Pollinator Protection in Winter: Save The Stems
Summer’s bright flowers and wavy grasses are dry and grey these days. Many would say they’re downright ugly this time of year—if they haven’t already been chopped and sent to the brush dump. But there’s another perspective circulating among folks who offer ways to protect pollinators. The idea is called “Save the Stems,” calling upon gardeners and landscapers to leave dead-head flowers standing until spring.
Why? Many, perhaps most, perennial plant stalks are hollow, it turns out. Vertical hollow stems provide spring nesting opportunities for bees and other beneficial insects, according to the Xerces Society For Invertebrate Conservation and other organizations. Some insects also use stems as winter habitat.
"The uncut standing stalks resist mold and decomposition," says Sarah Foltz Jordan, senior pollinator conservation specialist at Xerces. "The freshness of the stem cut seems to matter to bees [when they're scouting for egg-laying sites in spring]. If you cut in the spring, those stem entrances are cleaner." She continues, "In addition, some stem-nesters appear to be restricted to upright stems."
And what about the birds? Elevated seed heads are also important for them. When the seeds remain on the stalks, birds get less competition from rodents and other small mammals. For details on “Save the Stems” see xerces.org/publications/fact-sheets/nesting-overwintering-habitat.
For some people, though, winter stems and deadhead flowers raise the same issues as ‘leave the leaves.” This approach seems to force a choice between a traditional neat-and-tidy landscape or protecting pollinators.
Landscape professional Petie Reed of East Lyme says, "It can be a hard decision for my customers. They want their landscapes tidy, but they also want to help pollinators and birds." She says that many people are sensitive to neighborhood expectations and it’s tough when neighbors are adamant about the traditional neat-and-tidy look.
Xerces spokesperson Deborah Seiler suggests the choices don't need to be either-or.
"Gardeners bothered by the standing or fallen stems could take another approach. They can create diversified nesting habitat by moving the stems to a designated brush pile elsewhere.
Brush piles also provide habitat for a variety of beneficial invertebrates and other wildlife," she says.
Seiler also reminds us that not all bees are stem-nesters. "Ground-nesting bees need access to some bare, exposed soil," she says.
Landscaper Petie Reed says, “It’s reasonable to practice two or three different standards of neatness in the same yard. For instance, one of my customers raked and trimmed everything in the foundation garden but let the dead-head perennials and grasses stand everywhere else.”
In addition to these compromises, there's another option: When selecting plants in the spring, look for perennials, grasses, shrubs, and trees that stand up well in winter weather. The options are more numerous than many people think. (See a list at the end of this article.)
Nancy DuBrule-Clemente, founder of Natureworks in Northford, observes, "I love the great coneflower in winter--it's so architectural. I also love the fluffy white seedpods of smooth blue aster. I leave them standing for the birds," she says.
Petie Reed calls little bluestem, green-headed coneflower, and mountain mint "sturdy winter plants" that stand up to wind, ice, and snow.
My own nominees include goldenrods, fairy candles (a.k.a. Culver's root), and New York ironweed (though it may need staking). I allow wild bergamot and purple coneflower to stand until April. Among grasses, I like the winter seed heads of northern sea oats and switchgrass. Finally, I'd nominate hyssop-leaved boneset (a.k.a. thoroughwort), an under-used perennial that offers a beautiful seed "bouquet" in winter.
Shrubs and trees
Beyond the perennial border, many native woody plants add beauty to a landscape all year. They also have much to offer birds and pollinators.
"I admire the winter look of smooth hydrangea, a lace cap form, right outside my window every day,” says Nancy DuBrule-Clemente. “I love red-twig dogwood 'Cardinal’," the brightest red variety I've seen." She adds, "I also love Atlantic white cedar, Chamaecyparis thyoides 'Glauca' alongside my winterberries and evergreen leucothoe."
There are many other native trees and shrubs that stand out on a dark January day. Consider native inkberries, rhododendrons, mountain laurels, and oak leaf hydrangeas. Native viburnums and chokeberries hold colorful berries deep into winter months.
Among trees, American hollies stand out in the winter landscape. Winter king and Washington hawthorns offer bright red berries. River birches and American sycamores have beautiful bark.
Junipers and white pines—both shrub and tree forms—grace the winter landscape with their distinctive green tones.
In your winter travels, why not keep your eyes open for native plants that impress you with their sturdiness? If you need help finding the right native plants, Research native plants for your yard and community, visit plantfinder.nativeplanttrust.org. You’ll enjoy them during the growing season, the colder season, and when you think about the bird and pollinator resources they provide.
Native flowers and grasses that stay sturdy in winter:
- Anise hyssop, Agastache foeniculum
- Bush clover, Lespedeza capitata
- Fairy candles, Veronicastrum virginicum
- Great coneflower, Rudbeckia maxima
- Goldenrod, Solidago spp.
- Green headed coneflower, Rudbeckia laciniata
- Hyssop-leaved boneset, Eupatorium hyssopifolium
- Little bluestem, Schizachyrium scoparium
- Mountain mint, Pycnanthemum muticum
- New York ironweed, Vernonia noveborensis
- Northern sea oats, Chasmanthium latifolium
- Smooth blue aster, Symphotrichum leave
- Switchgrass, Panicum virgatum
Native shrubs and trees that are attractive in winter:
- American hollies, Ilex opaca
- American sycamore, Plantanus occidentalis
- Atlantic white cedar, Chamaecyparis thyoides “Glauca” or “Top Point”
- Chokeberries, Photinia arbutifolia, P. melanocarpa, P. floribunda
- Inkberries, Ilex glabra
- Leucothoe, Leucothoe spp.; Mountain laurels, Kalmia latifolia
- Native viburnums, Viburnum spp.
- Oakleaf hydrangea, Hydrangea quercifolia
- Red-twig dogwood ‘Cardinal,” Cornus sericea
- Rhododendrons, Rhododendron maximum, R. minus; River birches, Betula nigra
- Smooth hydrangea, Hydrangea arborescens
- Washington hawthorns , Cratagus phaenopyrum
- Winter king hawthorn, Crataegus veridis
- Winterberry, Ilex verticillata
- Junipers, Juniperus spp.; White pines, Pinus strobus.
Kathy Connolly is an Old Saybrook landscape designer who writes and speaks on landscape ecology. Contact her for a list of perennials, grasses, trees, and shrubs that have winter appeal. Kathy@SpeakingofLandscapes.com.