The weather outside my window this morning felt more like mid-March than early May as I walked down Queen Street, noticing how barren many of Toronto’s trees still look. It’s not just my imagination – Toronto’s trees are indeed running behind schedule this spring, and residents across the city are wondering why their neighborhoods haven’t yet transformed into the lush green canopies we expect by now.
“We’re seeing a definite delay in leaf-out and flowering times across the Greater Toronto Area this year,” explains Dr. Sandy Smith, Professor of Forestry at the University of Toronto. “Many species are approximately two weeks behind their typical schedule, which is quite significant when you consider the relatively short growing season we have in this region.”
According to Toronto and Region Conservation Authority (TRCA) monitoring data, average soil temperatures remained below the critical 10°C threshold until late April, significantly later than in recent years. Trees require consistent soil warming before they commit their energy to producing leaves and flowers – a biological safety mechanism that prevents damage from late frosts.
The delayed blooming isn’t limited to one species or area. From High Park’s famous cherry blossoms to the maple-lined residential streets of Leaside, nature’s spring schedule is running late across the board. The City of Toronto’s Parks and Forestry Division reports that annual maintenance operations like mulching and early pruning have been extended to accommodate the shifted growing season.
What’s behind this botanical tardiness? Climate scientists point to several factors working in concert.
“The extended cold we experienced through March and April, coupled with significant precipitation, created unfavorable conditions for early spring growth,” notes Misha Kerr, senior meteorologist with Environment Canada’s Ontario Weather Service. “While we’ve had warm days interspersed, trees respond more to the overall pattern and soil conditions rather than brief warm spells.”
This winter’s weather patterns have been particularly unusual, with dramatic temperature fluctuations ranging from record-breaking warmth in February to persistent cold snaps throughout April. The Toronto weather station at Pearson International Airport recorded 12 days below freezing in April 2024, compared to just 4 such days in April 2023.
For Toronto’s diverse urban forest, which includes over 11.5 million trees representing more than 100 different species, the response to these conditions varies significantly. Native species like sugar maples and white pines have evolved alongside our climate’s rhythms and remain well-adapted to occasional late springs, while some non-native ornamentals may struggle with the extended cold.
Walking through Trinity Bellwoods Park yesterday afternoon, I noticed a few early-blooming magnolias finally opening their buds, their pink and white flowers providing a welcome splash of color against the predominantly brown landscape. Nearby, a group of residents were discussing the unusual spring timeline while pointing at still-dormant oak trees.
“I’ve lived in this neighborhood for 38 years, and I can’t remember the trees being this late to wake up,” said Ellen Morneau, a retired schoolteacher and local resident. “My garden is weeks behind too – I’m only just seeing my daffodils come up now.”
For Toronto’s ecosystem, these delays create ripple effects beyond just aesthetics. The urban forest plays a crucial role in moderating temperature, managing stormwater runoff, and providing habitat for wildlife – functions that are temporarily reduced until full leaf-out occurs.
“The timing of spring leaf emergence affects everything from bird migration to insect hatching to carbon sequestration,” explains Dr. Smith. “Urban trees already face numerous stressors in city environments, so any significant alteration to their growth cycles warrants attention.”
The City of Toronto’s Biodiversity Strategy, which aims to enhance and protect the city’s natural heritage, includes monitoring protocols for tracking these phenological changes – the study of seasonal natural phenomena – as potential indicators of climate change impacts.
Recent research from the University of Toronto’s Faculty of Forestry suggests that while occasional late springs are normal, the increasing frequency of weather extremes presents challenges for urban forest management. Their 2023 study documente
