It has always been a challenge for gardeners and home owners to care for trees during Australia’s summer. Now, with periods of extended heat, it becomes most important to monitor your trees’ health and take steps to ensure their survival.
We’ve put together a guide to help you care for your trees during these hot and dry periods.
Knowing if a tree is drought-stressed
How do you know if your tree is suffering? Leaves lose their shine and change colour, wilting and curling up at the edges. They might go yellow or be smaller than usual, dropping prematurely, or turning brown and staying on the tree. Sometimes we mistake this for ‘Autumn coming early’.
A tree might appear to be surviving drought stress, but an extended dry period sets trees up for secondary insect and disease infestation. Check for signs of an insect attack, like the insects themselves and holes in leaves.
Sometimes, even though your tree is still alive, it’s struggling in the heat. Removing the struggling tree to plant a more suitable one may be the best option. Your arborist can help you remove it and give great tips on trees better suited to your yard’s micro-climate. Canberra has its own unique climate and environment challenges so you need to know your local conditions.
Caring for trees in heat
It’s easier for established trees to withstand drought, but most trees can use a little help in very hot, dry times.
It’s important to eliminate anything which might further stress the tree including ivy, mistletoe and creepers. Clear an area around the base of the tree and avoid fertilizers.
When it comes to watering, methods which apply water slowly, directly and at soil level are best. Sprinklers tend to soak the top soil only and can waste water.
Soaker hoses are an effective and efficient way to water trees – being porous, they release water slowly. Create a dripline of soaker hose in a circle around the tree, and allow it to run for a minimum of one hour at a time. The water needs to penetrate down to at least six inches.
Trees prefer a good, deep soaking about once a week rather than superficial watering every other day. Shallow watering encourages roots to stay near the surface, whereas deep watering encourages strong, embedded, drought-resistant tree roots.
Your arborist will be happy to supply more detail on use of soaker hoses and irrigation systems specific to your trees.
In addition to keeping the water up, it’s important to know that different tree species have different transpiration rates and react differently to drought stress. Australian trees are amongst the best at controlling water loss through their leaves during periods of low rainfall whilst maintaining fast growth rates. Species that have evolved in environments with more consistent and reliable rainfall patterns are not as well equipped to handle our hot dry weather and can be severely affected by drought stress.
Tips for planting and maintaining new trees
While some trees are far better suited to hot conditions than others, remember that no tree is truly drought resistant.
Any newly planted tree is more sensitive to soil conditions, and will require additional care through its first two years of life.
Here are some useful tips for looking after newly planted trees in hot, dry conditions.
- Water every two or three days for the first month until established.
- Water early in the morning or late in the evening to prevent evaporation from strong sun.
- A deeper soaking less often is preferable to lots of light, superficial waterings.
- Beware of over-watering in clay soils, as the clay can trap moisture and rot the roots.
It’s vital to get the advice of a good, local arborist who can guide you in the choice of trees ideal for the location you live in. They know soil, moisture and climatic conditions inside out, so don’t be afraid to ask for expert help. Our aborists in Canberra can help you make sure you plant the right trees and look after them properly in the dry.