MASTER GARDENERS: How to mainstream the bees in our everyday lives
This past June I attended the Upper Midwest Regional Garden Conference at the Landscape Arboretum in Chaska. One of the keynote addresses was given by Marla Spivak, entomology professor at the University of Minnesota. She spoke on "Mainstreaming Pollinators in our Everyday Lives" and I would like to highlight some of her main points.
Did you know that Minnesota has over 400 different native bees? This doesn't include honeybees that are not native. Most of our bees are ground nesters. The nests are difficult to find since the bees dig in and the hole disappears. They can dig through light mulch, but not a thick layer. They prefer bare ground. Because the nests are so elusive research is hard to conduct. Only 10 percent of native bees nest in cavities or stems. They will nest in the hollow stems of sumac, asters, roses, monarda, goldenrod and some grasses to name a few. It's important when cutting perennials back in fall to leave stems about a foot tall for bees to use as nesting sites. There are also nesting sculptures available commercially, but beware that they often have tubes that are too short for bees to use.
Diversity is the greater goal in the garden. It increases disease resistance and beneficial insects as well as nourishing the soil, preventing nutrient runoff and ecosystem resilience. Also, diversified gardens are more interesting and attractive. All types of bees increase with a greater variety of flowers grown, thus diversifying food sources available. Plant the flowers that produce the most pollens. Generally, hybridizing decreases pollen production and those plants with a large number of petals on the flower are not as appealing to pollinators. Pollen producing plants do not necessarily have to be native. My garden was buzzing with bees this year. They favored zinnias, cosmos, rodgersia, cimicifuga, coneflowers and hyssop, just to name a few. Consider growing bee friendly lawns. Lawns that have flowers that can be mowed such as clover (there are over 40 varieties available) and the ever dreaded Creeping Charlie and dandelions are loved by bees.
Bumble bees are in decline in Minnesota. Some of the varieties that are declining are the Rusty Patch (endangered), yellow-banded, American and yellow. There are some things we as gardeners and land owners can do. Citizen Science is the latest way to help keep tabs on the numbers and locations of bees. A couple of sites where you can report what bees you have on your property are—www.bumblebeewatch.org and www.inaturalist.org. And the site www.Bumblebee.org asks that you take photos of bees from a couple of angles, upload with sighting information and the bees will be verified by experts as to the variety. At inaturalist.org bees and plants are identified by a committee of identifiers, not necessarily experts. MN Bee Atlas has volunteers across the state that keep track of bumble routes. These are all wonderful resources for us to help keep track of the numbers, types of bees and sites where the bees are found. Consider helping next year as you garden.