Page 11 - 2018 Sonoma County Gardener's Resource Guide
P. 11

OASIS cont’d from page 110
   and the more exotic dahlias don’t qualify (even though they are beautiful!), since pollinators cannot access the center of the flower. Some plants produce more nectar and pollen than others, including all types of Salvia, poppies, milkweed, borage, native California buckwheats, asters, scabiosa, lavender, Gaillardia, hyssop, veronica, clover, phacelia and sunflowers. Butterflies especially seem to like verbena, milkweed, daisies, coneflowers, cosmos, yarrow, and zinnias. For late summer and early fall forage, plant goldenrod in the spring and sow a final round of sunflowers, phacelia, and annual buckwheat in mid to late July.
Trees and shrubs are another great source of late summer food for bees
and other pollinators, providing a three-dimensional field of flowers. Some recommended species include Chaste tree (Vitex), Bottlebrush, Red-flowering gum, and Crape Myrtle, particularly the white variety. If you plant these types of trees, you will know you are helping the pollinators because your yard will be audibly buzzing when they are in bloom!
Native bees such as the familiar black and yellow bumble bees, black carpenter bees, bright green sweat bees, iridescent blue mason bees, and the long-horned bee are common in Sonoma County. Except for the bumble bee, which creates a colony underground, these native bees are solitary, nesting in hollow stems or in the ground.
 Leaving areas in your yard or garden undisturbed will maximize
nesting spaces for native bees, as will leaving your garden a bit
messy through the winter.
 Some natives nest in the hollow stems of last year’s flowers. If you do have to trim your plants in the fall, place the cut stems gently on the compost pile and don’t disturb until well into spring to give the overwintering bees a chance to start the new year. Planting at least part of your garden in blooming California natives ensures a match between the native bees’ nutritional needs and available food.
To ensure your garden or farm is truly bee-friendly, avoid use of bee-toxic pesticides, especially neonicotinoids, which persist in plants and soil for months to years, making the pollen and nectar toxic to bees for a long time. Even low doses of these insecticides have been found to compromise the bees’ immune system, making them more vulnerable to diseases carried by the Varroa mite. Neonicotinoids and some fungicides also impair bees’ ability to reproduce, and even affect the bees’ ability to navigate their way back to the colony after foraging.
  Having a pesticide-free garden also requires starting with
neonicotinoid-free plants, but finding them can be a challenge. A recent study by Friends of the Earth and Pesticide Research Institute showed that in 2014, 51% of bee-attractive plants sampled from big box stores like Home Depot and Lowes contained neonicotinoids. With the results of the study in hand, Friends of the Earth and consumers asked the big box stores to eliminate these insecticides from their plants, or at least label the plants so gardeners could make informed choices. Many nurseries responded to pressure from retail stores and consumers, and by 2016, only 23% of plants tested from big-box stores contained neonicotinoids, and the treated plants were labeled as having been treated. It’s an improvement, but there is still progress to be made.
Buying local is the best way to ensure that plants you buy are
safe for pollinators. Many of the local nurseries in Sonoma County do not use neonicotinoids and can provide a clean source of plants for your garden or farm. Ask the staff to be sure.
Happy gardening!
   Susan E. Kegley, Ph.D., Principal and CEO
Useful Resources for Gardeners:
Pesticide Research Institute, Inc., 3883 Petaluma Hill Rd, Santa Rosa, CA 95404
Attracting Native Pollinators, Xerces Society
Farming for Bees, Xerces Society
Bee-Friendly Gardening Resources, Pesticide Research Institute
Best Bee Plants for California, UC Berkeley Urban Bee Lab
Pest Smart Web allows you to find out which pesticide products are toxic to bees (also available as a free iOS app), Pesticide Research Institute
Neonicotinoid Insecticides in Garden Plants, Friends of the Earth and Pesticide Research Institute
California Bees and Blooms: A Guide for Gardeners and Naturalists by Gordon W. Frankie, Robbin W. Thorp, Rollin E. Coville, Barbara Ertter
The Bee-Friendly Garden: Design an Abundant, Flower-Filled Yard that Nurtures Bees and Supports Biodiversity by Kate Frey, Bretchen LeBuhn, Leslie Lindell
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