Essential Pollinators in Your Edible Garden
By Karin Davidson Taylor, Education Program Officer, Royal Botanical Gardens.
Each winter and spring, we spend time sorting through our seeds to decide what we’d like to have in our summer garden — tomatoes, squash, peas, beans, herbs, broccoli, and so much more. While making these decisions, do we also consider what insects might be visiting the flowers of these plants? You can also consider incorporating other flowering plants in your food garden, that will help support these pollinators all season long.
Bumblebees: the Master Pollinators
Bumblebees are master pollinators and so very important in a food garden. There are long-tongued and short-tongued species with the length of the tongue determining the type of flower that the bee will go to. This group of insects then is able to pollinate a wide array of different flower types. Being a larger bee, they are strong enough to push their way into tight flowers, forcing the petals open to reach the nectar, and in turn will get some pollen on its body hairs that will potentially fertilize another flower of the same species. This group however is best known for their ‘buzz’ pollination. Some flowering plants, like tomatoes, have evolved to make it hard for any insect to get its pollen. Bumblebees can contract their flight muscles, which produce strong vibrations that they direct on to the anther using their legs and mouth parts. This results in an ‘explosion’ of pollen grains from the tip of the anther. Some of this pollen will be collected into the bumblebee’s pollen sacs on its legs, but a few grains will be missed and go on to fertilize the next tomato flower visited. Other examples of plants that benefit from bumblebee pollination are blueberries, eggplants, and borage.
Squash Plants Need This Bee
Whether you have zucchini, pumpkin, gourds, or cucumbers in your garden, plants from the squash family all produce large yellow flowers. The pollen in the male flower is large, sticky and spiny and, as it turns out, unattractive to honeybees so they are not the best pollinator for this plant. There is a popular belief that honeybees pollinate most of our food crops, but they don’t pollinate these plants. There is a highly specialized native solitary bee, the Hoary Squash Bee, that has co-evolved with squash. A female will arrive at the male flowers just as it opens in the early morning, collect the pollen on her hairy legs and body, and after visiting a number of plants, take it back to her underground nest and use it to provide her brood with food. By the time the other bees arrive, its too late; in this case the early bee gets the pollen. By the way, males and unmated females have been found sleeping in the wilted flower in the late afternoon or evening. SHHHH… do not disturb ZZZZZ.
Leave your Broccoli and Lettuce to Flower
Lastly, have you ever thought to leave your leafy and brassicas vegetables, such as lettuce or broccoli, to flower. They produce fragrant yellow and white flowers that are attractive to many different species of bees providing a rich source of nectar and pollen to help those bees that overwinter. This is especially true of bumblebee queens that need extra food to survive the winter in their underground nest.
And what garden is complete with out a few flowers? Your food garden is no exception. The food plants will flower at different times and there will be occasions when nothing is flowering, but our native bees are hungry. Remember to include some herbs such as mint and sage as well as both native and non-native, but definitely nectar-producing flowers in your garden to support these valuable pollinators all growing season long. Here are some suggestions: Penstemon, Virginia Mountain Mint, Salvia, Zinnia, Boneset, Echinacea, and in later summer and fall, Joe Pye Weed, Goldenrod, and New England Aster.