The secrets of this year's wildflower season
Kevin Thiele, the curator of the Western Australian Herbarium, tells Australian Geographic of the ups and downs of this year’s wildflower season: where to go, what to look for and what’s impacting the season.
UNFORTUNATELY, EARLY INDICATIONS demonstrate that there is likely to be a poor wildflower season in much of south-west Western Australia this spring. While there were quite good rains in many areas over summer, autumn has been dry, and the forecast is for a warm, dry winter in the south-west.
The spring annuals, such as paper daisies, that form carpets of wildflowers depend on winter rains, in the same way as wheat farmers. If the rains fail, are poor, or are late, annual wildflowers either fail to germinate, or germinate late and grow poorly, resulting in poor floral displays.
Perennials are usually more resilient, and of course there are always extraordinary flowering shrubs somewhere in WA no matter how grim the season, but the massed displays are unlikely this year.
Probably the only area that’s doing well is the Pilbara, which after a late cyclone is starting to come into flower now. Again, without winter rains, it’s likely that spring in the Pilbara will be fairly dry.
There are two very different wildflower experiences in WA. The experience many people think about and see on the tours, is the massed flowering of annuals (paper daisies, pink velleia, parakeelyas) in the Murchison, Gascoyne and Goldfields after good winter rains.
The other experience is the flowering of shrubs in the Kwongan (Heathlands) both north and south of Perth, and in the banksia woodlands close to Perth.
This experience in some ways is less a spectacle and more a wonder – the Kwongan is one of the most diverse and rich vegetation communities anywhere on earth, and the plants in it such as banksias and their relatives, flowering peas and feather-flowers are some of the most remarkable.
By comparison, the massed flowering of the annuals and the semiarid regions is spectacular, but botanically is actually less interesting.
Personally, I get quickly bored when I drive through hundreds of kilometres of wildflowers of only a few species; but in the Kwongan, I often need to stop the car every 50 m or so because I’ve spotted something new and marvelous.
Note that while the massed annual flowering in the semiarid is shaping up to be disappointing this year, the flowering in the Kwongan and Mallee country along the south coast (Stirling Range, Fitzgerald River National Park) may be quite good, as there was summer rain that recharged the soil moisture, so even with a below-average winter.
Weather and temperature are the two main drivers. In desert regions, cold weather will delay wildflowers a lot, even if there’s reasonable rain.
A difficulty we have at the moment in in predicting the season is that there’s no normal any more. As predicted by global climate models, winters in the south are getting drier, but summers are getting wetter.
This season is a good example – quite good rain during summer, and then the season collapsed as soon as autumn started.
Wildflowers don’t know how to deal with this change, as it’s something they’ve perhaps never experienced before in their evolution (as a long-term trend).
It will be interesting to see how they cope. There will be winners and losers.
One fear we have is that in many areas in the Pilbara, the Gascoyne, Murchison and Goldfields, summer-growing buffel grass will be introduced. The grass is an environmental catastrophe that, once established, excludes pretty much all the native plants and changes the fire dynamics as well.
People should work their way around the south coast, perhaps also along the coast north of Perth, in places like Leseuer National Park and Kalbarri. Don’t expect to see spectacle, but get out of the car a lot and look for the flowering shrubs.
The richness and diversity of form of the flora of Western Australia is globally remarkable. Many of the species, especially in the Kwongan, are such survivors. They grow in some of the poorest, most nutrient-deficient soils on earth. They have to cope with regular droughts and raging summer bushfires, and yet (perhaps because of these challenges) they’re simply remarkable.