Hot Gardens newsletter about Australian plants and trees for U.S. gardens

Hot Gardens Newsletter: January

Australian plants for arid gardens

Australian acacia in bloom — This acacia is in bloom in the colors of Australia: yellow and green.

Really Southern Gardens. While it is definitely winter here in the northern latitudes, summer heat spreads across the land down under – the home of the acacia, eucalyptus, kangaroo paw, paper bark tree, and other Australian natives that do well in dry, hot desert climates. Consider some of these for your garden when Springtime planting arrives. An especially nice feature is that all of these are pretty much “plant and ignore” plants. Not much maintenance is required.

Weed or Beautiful Exotic?

A little water and lots of sun – that’s what the Acacia family of trees and shrubs need. One little known feature of Acacias is that they fix nitrogen in the soil — making poor soil better. Another fact: the Australian national colors come from the green and yellow of the acacia and the Acacia pycnantha, also called the Golden Wattle, is the national flower of Australia. Of the over 900 acacias in Australia, only 2 are readily found in our American Southwest nurseries.

Acacia baileyana (known commonly in Australia as the Cootamundra wattle) is classified as a weed by Australian plant societies, although many Australians enthusiastically plant it in their gardens. Here in the U.S. Southwest, however, this fast-growing multi-trunk tree or shrub is among the earliest bloomers, bringing bright, clear yellow flowers to the garden in mid-winter – probably a genetic memory of summer blooming in the Southern Hemisphere. And the blooms are fragrant, too.

Acacia redolens, with puffy yellow ball-like flowers, makes a great shrub groundcover for slopes with poor soil, spreading to 12 feet wide with little need for water.

Eucalyptus –the Dr. Seuss Tree

If you want shade and want it fast, plant a Eucalyptus tree – a tree illustrated in many Dr. Seuss books. Not only do eucalyptus trees grow rapidly, they need very little water and almost no fertilizer, except for an occasional dose of chelated iron, such as Kerex. Of the 150 species grown in the West, here are three that thrive in the desert.

Coral Gum (Eucalyptus torquata) grows to 35 feet, has light green to yellow-green leaves and flowers that look like Oriental lanterns. It is long blooming.

Cider Gum (Eucalyptus gunnii) adds height quickly to as much as 70 ft. and is quite hardy. It has long, silvery-blue leaves with green and tan bark.

Silver Dollar tree (Eucalyptus cinerea) is the source of leaves used in floral arrangements, but you have to keep cutting it back to get those round silver leaves. As the leaves mature they become long, narrow and green. Grows to 30 to 70 ft. tall – but not if you keep trimming it back!

Natural Companions

Near a Eucalyptus, consider planting a perennial Kangaroo Paw (Anigozanthos “Bush Gem”) which grows naturally in the Eucalyptus forests of Australia. As an accent plant, they start by looking something like a thin-leafed yucca–sorta boring–then spikes shoot up 2 feet or more above the leaves bearing bright tubular flowers at the top in yellow, red, purple, even green! The flowers are shaped like Kangaroo paws – hence the name – and are a favorite of hummingbirds. The ‘Bush Gold’ and ‘Bush Ranger’ hybrids are the easiest to grow and most resistant to pests and diseases.

Echoes of the East Coast. For those of you originally from the Eastern part of the U.S., the Australian Paper Bark tree (Melaleuca quinquenervia) can be a reminder of the white bark birch trees. The trunk is covered with a thick, light brown (almost white), perpetually peeling bark; the branches are weeping; the leaves are long and pale green. These look great planted as a small grove and need little water. A frost turns the leaves purple. A tip: peel the thick bark and use it to line hanging wire flower baskets.

And a personal favorite: Pink Perth

Callistemon Perth Pink bottlebrush The Perth Pink bottle brush (Callistemon), shown left, with its hot pink blooms is an eye-catcher that will thrive in a xeriscape garden. It can be hard to find, but worth it!

The Freeway Shrub. No, we’re not talking about the indestructible Oleander which is planted along freeways for hundreds of miles in California, but another one that seems to thrive in adverse conditions along roads and highways. It’s the red bottle brush tree (Callistemon citrinus). The Australians can keep all of the red ones. In our opinion, it is an ugly plant that grows fast and blooms with those red bottlebrush-looking flowers for months on end. Its one virtue is that hummingbirds like it. On the other hand, the Perth Pink variety, in the photo, is absolutely gorgeous.

One last reminder: brisk winter winds can seriously dehydrate plants so be sure to water them periodically over the winter even if the weather stays chilly.

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