Appreciating Native Pollinators
By Xander Rose
Pollinating insects are important for pollinating flowers so that they become fruit. Many fruiting plants need to be pollinated, which means needing more than one variety of tree. Fruit set also requires some kind of pollinator in most cases. The vast majority of pollinators are insects.
The most famous pollinator, the honeybee, hails originally from Eurasia. She’s a foreigner! Honeybees came to North America with Europeans. In a sense, I would argue that honeybees can be analogized to cattle. They have crowded housing. They behave much the same way as one another, preferring certain flowers and having low genetic diversity. They're like the cows of the insect world! Honeybees can be good pollinators of many fruit trees and berry bushes, but did you know that much of the heavy lifting in many situations is probably actually done by native pollinators?
Blueberries and other members of the Ericaceae family have urn-shaped flowers that honeybees fail to pollinate well. The plants need bumblebees to use special buzz pollination on their flowers for maximal fruit set. I love seeing bumblebees visiting blueberry and huckleberry flowers when I'm working in the orchards or greenhouses at Raintree Nursery.
Here are some great resources on native bumblebees:
U.S. Forest Service
Xerces Society for Invertebrate Conservation
Fig 1. A bumblebee visits comfrey, an excellent flowering plant for pollinators in the orchard.
Fig 2. A bumblebee flying to a blueberry bush.
Unlike honeybees, which nest in tree cavities (as feral or wild bees) or in man-made hives, bumblebees nest underground. Sometimes they nest in disused rodent holes, for instance. Honeybee colonies have honey stores and a a reserve of workers to make it through the winter. Bumblebee bee colonies survive the winter as a lone queen carrying sperm and eggs. Those queens emerge in early spring ready to forage and start their season anew by producing daughter/sister workers. This story so far is revealing in a couple ways: Firstly, bumblebees need patches of native habitat, rougher, messier places around the garden where their shallow nests will be undisturbed by low-cutting lawnmowers, compacting feet or wheels, poisonous sprays, let alone the out and out destruction wrought by tilling, graveling, paving, and so on. Secondly, they need early spring flowers with nectar and pollen to boost their budding colonies. The queens need habitat conducive for foraging and nesting. I have seen queens seeming to be confused as to the location of their nest after going on some crucial early foraging foray. Apparently, my weed wacker wrecked the location of their nest. My answer to this issue is to have a light and natural hand with the brush control--mowing, weed wacking, or scything (talk about being close to the Earth!) somewhat haphazardly and incompletely each time. This may make for a messier look, but those rough spots harbor wildflowers and bee nests.
There are many other lesser known native pollinating insects. Flies and beetles pollinate the unusual paw paw tree’s flowers (a topic for a future post). Solitary bees and wasps can be diverse and beneficial where allowed through a diversity of habitat. Mason bees gather mud and pollen for packing their eggs into small holes. I enjoy watching them fly to and fro with these gleanings as they come home to the nest box my girlfriend and I built for them. It’s quite easy and enjoyable to provide habitat for mason bees. Raintree sells material to do just that!
The world of pollinating insects is diverse and I encourage you to learn more through observation in your own yard and orchard, as well as through reading.
Happy growing! Because, after all, change is the only constant. -Xander Rose