By: Jane Sorensen, Northeast Pollinator Plants and River Berry Farm
All images courtesy of author
Thinking of starting or expanding a native plant business, or simply increasing their presence in your landscape? Now is the time, and with a pollinator bent.
Nursery plants with good information
You all know that a much larger audience is catching on to the need to include native plants in their landscape. Meanwhile, the plight of pollinators is also hitting the news; articles abound with recommendations of planting native plants for pollinators. And yet, knowing just which plants are best and where to find them can be elusive. I hope this article can be an encouragement for more folks to grow native and naturalized perennials for pollinators, and better yet, offer them to their community.
Why Pollinators?
First off, why focus on pollinators, and just who are they? Three quarters of the world’s flowering plants and over a third of the world’s food require animal pollination.¹ Frankly, without pollinators, biodiversity comes to a screeching halt and we humans go hungry.
Who are the pollinators? Pollinators include bees, wasps, beetles, flies, butterflies, moths, hummingbirds, and more. Among these, bees stand out as the most crucial yet they, like many of our pollinators, are in trouble. Honeybees (Apis mellifera) are actually a European species, so it is the native bees, many of which are solitary bees, that are declining. According to Xerces Society, more than 28% of North American bumblebees are threatened, while 50% of leafcutter bees and 27% of mason bees are at risk.²
Selecting Plant Species
Like us, pollinators prefer familiar foods as they often are not attracted to, or simply cannot digest, food that is exotic to them.³ Sure, all native plants are great, but some are more beneficial than others for attracting and nourishing pollinators. It is also important to select plants that are relevant to the native pollinators of your region, due to a long co-evolutionary history.
Baptisia australis (blue false indigo)
Several organizations have developed regional pollinator plant lists. You can simply adopt one of these lists, such as from Pollinator.org, or you can do some deeper diving and gain a wealth of knowledge along the way. I created my pollinator plant palette by using the Xerces Society list made available through the Lady Bird Johnson Wildflower Center website. This is an amazing, interactive resource where you can filter for your state, sun and soil conditions, flower time, and color.
To get to this filtering option is not immediately apparent. On the wildflower.org site, navigate to the “Plant Information” tab, then select “Plant Lists.” Scroll down to find a slew of options under the “Plants for Pollinators” heading, including “Special Value to Native Bees.” “Butterflies and Moths of North America,” “Provides Nesting Materials/Structure for Native Bees.” To utilize filters, click “Narrow Your Search” and you will have a nice long list of excellent regional pollinator plant options which you will likely want to whittle down some. Things to consider in fine tuning this list would be native status, survival strategies (where on the spectrum of well-behaved to rogue spreaders), disease/pest issues, and the plant appearance.
Checking Native Status
The Biota of North America, North American Plant Atlas (BONAP NAPA) website provides an opportunity to see in which counties each species is native or naturalized and whether the plant is rare or endangered in your area. (A word of caution: when viewing the county-level map, the lighter green color means native to that county, while the darker green color for the rest of the state is just filler color.)
Though this sounds counterintuitive, you should not grow and plant rare or threatened plants, identified with yellow or orange on the BONAP NAPA maps, unless grown from seeds of local ecotype, which are nearly impossible to procure, as this is considered a genetic threat to the remaining local population(s).
Some of the plants on your list will likely be introduced/naturalized, identified by the teal color on the BONAP NAPA maps. It is good to focus on native plants, but I do indeed include many naturalized plants in my offerings if they are not invasive and proven to be good for pollinators, as a hedge against climate change.
Question of Cultivars
You will notice that none of the plants on the Xerces filtered list are cultivars. However, much of what is offered at garden centers and nurseries as native plants are cultivars, which are plants that have been manipulated by breeders, generally to be more attractive for us humans, such as different flower or leaf/stem color, larger or double flowering, and more compact growth habit. The question is whether these cultivars are as beneficial for the pollinators. Several researchers have, and are continuing to, explore this question.4 Current findings indicate that it’s a complex matter, but generally, pollinators favor true native species.
Research is ongoing, and until a conclusive verdict is reached, if our goal is to create pollinator habitat, I recommend embracing the aesthetic preferred by pollinators and opt for what they have evolved to interact with–the true native. Aesthetic modifications can impact the pollinators’ ability to find the species, while alterations to the flowering time can significantly impact the alignment of adult pollinator foraging windows. And finally, it is advisable to avoid double flowers, as the sexual organs of the flowers have been mutated to appear as petals, offering little to no foraging opportunities for the pollinators.
True native species: Echinacea purpurea (purple coneflower) Pycnanthemum tenuifolium (narrow leaf mt. mint) and Agastache foeniculum (purple giant hyssop)
Survival Strategies, Appearance and Pest/Disease Issues
Plants exhibit varying survival strategies, resulting in a spectrum from “well-behaved” to more rambunctious plants (a concept adopted from Gerritsen/Oudolf, Dream Plants for the Natural Garden, 2000). “Well-behaved” plants tend to be long-lived and stay in place–in other words, more “garden-worthy.” On the other end of the spectrum are plants that are short-lived and ensure their species’ survival through excessive re-seeding or spreading with rhizomatic roots–more suited to a meadow or cottage garden. You and customers should know where plants fall on this spectrum. However, a note of caution: a somewhat well-behaved species can become a bit rambunctious if it’s super happy with the sun/soil conditions, so the “well-behaved” designation may need to be taken with a grain of salt.
Determining the plant’s appearance, how it behaves, as well as current pest and disease issues, can take a little web or book searching. I simply love the Missouri Botanical Garden Plant Finder website for native plant explorations, where the information is thoroughly accessible and concise. A favorite book is William Cullina’s Wildflowers; A Guide to Growing and Propagating Native Flowers of North America, which offers his personal experience and anecdotes on a wealth of native perennials.
Supporting a Diversity of Pollinators
Even if we focus just on bees, their diverse needs can be daunting. In Vermont, there are over 350 native bee species. The vast majority are solitary nesting bees, which emerge as adults to forage for about three to four weeks, varying by species from early spring to late fall. Each species has different tongue lengths, impacting what kind of flowers from which they can gather nectar, and differing body size, which generally determines how far they can forage and what size and shape of flower they can land on or fit within. Meanwhile, about ten percent of our native bees are social nesters. These are mostly bumblebees, who have overlapping generations in the nest, producing foraging bees, again from early spring to late fall. Given this, just considering the bees’ needs, it is important to provide constant and overlapping flowering with a variety of flower shapes, colors, and sizes.
Next you need to factor in the butterflies, moths, and beetles that require host plants on which to lay their eggs—often very specialized relationships, requiring specific plant species or plant families from which the hatching pollinator larva can eat. Most of us are familiar with this relationship with monarch butterflies and the milkweed genus.
Asclepias syriaca (common milkweed)
Xerces Society recommends offering at least ten species of carefully selected plants, with three species flowering early, three mid-season, and three late-season, and to include at least one native grass, which can serve as a host plant for many species as well as nesting material. In one research effort, it was observed that the diversity of pollinators plateaued when more than twenty well-selected plant species were offered. However, choosing to offer greater diversity of plant species can only ensure more opportunity to support some of those specialized relationships. Really, there’s lots we still do not know!
Backyard pollinator haven
Finding Seeds
Ideally, plants should be cultivated from local ecotype seeds, which are seeds collected from wild plants in your eco-region. To identify your eco-region, explore the USDA Level III Ecoregions maps online. Over the long history of evolution, regional differences have resulted in species adapting to their specific surroundings. Consequently, plants grown from seeds collected in one region may exhibit flowering times that differ, either slightly or significantly, from plants that normally grow in that region. This difference in phenology has ripple effects on other organisms, such as pollinators, whose emergence and needs may no longer align.
The interest in local ecotype seeds is blossoming, though the availability is somewhat lagging. In New England, there is Eco59, born out of efforts of the CT Natural Organic Farmers Association to engage botanists, farmers, and volunteers, resulting in a web-based store where you can purchase seeds. The Wild Seed Project, in Maine, is a non-profit that offers wild- and garden-collected seeds in small quantities, and the Native Plant Trust, formerly known as the New England Wildflower Society, is embarking on an effort to greatly expand access to local ecotype seeds, but with an initial focus on seeds for restoration projects. With diligent web-searching you can find some wild-collected seeds from local grass-roots businesses.
An even better source is wild seed collecting yourself using a trusted dichotomous plant key such as Newcomb’s Wildflower Guide or the Native Plant Trust’s handy on-line plant key, Go Botany. Ensure the plant is not rare or endangered in your county, as collecting without a special permit is a crime. Permission is needed to collect on someone else’s property, and do not collect on Federal or State lands without permission, as this is also, generally, a crime. Collect seeds, not plants, and ideally collect a few seeds from fifty to one hundred plants for greater genetic diversity.
Meanwhile, there are some great Midwestern, Western and a few Mid-Atlantic U.S. seed businesses that offer many desirable species of pollinator plants, if you are unable to find them locally. Prairie Moon Nursery is the go-to for many native perennial growers, offering an impressive informative website.
Growing from Seed
Most seeds of native plants need to experience winter to germinate. To simulate winter, you can provide “cold-moist stratification” by mixing potting mix with equal amount of fine vermiculite or sand, lightly moisten, put a couple tablespoons in a freezer bag. Add the seeds, and store in the fridge for the suggested amount of time. Most need sixty days, though some require just ten, or up to one hundred twenty days, while others, such as asters and most grasses, do not need any cold-moist stratification. Prairie Moon Nursery website is a great source of species germination information.
Alternatively, you can simply seed trays or pots in late fall, set outside, and cover trays or pots with chicken wire to keep out wildlife until you see germination in the spring. Or, simply seed directly where you want them to grow, using soil preparation as you would for any perennial seeding, to reduce weed pressure.
Trays of seedlings
Selling Pollinator Plants
Interest is booming! Sales of our pollinator plants, both at the farm (River Berry Farm in Fairfax, VT) since 2012 and through our online regional nursery (Northeast Pollinator Plants) since 2015, have grown consistently each year, experiencing a yearly increase of at least twenty percent.
Clear information is critical to help customers be successful in establishing their pollinator gardens and habitat enhancements. This includes providing guidelines for constant and overlapping flowering from early spring to late fall, and clear signage for each species that identifies the flowering time, color, sun and soil needs, height, native status, and some general comments on the appearance and growth strategies. We offer our plants as single species and as collections for different sun/soil conditions and garden versus naturalizing settings, for customers who are not interested in making species decisions.
Opportunities
Retail customers are seeking these plants. We have customers driving well over an hour to shop for pollinator plants at our farm. Our on-line nursery grew out of my giving presentations hours away from the farm, prompting people to ask where they could get these plants. Every nursery and garden center should include these plants in their offerings.
Meanwhile, this is creating a great opportunity for wholesale nurseries to offer plugs of pollinator plants to regional retail nurseries who are not interested in fussing with that cold-moist stratification. Furthermore, there is a burgeoning group of landscape architects, designers, and contractors who are struggling to find sources of native plants specified in their projects. This year we had many calls, emails and visits from this crowd requesting larger quantities than what we could provide.
If you have been wondering if the market is ready, I can confirm: yes, it is time. You can grease the wheels by writing articles in local papers and giving talks in libraries and community centers, as well as at your nursery.
As greenhouse growers, nursery and garden center owners, educators, and researchers, you provide a great service advocating for and making available the very plants the pollinators need. As we domesticate the landscape, it is up to us, domesticators, to provide habitat in our landscapes.
Sources
¹United States Department of Agriculture, The Importance of Pollinators website page.
² Xerces Society for Invertebrate Conservation website, Endangered Species Conservation – Wild Bee Conservation page.
³ Homegrown National Park website, (Douglas) Tallamy’s Hub page.
4 White, Annie, “From Nursery to Nature: Evaluating Native Herbaceous Flowering Plants Versus Native Cultivars for Pollinator Habitat Restoration” (2016). Graduate College Dissertations and Theses. 626.2016.
About the Author:
Jane Sorenson
Jane Sorensen is passionate about pollinator habitat enhancement and loves any opportunity to spread the word. She is a full-time farmer and co-owner of River Berry Farm, an organic fruit and vegetable farm in Fairfax, Vermont, where she grows and sells native plants for pollinators on the farm and through her on-line nursery, Northeast Pollinator Plants. Jane has recently retired from the University of Vermont where she taught one course, Landscape Design for Pollinators, and is a retired landscape architect with 14 years experience.
Northeast Pollinator Plants, owner
Northeast Pollinator Plants is an on-line regional nursery offering native and naturalized perennials, and a few shrubs, that have been carefully selected to ensure each s of special value to native bees and bumblebees, our most important pollinators.
River Berry Farm, co-owner
River Berry Farm is a family-owned organic small fruit and vegetable farm in Fairfax, VT, that also sells in-person native and naturalized perennials for pollinators through the farm stand from June 1st to the end of September.
Northeast Wild Seed Collectors, coordinator
Northeast Wild Seed Collectors is a group of passionate native plant advocates and volunteers who utilize a website to coordinate efforts in collecting local ecotype seeds from New England and New York states of plants that are of special value to pollinators and other wildlife.
Click here to access Jane’s helpful document with common names for Vermont Pollinator Palettes
