What to do with your plants after a heatwave?

Adelaide is now officially the hottest capital city in Australia after a 46.6 deg celsius day this week.  What does it mean for the plants in your garden?  And how do you help your garden recover from successive days of heat and sunshine?

There's no doubt that the best way to help your garden through summer is to prepare your garden before hand.  You can do this by: 

  • make it a practice to continually add organic matter to your soil by applying composts or well rotten manures regularly
  • Mulch to a depth of about 3cm each spring, and reapply as needed over summer.  Mulch insulates the soil and assists in preventing heat damage to roots.  Mulch is especially important for plants with a shallow root system.    Try Neutrog's Who Flung Dung, it's a mulch new to the market, and jam packed full of microbes beneficial for th soil and plant health.  
  • Apply Seasol each fortnight in the lead up to hot spells.  Seasol strengthens cell walls of leaves and stems, and assists with root development and overall plant health (it is not to be confused with a fertiliser).  
  • Apply Droughtshield to plants prior to a heatwave.  Be sure to read the instructions and don't be tempted to apply too regularly (an application should last about 8 weeks under normal growing conditions).  Droughtshield acts in a similar way to sunscreen, and is an excellent tool to prevent sunburn, heat damage and wind damage (it's also useful for transplant shock).  Droughtshield is an inexpensive way to help your plants cope better with the heat.
  • Use soil wetters.  Both liquid and granular soil wetters are excellent at helping to retain moisture where it's needed in the soil.  They are both easy to apply (liquid soil wetters come as either a hose-on, or you can mix in a watering can or bucket and apply that way, with granular soil wetters applied by hand across the garden).    Soil wetters can generally be reapplied every 8 weeks as needed during summer spells, and can be used in garden beds and in pots.  
  • Provide shade for particularly sensitive plants such as camellias and hydrangeas, and newly planted gardens.  50% white shade cloth is perfect for allowing enough light through, while giving protection from the worst of the sun's rays.    Temporary shade using beach umbrellas also does the trick.
  • Water well before days of extreme heat.  
  • During heatwaves do remember to leave bowls of water out for the birds, insects and lizards who live in your garden.  


So what do you do after an exceptionally hot day, or period of hot days, when you find burnt and shriveled leaves, and your garden is beginning to resemble the desert?   

  • Water.  Water.  Water.  The best way to help your plants recover is to water deeply as soon as you are able.  If you have a sprinkler use it, and allow it to gently soak into your garden.  For large trees leave a hose dripping on the tree for a day or so.
  • Don't be tempted to remove damaged and burnt leaves.  While they look unsightly, they actually provide protection to the leaves below them.  Once the seasons begin to change and the days really do cool down you can remove the sun damaged leaves.
  • If you haven't already, get busy applying mulch,  soil wetters, Seasol and Droughtshield, Do it now.  With more hot weather expected next week these steps will better help your already stressed plants cope with what's to come.
  • Don't be tempted to try and fertilise your plants into good health.  Your aim should be to gently strengthen the plant through fortnightly applications of Seasol until you notice the plant 'picking up'.   It would then be appropriate to fertilise if needed.  
  • Be sure to take a note of the plants in your neighbourhood, and in your garden, which have coped well with the heat, and those that have suffered.  Next time you're planting out a new patch be mindful of our hot Adelaide summers and be sure to choose a plant which will cope well with our harsh weather.  
  • Finally our garden staff have a wealth of knowledge.  They will be happy to help you reduce heat damage in your garden.