To See Like a Bee

Orange hawkweed, Hieracium aurantiacum appears somewhat unexciting to the human eye, but its ultraviolet extravaganza is an irresistible invitation to bees. 

 

By Thomas Christopher

Next spring, I plan to replace a large part of my threadbare lawn with a meadow.  The conditions are favorable: the same poor, sandy clay soil that has crippled my lawn is ideally suited to the establishment of native meadow wildflowers and grasses, which compete better with weeds in such conditions than they do on richer soils. But I don’t want just any meadow; I want to plant something attractive to the local bees. Of course, I want it to be attractive to my own eye as well. Therein lies the conflict, or at least a need for compromise.

Bees see flowers differently than you or I do, and not just because the insects view them as a source of pollen and nectar, while for humans they gratify less practical, aesthetic yearnings. Bees also see light differently than we do, perceiving colors in the ultraviolet range that are imperceptible to us, and not seeing most reds (this different vision is not uncommon among color-sensitive insects).

This means that the scarlet ‘American Beauty’ rose which looks so glorious to us is drab, even insignificant, to a bee – in fact, red flowers tend to be bird pollinated, as birds do see reds. Conversely, many flowers that appear relatively uninteresting to us are, because they are intricately painted in ultraviolet shades, highly visible and attractive to bees. Orange hawkweed, Hieracium aurantiacum, for example, a widespread introduced weed, is just an orange-ish, dandelion look-alike to us, whereas to a bee it is a brightly checkered ultraviolet extravaganza.  This high visibility is surely connected with its reproductive success and the way it has spread so completely throughout the northern three quarters of our continent.

Designing a mix that best serves the bees isn’t simple, as I learned when I contacted Mark Fiely, the horticulturist at Ernst Conservation Seeds in Meadville, Pennsylvania, a leading supplier of native plant seed mixes. There are several considerations in selecting the various elements.  First of all, Ernst focuses on native plants for its native pollinator mixes because, having co-evolved with these flowers, the insects interact with them better.

A long and continuous season of bloom provides the best diet for pollinators, and so the pollinator mixes, Mark Fiely explains, include such early blooming species as golden Alexanders (Zizia aurea) and hairy beardtongue (Penstemon hirsutus) as well as late bloomers as aromatic aster (Aster oblongifolius) and showy goldenrod (Solidago speciosa). Then, too, they must include a diversity of flower types because different types of bees, as well as other pollinators, are adapted to different floral structures.  Native bumblebees, for example, include long, medium, and short-tongued species, with each group feeding at different shapes of flowers.  In addition, some species of flowers are included because of the special nutrition they provide. For example, turtlehead (Chelone glabra) has substances in its nectar that helps bees rid themselves of parasitic mites, while wild senna (Senna hebecarpa) produces pollen that from a nutritional standpoint is nearly perfect for bumblebees.

A call to Dr. Harland Patch, a research scientist in the Department of Entomology at Pennsylvania State University brought another perspective. Color, he pointed out, is of less interest to insect pollinators than the aromas of the plants, many of which humans cannot even perceive. The safest approach to planting a pollinator friendly meadow, he said, was to include the greatest possible diversity of wild-type native flowering plants. Pre-packaged seed mixes are, typically, relatively poor in species diversity because to include more becomes prohibitively expensive. As a result, Dr. Patch recommended consulting the lists of pollinator-friendly plants published by the Xerces Society (https:xerces.org) and Pollinator Partnership (www.pollinator.org). Plants of recommended species can be inserted into the planting area, ideally in its second year, to enrich the diversity of whatever seed mix I select.

It’s easy to make a case for the economic and ecological benefits of pollinators, yet their populations are in decline, largely from loss of habitat and food sources.  It doesn’t seem too much for me to put aside my horticultural lust for the biggest and brightest flowers, and settle for a landscape that, while less picturesque to the human eye, is instead buzzing with life.  That, certainly, is a garden well worth having.

 

Thomas Christopher is the co-author of “Garden Revolution” (Timber Press, 2016) and is a volunteer at Berkshire Botanical Garden. berkshirebotanical.org

Be-a-Better-Gardener is a community service of Berkshire Botanical Garden, one of the nation’s oldest botanical gardens in Stockbridge, MA. Its mission to provide knowledge of gardening and the environment through 25 display gardens and a diverse range of classes informs and inspires thousands of students and visitors on horticultural topics every year.  Thomas Christopher is the co-author of Garden Revolution (Timber press, 2016) and is a volunteer at Berkshire Botanical Garden. berkshirebotanical.org.