Temperature and rainfall
It is no surprise that the flowering period was delayed this year with September’s record rainfall reaching the fifth wettest month on record for Australia and over twice the national average in comparison to September 2012, which was well below the historical average.
This record rainfall directly coincides with more cloud cover, which artificially reduces the length of the days, resulting in Jacaranda trees thinking it is earlier in the year since the average temperatures are also lower.
These significant climate shifts have left researchers like Dr Barrett guessing how delayed the flowering period will be this year.
“So far, only a minority of Jacaranda trees are in flower, with most trees still in bud or with only a few flowers,” Dr Barrett said.
“This is not for a lack of flower buds through as most trees are bursting with buds from the record rains, so this Jacaranda season promises to be spectacular once it arrives,” he said.
Emergence of flowers
These famous trees have unique prominent purple flowers, traditionally putting on their best show from late October – early to November and Dr Barrett suggests these trees, widely known for their beauty, can contribute to our understanding of how plants are affected by climate change.
Jacarandas are quite resilient to various changes in climate as they come from a naturally arid area with a short rain season. But being a popular street tree, the effect of a changing climate is visually evident since the tree is bare for before they come into bloom.