Heat can take its toll on plants as well as people. By recognising the early signs of heat damage and taking some preventative measures, gardeners can help plants survive the rising temperatures without drying out completely.
Recognise the early signs of heat stress
High temperatures can lead to moisture loss in both plant and soil which can result in the following effects:
- Yellowing leaves. In the very early stages of heat damage, the leaves can begin to dry up and turn yellow.
- Crunchy or browning leaves. Look out for this, especially around the edges.
- Wilting foliage and leaves. Plants will have drooping foliage and wilting leaves even in the earliest stages.
- Dropping leaves. In severe heat, shrubs and trees might try to slow the loss of water by dropping leaves completely.
Choose plants less susceptible to heat damage
Many gardens have ‘heat traps’ – certain sunny, sheltered areas where heat is retained – in particular, walls can block out cooling winds so the soil at the wall base tends to be very dry.
Some plants are less susceptible to heat damage than others, requiring much less water to thrive. Here’s our list of the right plants for sunnier conditions:
- Campsis radicans
- Water early in the morning, paying special attention to young plants, as afternoon sunlight can evaporate the water.
- Wet the greenhouse floor in very hot weather to increase the humidity and reduce the temperature.
- Make sure water is actually being absorbed into the soil by watering the soil until run-off is noticed, immediately turning off your sprinkler or hose, waiting at least 15 minutes and watering again.
- Consider whether you can shade your plants with vines or pergolas and keep exposed lawn to a minimum.
- To prevent wilting in young plants, use an inverted flower pot to protect them from the sun.
- In areas where there are hot and drying winds, consider whether you can plant a row of trees or shrubs to act as a windbreak.
Tips for preventing heat damage
1. Be water smart
2. Add organic matter to retain moisture
Mulch the soil on a regular basis and after watering to preserve moisture and hold the water for longer. A thick layer (use a minimum of just under 8 centimetres) of organic matter will prevent the ground from drying out and also helps to manage soil temperature.
3. Shield with shade