If you are planting your flower beds and hanging baskets, keep our dwindling population of pollinators in mind and please don’t plant double flowers.
People love double flowers, with their densely packed petals they can be beautiful and make a real impact in a garden. But they are bad news for our insect pollinators: bees, hoverflies, butterflies, wasps and beetles.
Double flowers are mutations, coding errors, in which the cells that are supposed to become stamens are mistakenly instructed to develop into extra petals. This means fewer or no stamens at all and little or no pollen. Many pollinators depend entirely on pollen; it’s the reason they have come to visit the flower.
For the butterflies and bees that come to a double flower looking for nectar, the situation is not much better. The flower’s nectaries are generally found at the very base of the petals; all the extra petals in a double flower make access to the nectaries difficult and sometimes impossible. So, double flowers are not a good source of nectar either.
Pollinators respond to very simple messages from flowers, signalled by colour and scent. Double flowers continue to send these signals and insects continue to respond. This is a terrible waste of energy for flying insects which are always balancing the value of a food source against the energy expended in finding it: a dangerous equation to get wrong, not just for individual insects but also for insect colonies where the next generation is being reared.
All over the world, bee populations are collapsing and we know the major causes are habitat loss and modern farming methods. Our gardens (and country parks) need to be oases of plenty in the increasingly sterile agricultural desert that so much of our countryside is becoming.
Try old-fashioned, single flowered petunias, pelargoniums and fuchsias in your hanging baskets. Instead of pom-pom daisies in your flower beds, let the single flowered sort flourish in your lawn. Think of double flowered marigolds and marguerites as newfangled nonsense and insist on pollen bearing stamens and accessible nectaries. Befriend the bees.