Douglas Justice, associate director of UBC Botanical Garden and Centre for Plant Research, talks about the changing colours of fall and the joys of gardening in colder weather.
Why do leaves change colour in the fall?
Leaves change colour as chlorophyll, which is the green pigment responsible for capturing the sun’s energy, starts to break down and be reabsorbed by the plant in response to cooler temperatures and diminishing light. As the chlorophyll disappears from the leaves other compounds, such as yellow pigments, are unmasked, and still others, including red pigments, are actively being synthesized.
Why do some leaves turn dark red?
It is thought that the darker pigments serve a protective function—a kind of sunscreen—for the leaves, preventing breakdown of the tissues, while allowing sufficient photosynthetic activity to power reabsorption of nutrients from the leaves into the stems.
What’s great about gardening during autumn? What plants flourish in the fall and winter?
It’s an opportunity to showcase the beauty of stems and bark, berries and evergreen leaves, and those plants that flower in the fall, winter or early spring. Berried plants, as well as the colourful stems of osiers (shrub willows and shrub dogwoods) are typical constituents of West Coast winter gardens. Besides colour, these provide structure, mass and verticality. There are all kinds of low shrubs, ferns, grasses and grass-like plants, bulbs and other herbaceous plants, that can lend both colour and texture on the garden floor.