In Australia, we’re fortunate enough to have an array of beautiful flora and fauna but unfortunately for some, this also comes with a host of uncomfortable allergies. According to Asthma Australia, plants that are blown in the wind such as grasses, weeds and certain trees are the biggest culprits when it comes to allergies and asthma in the garden.
On their website, Associate Professor in the School of BioSciences at the University of Melbourne, ProfessorEd Newbigin says, “Plants that have non-obvious flowers, called cryptic flowers, they are [typically] the ones to avoid. Birch is a good example. You may not notice the flowers at the time, but they release a lot of pollen into the air when they are flowering.”
This type of pollen is light and can travel long distances depending on the wind conditions and other factors. The Parliament of Australia’s National Health Survey suggests 4.6 million Australians (about 20 per cent of the population) are affected by allergic rhinitis.
What causes allergies?
Pollen is the main cause of hay fever or seasonal allergic rhinitis. Flowering plants produce small amounts of pollen which birds, bees and other insects can spread. The grass also produces pollen and blows in the wind, so it can impact people far away who can’t even see the plant itself.
“The true cause of our allergies is mostly from wind-pollinated grasses and trees, and the one that may be causing your head to feel like it is going to explode may be thousands of kilometres away from your home,” explained Jimmy Turner, the former director of horticulture at the Royal Botanic Garden Sydney.
Imported plants and grasses are the biggest cause of allergies.
Allergy symptoms
Common hay fever allergy symptoms include:
- Red, itchy eyes
- Coughing and wheezing
- Sneezing
- Hives or a rash
- Runny nose
- Asthma flare-up
How to avoid a flare-up
Whilst there are no real simple natural cures, you can change a couple of practices:
- Avoid going outdoors in windy conditions and keep up to date on the pollen count in your area
- Avoid being outside when the grass is being mown
- Wear sunglasses and carry tissues
- Keep windows closed on windy days
- Use recirculating air in your car
- Remove allergy-triggering plants from your home
Here are some of our tips for beating hay fever naturally. If you have severe allergies, seek medical advice to help relieve your symptoms.
Which plants cause the most allergies in Australia?
We’ve compiled some of the worst plants and trees that will set things off in Australia.
1. Mango tree
One of Australia’s favourite fruits is, unfortunately, one of the worst culprits.
If growing a mango tree in your garden, it’s important to note it grows up to 10 meters or taller and is a popular trigger of allergies.
How does a mango tree produce pollen?
On mango trees, pollen is produced in little pollen sacs located at the end of the male flowers (stamen). They release the pollen, while female flowers have a small ovary at the base that develops into fruit.
Mango flowers are usually pollinated by self-pollination, which means it is pollinated by other flowers on the same tree, as well as cross-pollination.
It’s the pollen from mango trees that causes allergies and rashes.
2. Plane trees
Plane trees are a gorgeous, popular variety that can be found everywhere in Australia, often along the edges of suburban streets or in parks. Their leaf shape is distinct, particularly the most common London plane variety. They have red or yellow spikey-looking flowers in small round clusters. The red, female flowers grow from newer shoots while the yellow, male flowers grow on older branches towards the trunk.
How do plane trees cause allergies?
Often, those who get hay fever or allergy symptoms from plane trees blame it on pollen, when it’s actually more likely to be trichomes – the fine, spiky hairs cover the young leaves of plane trees during spring. This “fuzz” on their leaves and stems becomes airborne as the leaves mature to pollinate other trees, and this is what often causes allergies or an itchy rash.
3. Ryegrass
Ryegrass, also known as ray-grass, is a short-lived perennial, biennial or annual bunchgrass. It is native to Europe, but can survive anywhere in Australia. Commonly they are found in pastures, along the footpath, sand dunes or riverbeds.
How ryegrass creates pollen
Ryegrass is wind-pollinated and releases an abundance of pollen during the peak flowering season from spring to autumn. It is from the large number of grasses that cause allergic rhinitis (hay fever) and other respiratory allergies in humans, and is also one of the most common. It causes sneezing, nasal congestion, runny nose, watery eyes and an itchy throat and eyes.
If mowing sets off your allergies, ryegrass is a common culprit. But making the switch to Australian grass is a great option, as they are drought-tolerant, slow-growing and have less pollen.
4. Wall pellitory
Pellitory (Parietaria judaica) or asthma weed is one of the worst weeds for asthma sufferers. It flourishes in warm temperatures and you can find it growing everywhere from the cracks of pavement to rocks and abandoned lots. Councils vigilantly control its spread, but it is a huge task. It is common to the Mediterranean and along the west coast of Europe, and has been introduced into Australia.
How wall pellitory triggers allergies
It’s a bushy, wind-pollinated perennial weed. Wall pellitory has two extended flowering periods. Its pollen will appear at the beginning of spring and persist until autumn. The nasty pollen causes asthma, allergic conjunctivitis, and allergic rhinitis (hay fever). If the plant hairs cling to clothing, it can also cause skin irritation.
5. Bottlebrush
One of our national icons is, unfortunately, an allergy trigger. Bottlebrush (Callistemon) have ‘bottlebrush’ shape flower spies and are most common in the east and southeast of Australia. They love wet or damp conditions and often grow along creek beds or flood-prone areas. They flower in spring and summer and are made up of a number of individual flowers.
How bottlebrush triggers allergies
The pollen from these red brush-like flowers is easily blown in the wind. When they bloom, the petals open to reveal long, colourful stamens, and each is tipped with an anther bearing yellow pollen.
6. Australian pine
Australian pine, also known as Casuarina equisetifolia is a flowering plant native to Australia and can also be found in New Guinea, Southeast Asia and India. It is a tropical evergreen and can grow up to 150 feet tall. It looks like a soft, wispy pine and its ideal climate is in coastal regions. Both pine nuts and pine trees are common allergens.
How does Australian pine cause allergies?
Male pine cones produce a powdery pollen, and once it is released, it is carried by the air to another female pine cone on a different tree. Once this is successfully achieved, pollination occurs. Pine pollination occurs in spring and can trigger the same people who are allergic to grass pollen.
7. Jasmine
This beautifully scented vine blooms in springtime, but as any allergy sufferers know, it is absolutely everywhere! They have strongly-scented flowers and are breathtaking to look at with the gorgeous, small flower heads decorating the leaves. They love moderate climates and a common variety is the night blooming jasmine.
How does Jasmine cause allergies?
While the flowers are in bloom, bees, butterflies, moths and other insects transfer pollen between them. Due to this process, pollen can be released, and often just smelling the scent from the plant has hay fever sufferers sneezing their heads off.
What plants make asthma worse?
Some shrubs and trees that may cause asthma symptoms are alder, ash, cypress and maple, to name but a few. Flowers in the asteraceae family including daisies, marigolds and chrysanthemums may also trigger symptoms.
