Choosing plants and trees that will survive a warmer climate

Trees are the most important element in a garden. They are “the most prominent and the most permanent, the ones that set the scene and dictate the atmosphere.” - Hugh Johnson, author of The World Of Trees, 2010

But most of our created landscape is a ‘mishmash’ of struggling deciduous trees or untidy, straggly natives. Most deciduous trees introduced into Australia came from areas with wetter and cooler summers so that,
just as they move into leaf, the moisture runs out and
they lose foliage and retreat.

Whilst our natives have adapted to our hot, dry summers, many have an untidy habit, provide poor shade and drop branches and leaves that create litter for bushfires.

To create a beautiful landscape we must choose trees carefully, giving preference to evergreens that will grow through our warm winters (rainforest) or trees that come from hot, dry climates and have deep, water-seeking roots.

Tree planting has to be a rational, carefully planned process, but there are a surprising number of beautiful trees with tropical, green-looking foliage that thrive in areas with less than 500mm of rainfall.

White Sapote

Casimiroa edulis — Sadly this magnificent fruit never reaches the fruit markets, although it’s not for want of trying. Louis Glowinski, in his book The Complete Book of Fruit Growing in Australia, lists 12 different cultivars, which gives us some idea of how many nurseries have tried to commercialise this fruit.
Diggers listed this fruit many years ago and relied on the pollination of its flowers at Heronswood, which have failed recently, preventing us from listing it. However our friends at Tropical Fruit World, Duranbah, NSW have had success, so we can now offer it again.

From The Australian Fruit and Vegetable Garden:
‘The fruit is unaccountably rare … with the buttery texture of an avocado combined with the sweetness of a rich custard. It is the perfect fruit size – about the same as an orange and as easy to grow. It can self-pollinate but
fruit set is improved with good pollen partners.’

Even if you don’t get the pollination that you want, it makes a very elegant, small tree for the urban backyard.

Argentine Ombu

Phytolacca dioica — Ombu has a massive, swollen trunk which is a huge water storage vessel. It has the largest girth of any tree, reaching over 40 metres in circumference. The white flowers of this magnificent shade tree are a magnet for bees in spring. It is as practical as it is bizarre, growing rapidly in dry conditions and poor soil.

There are spectacular examples in our botanic gardens.
It is much easier to grow than those other pre-historic looking trees such as the African Baobab or the Australian Bottle Tree. Kate Bucknell from Queensland writes about her experience with Argentine Ombu: ‘It is 4.5m high after 18 months, and whilst a –5°C frost defoliated it temporarily, it thrives in the 45°C heat’

Japanese Raisin Tree

Hovenia dulcis — We procured this tree for our members in northern states because it needs more heat to flower and fruit than is available in Melbourne or Sydney. It grows as fast as a eucalypt and it’s the stem that you harvest, not the fruit or seed. Its raisin-like fruits will dry within the tree, so shake it for a winter snack.