Orchids are blooming early in the shade house at Cranbourne Royal Botanic Gardens this winter.
“We usually don’t see these warmer temperatures until early spring,” orchid conservationist Alex McLachlan said.
“This has brought about early flowering and early germination for a lot of our orchid seeds and flowers,” like the Caladenia valida orchid species, which is flowering two months early in the Victorian gardens.
Shade houses are often warmer than the wild, said Dr Noushka Reiter, a senior research scientist also from the Cranbourne Royal Botanic Gardens.
“So if you have a little bit of extra warmth outside, that is retained within the shade house and then it pushes those plants on a little bit further.”
A warmer winter is changing the way plants “normally act”, McLachlan said.
Temperatures have been fluctuating in “fits”, with warm waves followed by cold spells, “which can cause things to happen before they should”, said Dr Kara Youngentob, an ecology research fellow at Australian National University.
“You see examples all over the place,” she said. “Just walk out your front door. There’s no doubt about it. The climate is warming and as a result, nature is responding,” Youngentob said.
Magnolias – famously a sign of the start of spring – have been spotted in bloom around Victoria well before the end of winter. Early flowering jasmine and jacaranda plants have joined them.
In Canberra, stone-fruit trees growing nectarines and apricots have been blossoming out of season.
And conservationist Jerry Coleby-Williams has observed the same of early sprouting produce in Brisbane, which he shared to Facebook in a flurry of posts through the end of July.
His solanum pimpinellifolium tomato crops began fruiting “extra early”, his jackfruit tree is “producing spring fruit”, and his eggplants are growing at the best rate he has seen in almost 20 years of gardening – all of which he attributes to a warm, dry winter.
He shared another “big surprise” – voodoo lily in full bloom.
“Normally it responds to hot, dry spring weather and it attracts blowfly pollinators,” Coleby-Williams wrote in a post. “Despite ponging its heart out, so far no blowflies are answering its call.”
Though temperature is warming, light cycles are not changing. This can “throw things off”, Youngentob said.
A complex system of interreliance between plants and animals is responsible for cycles in nature, including where plants grow, what plants attract pollinators and the types of chemistry those plants need to protect themselves, Youngentob said.
This system has historically been in sync: “Animals are where they need to be to pollinate plants, plants get pollinated, and life continues.”
But when change hits the system quickly, cues begin to fall out of place, disrupting that life cycle.
Pollinators like honeybees and blowflies do not respond to the same temperature cues that plants do.
“You can have a mismatch, and that can cause a kind of ecological chaos,” Youngentob said.
She points to the relationship between bees, birds, wildflowers and trees. “Plants flower at very specific times, and those usually coincide with the movement of the key pollinators,” she said.
“But when you have early blooming, and it is still winter, you might have some of those pollinators like bees coming out … when they’re not as active because it is still too cold for them to effectively do their job.
“These relationships require kind of an orchestra, a concert of activities that need to happen together. If they don’t, then we lose the ecosystem services those relationships between plants and animals give us, and things start to fall apart.”
