing to buffer blasting summer winds, fared poorly. Their trunks were only half the diameter of the happy ones.

In the back garden, I planted three tubestock of Snow Gum (Eucalyptus pauciflora). They grew quickly to about four metres high, and after a couple of very dry summers I was left with one survivor. Snow Gums suffered a similar fate at the nearby Banksia St, O’Connor wetland where planting commenced in 2010.  

Records from the Bureau of Meteorology show that Canberra’s summer of 2018-2019 was the hottest on record. The Birches branches browned.

This year, nine years after planting, I removed three of them, and sold the house.

Temperatures in Australia have risen by at least 1 degrees celcius since 1910. And we know Canberra’s future will be hotter and drier with more extreme events, including heatwaves and intense rainfall.

Temperatures will not only impact the types of trees we can grow in Canberra in the future but our ability to stay fit and well.

Increasingly evidence shows high temperatures result in increases in violence and mental health presentations. And who wants to exercise when it’s extremely hot? This will no doubt impact obesity levels and associated preventable diseases, like diabetes.

Unfortunately we’ve lost a significant number of trees in Canberra over the past few years and it’s vital to boost our tree canopy with climate-ready species. Note: the ACT Government committed in the 2019 budget to plant 17,000 trees over the next four years.

As I cycled round Canberra in Autumn 2019, I noticed one stellar deciduous tree – the Crepe Myrtle (Lagerstroemia) with its motley bark, multi-trunked stems and vibrant flowers was a stand-out.

Another, under-celebrated tree, the Kurrajong (Brachyciton) has proven to be a great performer. At Banksia St wetland, young plants were attacked by cockatoos (the vandals of the bird world). Those that survived are robust and beautiful.

Leaves of the Kurrajong, at Banksia St, O’Connor wetland. The wetland was constructed by the ACT Government in 2009 and the surrounds planted by the community from 2010.

Creating climate-ready public spaces and gardens will help us thrive in a hotter, drier future. The ANU has been working with the ACT Government to develop a list of trees suitable for public spaces for changing conditions and CSIRO has developed heat maps to identify areas at most risk of heat exposure with vulnerable populations. There are sections of Belconnen, Gungahlin, Molonglo, Tuggeranong, Weston Creek and Woden where communities are at significant risk. No surprises, that if you live near Lake Burley Griffin you will probably be ok during heatwaves.

The CSIRO report recommends planting vegetation and forests in our public spaces, streets and parks as one of the main ways to mitigate future heat. Plants have a more significant cooling effect if we can find ways to irrigate them, using water harvesting.

As a result of the hottest, summer on record I knew I needed to act. So The Climate Factory, was borne.

The Climate Factory is a social enterprise, that designs and builds micro-forests, to ensure we thrive physically and mentally in a hotter, drier future.

Ground-covers cool the earth in micro-forests

When you think of a forest, the first thing that pops into your mind is probably trees. While trees are an essential part of a forest and do much of the heavy lifting others have a role to play. Think shrubs, climbers, ground-covers, orchids and epiphytes.

At The Climate Factory, we design, build and teach about micro-forests. We are inspired by the industrial engineer, Shubhendu Sharma who applied Toyota’s production systems to forest-making and now coordinates native forest plantings across the world. Sharma in turn, was influenced by the Japanese botanist and plant ecologist, Akira Miyawaki, author of ‘The healing power of forests’.

The Climate Factory’s smallest forest is the size of a car space – 5.5 metres x 2.5 metres . We’d love to see micro-forests replacing car spaces in urban areas as we transition away from private vehicle use to a more regenerative way of living.

If you look closely at a forest, you will notice plants jumbled together. They tend not be evenly spaced and plants compete with one another for light, nutrients and water. And plants are a range of different heights, some have just germinated, some have died and some are in their prime.

At the bottom of the forest are the ground-covers. They have a special role to play. They keep the ground cooler while your micro-forest is establishing and provide habitat for beetles, skinks and lizards. Eventually the forest will become too shady for many of them and leaf litter may take their place.

Starting at the forest floor, here’s our recommendations for four native groundcovers (two which are edible) that would be beneficial in a native micro-forest.

Hardenbergia violacea

A stand out is the tough Hardenbergia violacea, also known as False Sarsparilla. It occurs as an understorey plant in native forests either as either a groundcover or twines its way up shrubs. It’s in the pea family and bears purple flowers at the same time as Wattles signalling winter is almost kaput.

It has leathery dark green leaves and once established is drought and frost hardy.

Hardenbergia can be grown from pre-treated seed. We collect the dried pods from  a plant thriving in our Moruya garden. Soak seeds overnight in hot water and plant them in a mix of 50:50 coarse river sand to native potting mix. The seeds germinated indoors in a warm sunny spot from 10 days to three weeks.

Picture of freshly germinated Hardenbergia seeds.
Hardenbergia seeds collected from the garden germinate after pre-treatment with boiling water. We used a mix of washed river sand mixed with native potting mix to make the seed raising mix.

Myoporum parvifolium

This is a rapidly growing bright green groundcover that comes in a couple of forms – either fine leaf or broader leaf. It can become woody if not left in check as it grows. Creeping Boobialla, bears small white or pink flowers and creates a living mulch over the ground.

It self-propagates by laying down roots across it stem as it sprawls over the ground. These can be removed and repotted to create new plants.

In our west facing front garden in Moruya (which we are infill planting to turn into a micro-forest) Creeping Boobialla makes a fast green mat with Pigface (see below).

Carpobrotus glaucescens

Many will be familiar with the iridescent pink flowers of the Pigface from the sand dunes of the east coast of Australia. As a kid I thought it was a weed and was unaware the flowers form edible scarlet fruits, a snack for coastal indigenous people. The fruits surprise with their salty tang.

It’s a rapidly growing plant, with sage green succulent leaves, and pieces can be broken off and potted to create new plants. As it’s a succulent it’s best to let the end of the broken portion heal over first (for a couple of days) before growing in a free draining propagation mix.

Pigface is drought and cold hardy to a point. We experience -4C frosts on our block in Moruya, NSW  and it has withstood those. It’s been used on the green roof at Thor’s Hammer in Fyshwick, Canberra and has survived.

Tetragonia tetragonoides

This leafy green sprawling groundcover, also known as Warrigal greens, is edible and is rumoured to have helped Captain Cook’s crew stave off scurvy.  It grows wild near the beach and along rivers underneath Casuarina glauca and prefers a slightly more sheltered position and more water than Pigface.

Like many other leafy edibles, its leaves are high in oxalic acid and should be blanched prior to eating. In Canberra, its best grown in a sheltered position with adequate irrigation. The leaves will tell you if its thriving. It will have large green leaves if happy or small leaves if it’s struggling.

It can be grown from seed or by cuttings.

Edwina Robinson