Summer coolers
Keep your garden thriving in the heat. Expert tips on summer mulching, pruning, and seaweed spray for a lush, resilient yard.
It is hot. You are hot. The neighbour’s dog is hot. will delight in the heat. The bushfire summer of 2019 gave us our first crop of dates: I’d assumed our climate was too cold for dates, though the foliage tolerates frosts. The bananas did wonderfully, as did the Kei apples, which are not really an apple, but a type of desert plum from the dryer parts of southern Africa. The skins are tough, but inside the flesh is sweet and luscious, even as the roses wilt.
Unless your garden is mostly sun-loving, it will need some help to look its best, or even just survive. The obvious solution is water. Water yourself, and the kids, as well as the garden, preferably at night and in mozzie-proof long sleeves and ankle protection. Yes, the clothes will get wet, but the wet clothes will cool you, as you water the roses. Watering at night means the soil stays damp longer.
Mulching helps keep moisture in and increases water penetration as worms and microflora incorporate the mulch into the soil, as well staying damper for longer. But use summer mulch — light, airy materials such as sugar cane slash or last year’s old corn stalks that will let the moisture from short rainfalls penetrate.
On the other hand, if you are on a steep slope or expect deluges, a dense mulch, such as decayed leaves or even compacted dry lawn clippings, will help stop soil washing away in heavy rain. Use your judgement and only use a dense mulch if you are sure it’s needed. Don’t use lawn clippings until they have dried out, as moist green ones can heat up. Never use lawn clippings for mulch in a drought unless mixed with autumn leaves and weeds.
The next slightly drastic step is pruning back your shrubs. This means they transpire less moisture on hot days. You may not get blooms for a month or two, but a mid-summer pruning means a magnificent blooming autumn. The exception is any shrub that only blooms once a year — prune it just after flowering, or you may not get any display until next year.
Almost any plant that wilts can be summer pruned, including citrus. All citrus are shallow rooted and easily die in the heat unless watered. A good pruning can help. Don’t assume native shrubs don’t need watering. Most natives have a sensible response when it’s too hot and dry: they flower, produced seed, then die, so their seedlings germinate when the weather is kinder. Prune them, water and mulch.
Just like small kids and the elderly can lose their appetites when it’s hot, plants can stop taking in enough tucker from their roots, especially if the soil is often dry. Give them a weekly dose of foliar seaweed spray, spraying under and over the leaves — preferably not just before a mid-summer thunderstorm. The seaweed spray will feed the plants through the leaves, as well as possibly thickening the outside of the leaf so they lose less moisture. A friend’s hobby is buying cheap, almost deceased potted plants from the local supermarket and coaxing them back to luxurious health. Her secret is seaweed spray, applied regularly and lavishly. She hasn’t had a failure yet.
Vegie gardens need tender care in summer, especially if you’ll be away for a few days. Try covering the bed with shade cloth, to both keep the soil cooler and to stop moisture evaporating. Well-fastened shade cloth will also protect your vegetables from hailstorms. If you have time, you can even race out when the sky looks like a purple and green-bruised knee, and hail seems inevitable, and drive tomato stakes firmly into the soil around flower beds or even fruit trees, then toe the shade cloth, or even a tarpaulin or old sheet or blanket onto the stakes. It won’t prevent damage, but it should limit the devastation.
Summer storms are also the reason to look closely at any big trees around your house, especially ones heavy with leaves. They may look okay now but remember that one litre of water weighs a kilo. How many kilos of water will that branch be carrying when it’s wet? When in doubt, call the tree doctor to have overhanging branches pruned away. A well-pruned tree will also be less likely to fall over in storm.
But the most important summer job of all is to find a comfy chair, a patch of shade, a large glass of something cool and think about your house and garden. What windows, doors or walls are getting the full force of the sun’s rays? Can you plant a deciduous tree there to shade your home in summer and let it warm up when the leaves fall in winter? The tree can’t be too close to the house, or it may damage foundations or pipes and fill the gutters with leaves, nor does it need to be close. Think how tall your chosen tree will grow: that will be the length of its shade when it’s full-grown. A good shade tree can be at least 3m or more from your house.
Consider pruning shade trees, too. Taking off the lower branches not only makes mowing under the tree easier but it lets cool breezes flow through your garden. Just make sure that the tree isn’t too top-heavy, making it unstable when wet.
And now continue to dream. No blooms yet? Plan your annuals to plant next spring, so next summer with be flower-filled.
