If you thought summer was a bummer this year, you aren’t alone – local flora wasn’t too impressed either.
According to local naturalist and phenologist Bill Merilees, a strong majority of the 180 species of plants on his Departure Bay property that he has been keeping records of for the past 16 years flowered considerably later than usual in Summer 2011. Compared to the average first flowering date, 2011 was found to be about 10 days later than the average of the previous 15 years, a significant difference says Merilees.
“Normally, as Nanaimo experiences periods of warm and cool spring weather, flowering often shows a speeding up or slowing down of flowering. 2011 was different. This spring got off to a slow start and this trend continued in almost a straight line right into July,” said Merilees in a synopsis of his findings this year.
Environment Canada shows spring and early summer temperatures and precipitation weren’t far off historic averages — June temperatures were bang on average — but the organization doesn’t track sunlight hours, which could have been the difference.
Phenology is the study of phenomena through time, in particular periodic biological events such as bird migration, the flowering of plants or the hatches of insects. For flowering plants, the dates of flowering are determined by by a plant’s genetic code, and then correlated to annual climatic conditions that include temperature, soil moisture and rainfall, day length and hours of sunlight, and exposure.
Because of the direct response of an individual plant or a population of plants to this diverse variety of environmental factors, said Merilees, there is possibly no better measurement for comparing and contrasting one location with another.
His baseline for flowering median dates includes 2,068 observations over the past 16 years.
In 2011, of the 180 plants he observed (the average plant was observed 9.6 times throughout the spring and summer), Merilees found that 171 flowered later than average, seven were earlier and two flowered on the expected date.
Flowering on mid-Vancouver Island begins in January with Surge Laurel and hazelnut, peaks during May when many plants flower, and concludes in July with Rattlesnake Plantain and the Vancouver Island beggar-tick.
Some plants seem to prefer the less-than-stellar weather, however. Merilees’s notes say the evergreen huckleberry, which normally flowers in mid-May, bloomed on April 1 while bitter cherry and cleavers were about 20 days ahead of historic averages.
“To determine if these observations are a true reflection of these species flowering responses to local environmental conditions we will have to wait for a repeat year with very similar conditions to 2011,” he said. “[Something] serious gardeners may not wish to repeat.”
Phenology is first recorded in Solomon 2:12, who wrote of the activity in 974 B.C. The longest continuous record keeping of flowering plants in the world is believed to be record keeping of cherry trees in Japan, which have records dating back 12 centuries. In North America, the longest ongoing records date back to about 1850.