Friday, July 26, 2013

Flowering Plants that Native Bees Love

Bumblebee on cup plant (Silphium perfoliatum)
In high summer, many gardeners take some time simply enjoy their gardens. It's not too soon, however, to be thinking about next year. I've started collecting seeds of native flowers, to sow immediately or to save and cold stratify for next spring's planting, as the case requires. If you want to make your garden more bee-friendly next year, here are some planting guidelines and a list of species suggestions. I have experience with every plant listed and therefore feel I can recommend them. Don't forget, many perennials can be planted in early fall. Though I am focusing on native bees, honey bees will also of course take advantage of the foraging opportunities you offer.  

In general
Bees and other pollinators such as butterflies prefer sunny areas that are protected from wind and offer plenty of different kind of flowers. Ideally there would be several types of flowers in bloom spring through fall. In my yard, different areas might be blooming at different times--but I have a small yard, so the bees don't seem to mind. Those with larger yards might plan for groupings of different varieties in one or more beds. No matter what size your yard or garden is, every area planted with mostly native flowers will be beneficial for pollinators, particularly in urban and suburban areas, because it increases the availability of pollen and nectar these creatures need to thrive. The plants listed here are suitable for large parts of the Midwest. This is not a complete list and something that works well for you might be left off. There are many more species of Midwestern prairie and savannah plants that could be included. If you live elsewhere, this simple rule applies: bees native to an area are best adapted to plants native to that area. Finding out what those plants are and adding them to your garden can be a worthwhile, enjoyable endeavor.

Learn more about native plants and use them in your garden 

According to the Xerces Society, "research suggests native plants are four times more attractive to native bees than exotic flowers." Garden herbs (allowed to flower) and annuals, especially heirloom varieties, can also provide good foraging. Avoid hybrids that have double blooms, since they often do not produce as much nectar or pollen. Native flowering shrubs also provide nectar and pollen for bees and often serve as host plants for caterpillars. If using non-native garden plants, please make sure they are not invasive in your area. Also, certain kinds of weeds (but definitely not all!) can be a good thing: early-appearing bumblebees appreciate dandelions and creeping Charlie, for example.  

Plan to have something in bloom all season long
Bees and butterflies fly at different times. They, and humans, appreciate a garden that has many varieties of flowers and a long season of bloom. If you mostly have native perennials, it's good to slip some long flowering annuals in various areas to keep going during perennials' in-between times. This is also a good strategy when starting a new area of young natives that might not bloom the first year.

Group flowers together in attractive drifts 
This old design rule makes good sense to bees as well as humans. Bees find good forage by sight. Clusters of flowers of the same species will attract more pollinators and enable better foraging than individual plants scattered through the garden. Where space allows, plant big clumps (at least four feet in diameter) or sizable drifts, which might require five or more plants.

Plant different types of flowers to support a wide variety of bees

Bees range in size from minute sweatbees at less than 1/8-in. to robust carpenter bees over an inch long. They also have different tongue lengths, and need suitable flowers. Some prefer flat, daisy-like flowers, while others prefer tubular blossoms. They are also attracted to brightly colored flowers that are blue, white, purple, and yellow--nor, in my observation, do they object to red.

Do not use insecticides in your garden

Even organic pesticides can be harmful. Other chemicals such as fungicides can be dangerous--to humans as well as bees.  I have discussed the dangers of neonicotinoids in "City Bees, Country Bees." Habitat loss and insecticide use are the two main threats to bees and butterflies. A well-run ecological garden attracts birds and beneficial insects that help keep pests to a minimum.

Suitable Plants
Spring can be a difficult time for native bees, especially in urban areas with few early-blooming perennials. Queen bumblebees emerge at this time and fly for several weeks foraging before settling down to make their nests.An asterisk denotes species that flourish in areas that become shady when the trees leaf out.
Native Perennials
Columbine Aquilegia canadensis
*Violets Viola spp.
*Virginia bluebells Mertensia pulmonoides
*Virginia waterleaf Hydrophyllum spp.

*Wild geranium Geranium spp.
Wild indigo Baptisia spp.
Non-native Perennials
Siberian Squill Scilla spp.
Chives Allium spp.
Periwinkle Vinca minor
Summer-Late Summer (into Fall) is a halcyon period for native bees if the foraging is good. Plenty of sources of nectar and pollen ensure good populations, which in turn insure a continuation of the species. Male bees use flowers as sheltered places to rest while they look for young queens with whom to mate.
Native Perennials 
Aster Aster spp.
Beebalm Monarda spp.

Asters Aster spp.
Black-eyed Susan Rudbeckia spp.
Blazing Star Liatris spp.
Butterfly weed Asclepias tuberosa
Compass plant Silphium lanciatum
Cup plant Silphium perfoliatum
Giant hyssop Agastache spp.
Goldenrod Solidago spp.
Joe-pye weed Eupatorium spp.
Milkweed Asclepias spp.
Penstemon Penstemon
Liatris Liatris spp.
Phlox Phlox spp.
Purple coneflower Echinacea spp.
Rattlesnake master Eryngium spp.
Sage Salvia spp.
Spiderwort Tradescantia spp.
Sunflower Helianthus spp.
Tickseed Coreopsis spp.
Non-native Annuals and Perennials 
Basil Ocimum spp.
Catmint Nepeta spp.
Cosmos Cosmos spp.
English lavender Lavandula
Marjoram Origanum
Marigold Tagetes
Parsley Petroselinum crispum
Rosemary Rosmarinus
Salvia Salvia spp.
Stonecrop Sedum spp.
Zinnia Zinnia
Flowering Trees, Shrubs and Fruits offer more foraging opportunities from early spring through summer, and are often butterflies' preferred host plants.
Natives are best
Chokeberry Aronia spp.
Dogwood Cornus spp.
Lilac Syringa vulgaris
Raspberry Rubus
Redbud Cercis canadensis
Rose Rosa spp.
Serviceberry Amelanchier spp.
Strawberry Fragaria
Viburnum Viburnum spp.

Willow Salix spp.
Note: This is part of a series about how urban areas might offer the best hope and some of the best habitat for native bees. "City Bees, Country Bees" is here; "City Bees, Country Bees, Part 2" is here. The next post in this series will focus on what bees need besides flowers and will offer a few suggestions to vegetable gardeners as well.

References: Illinois Wildflowers,;  Xerces Society Fact Sheets, “Upper Midwest Plants for Native Bees” and “Butterfly Gardening,” the Xerces Society for Invertebrate Conservation,; USDA.

Related Posts:
Creating a Hummingbird Habitat
In Praise of Native Shrubs
Attracting Native Pollinators
An Excellent, Timeless Book

Monday, July 8, 2013

Urban Neighborhoods Can Be Good for Native Bees

Honeybees are not the only ones in trouble--bumblebees are too. This is the second of a two part series that discusses how urban areas might be bumblebees’ and other native bees’ best chance for survival. Part one is here.  

In City and Country
Leafcutter Bee
The morning of June 19th, before leaving for a retreat, I went out in my urban, Chicago-area backyard to see how the bees were doing. I do this nearly every day, spring through fall, several times a day if I’m at home and working on gardening chores. Warm, with a light breeze, the sun lighting up the flowering plants--it was perfect pollinator weather. Sure enough, back towards the alley, in an area perhaps 10’x20’, a couple of bumblebees were assembled at the spiderwort, honeybees and carpenter bees browsed the nepeta, and at least two other species cruised the coreopsis and the raspberries. I also saw a leafcutter bee and quite a few minute creatures resting on leaves, their golden or green metallic abdomens gleaming, that could be bee or wasp or flower fly. There were also assorted hover flies, wasps and a few butterflies. In my yard, this is completely normal, and what I would expect to see in those conditions.

Later that afternoon a friend and I strolled the retreat property in Putnam County, scouting for bees. Owned and maintained by Illinois Quakers, the twelve acres of grass and mostly native trees such as black walnuts, oaks, ash and maples also include a couple of old field/quasi-prairie areas and remnant hedgerows anchored by some gnarly old osage orange trees. The meetinghouse sits on a slight rise, slight enough that only people from these parts would probably even notice, particularly when the corn is up. Because of extreme spring rains, the corn and soy were not well-grown. You could sit at a picnic table under a maple just southwest of the meetinghouse and look south, southeast and southwest all the way to the horizon. The effect is one of sitting on an island surrounded by a sea of corn and soy, with here and there a distant cluster of farm buildings, metal roofs glimmering in the sun, embraced by their own clusters of trees. The sky, often cluttered with piled-high cumulus clouds, is a dominant element in the composition. To my Midwestern eyes it is restful to be able to see so far, and the contours of the land contain a spare beauty. Visitors from other parts of the world or the U.S., however, find this landscape surprising or even shocking: surprisingly green, open, and flat; shockingly large and uniform.

So, as I said, my friend and I, that first afternoon, patrolled the grounds. We found exactly two bees in a small patch of clover. They looked like some kind of solitary native species but were unfamiliar to me.

A Country Landscape Toxic to Pollinators
At various times during the next four days I would sit at that table, contemplating the landscape and considering this triumph of the industrial farming system that supplies corn and soy to the entire world. Aldo Leopold, in his mid-twentieth century essay “Illinois Bus Ride,” accurately pegs the monotone Illinois landscape and inhabitants’ lack of knowledge regarding the native prairie; the clean-farming practices he describes have only become more predominant since then. I sat with the constant awareness that in those vast fields every single plant as far as the eye could see had doubtless been treated with, among other dangerous chemical products, fungicides and neonicotinoids, and so, virtually every plant in that landscape was toxic to bees. There are vanishingly few refuges.

The common saying goes that every third bite of food is enabled by bees. But what does that really mean? Simply that bees and other pollinators are crucial to the conversion of the sun’s energy into food we can eat. A landscape without pollinators may as well be a dead landscape. It is like a machine missing certain crucial gears that allow it to function: complexity is radically diminished, energy flows depleted, life processes interrupted, and spacial-temporal-energy-matter relationships crucial to ecosystem functioning distorted. A lack of pollinators tears holes in the web of physical and biological relationships that enable the sun’s energy to be converted into matter, i.e. the plant based biological systems that simultaneously embody and power life on earth. The landscape I was viewing was imbued with an ineluctably tragic quality. Sure enough, though during my visit I saw other insect life--a few butterflies, various moths, beetles, flies, mosquitoes and gnats, a dragonfly-- I never saw another bee. When I got back home, I immediately went out in the backyard. Bees galore.

These were not-one-time-only experiences or comparisons. I go to that place regularly and am just as regularly struck by the differences between the biodiversity there and in Chicago. This is not to say more biodiverse areas don’t exist in and around Putnam County. A hobby beekeeper of my acquaintance maintains a combination bee meadow/natural area on 30 acres a few miles from from the meetinghouse; Matthiesson and Starved Rock State Parks are fairly close by; the Dixon Waterfowl Refuge, a restored area along the Illinois River, lies ten miles away. Yet these are small in comparison with the vast areas of monocropping that prevail there and throughout the state--and the country--an area so large that in seasonal time lapse satellite photos you can see how thousands of square miles of bare brown fields become green in spring and summer. When driving back to Chicago (there is no other way to travel between the two), the experience, paradoxically, is that as the concrete increases, so does biodiversity, so that one has a sense of moving from barrenness into lushness.

 Biodiverse habitat makes a huge difference for bees and native bees seem to be in trouble--or not--depending on where they live. Two studies bear this out. In the first, native bee populations (bumble bees were not included in this study) were counted Carlinville, Illinois. This study compared species counts done in the late 19th century and the 1970’s with the last couple of years. In the 1970’s, 82% of species remained. Since the ‘70’s, the number of species has declined by half. A primary reason seems to have been loss of habitat. Meanwhile, two currently ongoing studies of bees in various habitats (including green roofs) in the Chicago area show that in comparison with a count in the 1930’s, numbers of species (approximately 150) have remained stable, though there is some difference in species between then and now. (Please see 8/10/14 update below.)

What Cities Have: Neglected Acreage and Contiguous Back and Front Yards
A Chicago Neighborhood
My personal experience and these kinds of observations and studies lead me believe that, in North America, at least, cities hold untapped potential as pollinator reserves. Most farmers continue to plow up ever more habitat, remove land from conservation reserve programs and use neonics and other pesticides with abandon. It seems clear that until these farming practices change, it will be up to urbanites, whether in cities, towns or those suburbs that have abandoned the atavistic, pristine-lawn aesthetic, to see to it that our bees survive. With regard to honeybees this situation has been recognized for some years, as the proliferation of urban beekeeping has demonstrated. It is equally important for our native bees. Metro areas really are bees’ last best hope.