Recovering From The Heat

By Dennis Ting – Gardenworld Nursery

 

The record temperatures experienced in Melbourne for four days last week have certainly taken their toll on the gardens which are already suffering from the effects of drought together with limited watering due to current restrictions.

 

On the Saturday it had cooled down and I fielded numerous inquiries from customers who both visited and phoned us at Gardenworld.

 

The first question was usually along the lines of the plants were kept well watered at the roots but still got burnt.  The answer to this one is that with an ambient temperature of 45c and low humidity the atmosphere is acting like a dryer so no amount of water is going to help.

 

Taking a look around my garden and neighbourhood the damage done is still showing itself days after the event with lots of new dropped leaves under my plants.  So what is showing the most damage?  The usual suspects from cooler moister climates including Azaleas, Camellias, Rhododendrons etc are looking pretty crisp.  Even the  pittosporums have dropped all their foliage on the last 30cm of the tips.  Natives appear to have only suffered limited sun burn on the foliage.

 

In the fruit tree department I was surprised to find that stone fruit held up well including plums, peaches, nectarines, cherries and almonds.  Pip fruit including apples and pears showed more leaf damage and drop.  Some growers lost 25% of apples that were burnt or stewed. Sub-tropicals like avocados, white sapote and macadamias just didn’t like the hot dry (used to hot and humid) weather.  Surprisingly the citrus only suffered limited leaf damage and the loss of some developing fruit.

While that is a review of what has happened what should the next steps be?

 

Some customers have said that they wanted to go out and cut everything that is looking dead off. 

 

My opinion is that this is not a good idea as it will expose the inner leaves and branches which are likely to get sunburnt in the next heat wave or encourage fresh new growth that could be subject to sunburn too.  Also sometimes the stems may appear dead but buds may sprout from these as they may not be too damaged.

 

My advice is to leave the browned off leaves to provide protection to the leaves and growth below and only prune it off later towards the end of March once the risk of high temperatures has passed.  There would still be sufficient time for any new growth that arose to harden off before winter

Note from James: excessive high in nitrogen feeding would not be wise while there is a chance of  more hot weather. The new growth would be soft and tender and highly susceptible. We are recommending the use of Seasol as it does reduce the symptoms of stress from excessive heat. Keep mulching, and the use of wetting agents such as Saturaid will help reduce water runoff.

 
 

Comments

[Kate Page]

Thanks James - I was about to rune the dead and desicated leaves off my heat affected plants - now I will leave them till the weather is better. Much appreciated. K