The witch hazel down the road has just finished flowering, but two weeks ago the scent of honey hung around it even when the air was below freezing.
A little further up there is an osmanthus, which also has a sweet scent. It’s not for attracting pollinators, which is often the reason for plants to produce a smell, because it’s still winter. And many plants produce fragrance in their bark, leaves or seeds as well; think about bay leaves, cinnamon, nutmeg and caraway.
We love them and make good use of them in cooking, but what do they do for the plant?
All volatile oils have some qualities in common, to a greater or lesser degree. They are antimicrobial, anti-inflammatory and – when you eat them or rub them on your skin – anti-spasmodic. For plants, they can help to repel insects and other predators that may damage them, and they kill disease microbes as well. If the scent is released when the plant is damaged, it acts as a signal to ward off predators, and other plants around will respond by readying their defence mechanisms. Sometimes, the smell will attract creatures that feed on the attacking insects.
And sometimes we don’t fully understand what it’s for, like the witch hazel in winter, except to give us joy in February.
It’s also worth remembering that plants don’t mind a bit of predation. As long as the entire plant is not destroyed, they thrive on being ‘pruned’, as it were, becoming more vigorous and living longer. You could almost say that it is part of a healthy life-cycle. The point of having defences is not to remain untouched, it’s to keep predation to an acceptable level. There’s a lesson for us there. We need our diseases to keep us healthy; it’s the balance that’s important.