A wattle in full golden bloom. But it’s not the culprit. Photo: Ian Fraser.
You’re looking around at those showy wattle flowers at the moment, seething from behind your itchy eyes and runny nose, aren’t you?
Yeah, you’ve got the wrong culprit.
Simon Haberle is the director of the Canberra Pollen Monitoring Centre at the Australian National University (ANU), and is predicting another above-average pollen season for Canberra and beyond – but it’s got nothing to do with today’s exploding blossom trees.
“This year is likely to be a strong one (above average) given the wet winter and prediction of a warm and wet spring from the BOM,” he says.
“We are sitting in or close to a La Niña-like climate system, which is a good predictor of a strong grass pollen season.”
Recent years of wet weather have led to more intense pollen seasons for Canberra, starting early in mid-September and running through to November and December. And while this year’s season might be off to a slower start due to a cold and wet winter, all the signs are pointing to another rotter.
“You’ll start to feel [the allergies] soon, because once it hits 19 to 20 degrees Celsius, the productivity for the grass and trees is really going to kick in,” Mr Haberle says.
“We’re already seeing it in the trees – the cypress pine and elm trees – and abundant pollen is appearing in our daily counts, so it’s a signal for an above-average season.”
It’s this fine yellow powder, combined with dust from rye grass – rather than the more obvious, heavier pollen put out by blossoms – that causes the most grief for hay fever and asthma sufferers.
Rye grass is to blame for Canberra’s extreme levels of pollen. Photo: Canberra Pollen.
“People think correlation equals causation because it looks bad, but that’s a misnomer,” Mr Haberle explains.
This is due to a scientific distinction in trees between those that rely on wind pollination (anemophily) and those that rely on insect or animal pollination (zoophily).
“Wind-pollinated plants, such as grass and some trees, produce abundant pollen that can be blown around for many kilometres. Insect or animal-pollinated plants like the wattles tend to have sticky or heavy pollen that doesn’t fly very far from the plant,” he says.
“Not head diving into a wattle tree might be strong advice, but if the pollen doesn’t get blown around too much and drops straight to the ground, you won’t have it causing big hay fever responses in the population.”
Elsewhere, particularly around the Riverina, the canola crops are about to turn the fields highlighter yellow. But even here, it’s the same story.
“Canola is an insect-pollinated plant, so the pollen doesn’t travel far, but if you are close to it on a windy day, it can cause an allergic reaction in some people,” he says.
From late September, it’s then the turn of the rye grass pollen for Canberra – another major source of misery.
Rye grass was introduced to the region in the early days of European settlement to improve land for sheep grazing, and is particularly prevalent in the north-western parts of the ACT.
“A lot of our storms and strong winds come from the northwest, so the pollen can be blown tens of kilometres across the city and generate hay fever and asthma in people a long way away.”
Simon Haberle at last year’s ANU ‘Pollen Immersia’ festival. Photo: James Coleman.
There’s more.
A variety of herbs and weeds are known to produce allergenic pollen, primarily in late spring to summer – chiefly Lamb’s Tongue, an abundant lawn weed.
And while you might blame the grass for making you suffer while mowing the lawn, Mr Haberle says it’s more likely ‘Alternaria’ – microscopic fungal spores or moulds common to plant leaves and stems and grasses, especially during dry spells.
Is there any escape? Yes, but not in Canberra – or Wagga Wagga and Wodonga, cities which also stand out on Australia’s allergen heatmap.
“A big population and a big diversity of allergenic trees and grasses just come together to make Canberra a hotspot.”
Mr Haberle will be presenting at the ANU’s annual ‘Pollen Immersia’ festival on Friday, 12 September, described as an opportunity to “hear from Australia’s top pollen experts, peek behind the scenes of daily pollen counting in Canberra, and find out how this tiny stuff can pack a punch for hay fever and asthma sufferers”.
Register on the ANU website (entry is free).
