Our garden is integral to our climate control at Ligaya Garden. It has grown in a way that the large trees shade both smaller plants as well as the house, and smaller plants shades the ground, to protect the soil.
These layers of natural protection are not perfect yet but as an example, in descending order of size and shade are, a Plum tree, a Cape Gooseberry, then a Sweet Potato.
The long axis of the garden is North -> South, and the Sun does the most damage from the West in the afternoon. There is plenty of heat in the backyard in the morning (40°c by 10 am some days) but that is fairly short lived compared to what hits the front. It has taken a few years to get the mix close to right and we are awaiting the results at the end of this Summer.
If you want a bit more information on keeping your garden going over Summer, check out our Gardening In The Heat page or Water Saving Approaches to Gardening.
One of the biggest problems that we have is a hot, dry, Northerly wind that comes, literally, straight off of the desert. We have experimented with different plants to block this but most take a beating, The exception has been Sweet Appleberry (Billardiera cymosa) which grows along the Northern fence and provides shelter for the garden and an annoying amount of Sparrows and provides fruit that is mostly eaten by Sparrows.
A passion fruit we’ve grown to climb up wire protects the front wall of the house, and the trees and plants by the front take the brunt of the wind and sun.
Plants As Air Conditioners
One of my favourite quotes (though I can’t remember where it came from) goes something like this; ‘every leaf is an air conditioner’.
Leaves work in the same way as evaporative air conditioners. Moisture is let out of the leaves (transpiration) and cools the air passing over it as it evaporates. A breeze through a tree is cooler and moister than a breeze over open ground.
In short, the more plants you have between you and the full hot Sun, the cooler the air will be.
Ground covers & Soil moisture
Keeping moisture in your soil and mulch help to reduce air temperatures close to the ground. A thick layer of mulch will help the soil retain moisture but unless water is added to it, will eventually dry out and actually repel water. Adequate shading is the best way to keep mulch and soil moist.
Living ground covers are better, and they can give you food too. Our favourites are Sweet Potatoes and Warrigal Greens.
As breezes move close to the ground, ground covers cool and humidify the air and pull it down to cool the soil as well.
The best way to keep something cool in Summer without great energy and water inputs is to block the direct sunlight from hitting it.
The tall trees in our garden shade a lot of things – each other, steel fences, smaller plants, the soil and, of course, the house.
Our Plum tree is the most important tree that we have. We have let it grow a bit beyond the size at which we could easily net and harvest but its protective function easily makes up for that. We let it grow to about 5 metres at which height, it shades most of the garden at some stage as the Sun makes its way across the sky and protects the front door and living room in the mid to late afternoon.
Over the past few years, we’ve tried growing vines to shelter parts of the garden and the house with mixed success. Our most successful was a Passionfruit that covered the bedrooms and the path in front of them. This got sick this year and died back too far to provide shade, so has been cut right back in the hopes that it will come back next year.
Different vines provide different amounts of protection. Apparently, Grape vines transpire the most water and so are the best air conditioners in that sense. They are lush and provide food too. One of their main benefits is that they are very, very hardy. As time passes, we will grow more grape vines near to the house and along fence lines.
Honeysuckle and Jasmine hug the wall near to the bedrooms. They are on wooden trellises and protect the house as well as spreading their beautiful perfumes. Two bonuses!