Hot annuals - and unusual summers

The Scarboro Garden Scene
Hot annuals - and unusual summers
If I’m right, every year in Calgary is different from the preceding ones in terms of weather. Clearly weather averages are useful statistically, but we have to expect the unexpected. Environment Canada uses thirty year averages from specific weather stations. From the last thirty years period on record, ending 2010, the average temperature in July was about 17 degrees Celsius, or 63° F, but this does not report our + 30° C highs and low overnight temperatures. This variation has a profound impact on the development of plants; if the highs come too quickly, as they did this year, plants “bolt” and their blooms can be short-lived, or in the case of some leafy vegetables, become bitter and go to seed quickly. June is typically the wettest (ask the garden tour organizers!) and a lot of our rainfall occurs with summer storms. The average frost-free period for Calgary is typically 117 days although the frost date can very easily occur one week later in spring or one week earlier in the fall (in contrast Edmonton at the City Centre airport has 135 frost free days). Compared to the thirty years between 1961 and 1990, we have more total precipitation, and the climate is warmer, although the mean January temperature increased, summers have remained about the same.
Early blooming flowers such as bloodroot (Sanguinaria) and Bishop’s Hat (Epimedium) did well this spring and some places rapidly growing perennials – the delightfully scented tall phlox called ‘David’ for instance - grew laterally and covered some bare spots in yards. For the first time in decades, self-seeded elderberries are covered with scarlet fruit, and some yew too are decorated with “berries”. I’m not very lucky with begonias, but this summer they and annual geraniums add some startling colour to a dark area. Must plant some more next year.
September issue newsletter 304 words, August 3, 2017.