Learn more about pollen - Birch

Birch (Species, Betula sp.; Family, Fagaceae)

The main species planted across Canberra in gardens and parklands is the Silver Birch (Betula pendula), which is a medium-sized deciduous tree, typically growing up to 25 metres high. It is noted for its slender trunk, white bark, and beautiful yellow leaves in autumn. Its flowers are drooping catkins, which produce large amounts of wind-blow pollen between August and October.

In northern latitudes, birch is considered to be the most common allergenic tree pollen, with an estimated 15–20% of people with hay fever sensitive to birch pollen grains. Cross-reactivity between birch and certain foods is also a common phenomenon. People with birch pollen allergies may react to kiwi, apples, pears, peaches, plums, coriander, fennel, parsley, celery, cherries, carrots, hazelnuts and almonds.

Distribution of Birch (Atlas of Living Australia occurrence map)

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Learn more about pollen - Privet

Privet (Species, Ligustrum lucidum; Family Oleaceae)

Privet or Ligustrum lucidum is the third member of the Oleaceae family that is associated with strong allergic reactions to pollen in some people. Privet is a shrub or tree usually growing 4 to 12 m tall and is evergreen. The flowers are wind-pollinated and are generally producing pollen from August to October.

Privet was widely planted in gardens, and was popular as a hedgerow in the early days of Canberra. Despite being removed from many gardens today it can be found as a weedy species especially in moist places and along river corridors around Canberra. 

Distribution of Privet (Atlas of Living Australia occurrence map)

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Learn more about pollen - Olive trees

Olive tree (Species, Olea europaea; Family, Oleaceae)

The Olive tree is a dense-crowned tree introduced into Australia for horticulture in the mid 19th century. In recent decades, some varieties have become aggressive woody weeds and can be found growing outside the confines of managed olive groves. The flowers are wind-pollinated and are generally producing pollen from August to October.

 

Olive trees belong to the same family as the Ash tree (Oleaceae) and it has been shown that people who are allergic to Olive trees also show an allergic response to Ash pollen (cross-reactivity).

Distribution of Olive trees (Atlas of Living Australia occurence map)

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