Yellow shouts spring in the garden

If the Irish spring has a colour, then surely it is yellow. Just think of daffodils. Or the egg-yolk yellow celandines and dandelions pushing their way through the ground. Or the pale lemon flowers of our native primrose, or the fluffy, sweetly-scented blooms of the Mimosa trees adding a flash of exotic colour to sheltered urban gardens at this time of year.

Even the hazel’s dangling catkins are a pale lemon-yellow, courtesy of the pollen that covers them like a fine dust.

So why so many yellow spring-flowering plants? One possible answer is that the colour yellow is very easily seen by emerging pollinating insects (to whom, somewhat strangely, it appears blue).

Another possible answer is the fact that, other than green, yellow is the colour most easily manufactured by plants. Some biologists also suggest that yellow flowers give spring-flowering plants a reproductive advantage by enabling them to heat up more easily.

Highest visibility

Whatever the botanical explanation for its springtime prevalence, yellow is certainly the colour that lifts our spirits after long winter months spent indoors. It is the colour of sunlight, hope and happiness, as well as the colour of highest visibility.

Just think of Emma Stone's dress in La La Land, a pop of brilliant canary-yellow against those lavender-blue Hollywood skies. Or the golden dress that Marilyn Monroe wore back in 1962 when she famously serenaded JFK on his 45th birthday (which sold at auction last November for a whopping $4.8 million).

Yellow is also the colour of Van Gogh’s sunflowers, or at least it was when he painted them, before more than a century of exposure to bright sunlight made the pigment (a toxic paint no longer used, called chrome-yellow) gradually fade and discolour to a dirty brown.

Enduring popularity

Yet despite the prevalence of yellow flowers in the spring garden and the enduring popularity of sunflowers like those that Van Gogh painted, yellow isn't a popular colour in the Irish summer garden. Why? Yet again, light – and in particular, the intensity and angle of natural sunlight – may be part of the reason.  In springtime, the sun is lower in the sky while the strength of its rays are weaker, with the result that yellow flowers appear bright, but not unduly so. By summer, the sun is higher and the intensity of its rays far greater, so that many gardeners perceive yellow flowers as being unpleasantly bright and gaudy.

But perhaps the answer is far simpler. Maybe after our yellow Irish spring, we’ve had our utter fill of yellow flowers by the time summer finally arrives.