In GardenRant’s 18-year history we’ve tackled more than a few controversial topics, including Marianne’s recent post about advocates of pure nativism, to which Ranter emeritus Thomas Christopher then responded. Lively discussions ensued! I love seeing disagreements aired and explored honestly and based in facts. And with an open mind!
In that vein, a recent episode of Thomas’s excellent podcast Growing Greener explored “Blending Natives and Non-Native Plants” through an interview with Karen Bussolini. She’s a garden writer, photographer, speaker and coach who also works as horticultural advisor to White Flower Farm. (We first hear about the company’s sustainable practices, which are indeed impressive.)
Getting to the subject of growing both native and nonnative plants, Karen’s stance is that “It’s a large house and there’s room for everyone,” while citing the study showing greater biodiversity in the Great Dixter garden than in the surrounding countryside.
How to Support MORE Pollinators by Including Nonnative Plants
Quoting Karen: “When it comes to pollinators you want mass and connectivity, so you want a lot of flowers. And the kind of rule of thumb is you need to have at least three plants blooming together from the earliest in the season to the very latest.”
Daffodils at River Farm, AHS headquarters in Virginia.
“Abundance and diversity of flowers leads to abundance and diversity of insect life, and I’ve come to think of the purpose of gardening is supporting insects. They’re so important! So those early bulbs – when the earliest bees come out of the ground there’s not a lot of food. So crocuses and snowdrops and early bulbs like that, daffodils – the earliest ones, it’s probably only the honeybees that come out on a warm day but pollinators are like the canaries in the coalmine. They tell you about the whole habitat, the whole ecosystem. And I have certainly seen a lot of bumblebees in my daffodils. So there’s food there.
Hummingbird on salvia in my garden.
“A lot of annuals – we have some highly bred ones that don’t really feed anyone but we have some annuals that are just absolutely buzzing with native pollinators and hummingbirds and butterflies. So plants like verbena bonariensis nasturtiums, ageratums, and there are a lot of annuals that are – some of them are tender perennials that are native to Central and South America or the far Southwest, but our bees don’t know that! They absolutely flock to the salvias, zinnias, tithonia. Sunflowers are not native here – they’re native to the Midwest – but they’re one of the absolute best. Dahlias, the big fluffy ones that are double – no. But you plant a few single dahlias and you’re going to see a whole lot of native bees feeding from them. Agastache, some of the Southwestern native ones, are just absolute bee magnets and the hummingbirds love them, too.
“You mention hostas. Boy oh boy there are some great hostas that have really attractive flowers – not the old-fashioned ones – that are absolutely full of bees and hummingbirds.
Alliums in my garden.
“Early in the season, hellebores. I would not be without alliums, both the bulbs and the perennial alliums, especially the bulbs – they are absolute bee magnets. And a lot of perennials that have umbel shaped flowers, the tiny flowers feed lots of tiny insects.
“Patrinia. We have dauchus dara, (also known as the flowering carrot, wild carrot, or Queen Anne’s lace), which has maroon flowers and pink flowers and white flowers.
Nepeta in one of my adopted gardens.
“How can you be without nepetas or calaminthas? I know that my yard at home is full of ajuga, and those blue flowers just absolutely come with bees.
“Early morning – bumblebees can fly earlier and farther than any other kind of bees and sedum ‘Autumn Joy’ and Japanese anemones were completely covered.
“Then they’re not out yet but in the late fall a lot of native plants – the asters and the goldenrods are so important, they’re really critical food sources for bees and butterflies, but what are those things supposed to eat when those things have passed? We have extended falls, so the native plants have gone by and the bees are still active and that’s when they’re going to really flock to the anemones but also to monkshood.
What about feeding caterpillars?
Black swallowtail caterpillar on bronze fennel in my garden.
Tom mentions special functions that native plants can perform, like being larval hosts for caterpillars, many of which are adapted only to specific native plants. He continues: “So I think it’s important to include both, but you make a very persuasive case that you can be feeding and benefiting a lot of wildlife by including nonnative plants in your garden.”
About feeding caterpillars, Karen says, “I’m glad you mention larval food plants because there are such tightly integrated relationships with native plants. But the next kind of class of plants that I would not be without are in the vegetable gardens and in the flower gardens – herbs. I love fennel and bronze fennel and dill and it’s a little bit hard to harvest them sometimes because the swallowtail butterflies use that whole family as a larval food plant. To my surprise, the daucus dara, which is a Welsh carrot, I had some growing… and saw black swallowtail caterpillars. So plants like mint and oregano and basil and other herbs are important for pollinators – I don’t think they’re larval food plants but certainly fennel and dill are.”
And I love this – Karen recommends that we “just be observant, spend time in the garden looking. What plants are buzzing with pollinators?” And her advice to listeners who want to be environmentally responsible but still enjoy traditional garden favorites? “Go for it. You have to enjoy it. Educate yourself.”
On the growing dominance of strict nativism
Referring to the strict nativism that Marianne and others are complaining about, Tom says “Whatever native plant purists may say, the leaders of the movement do NOT say you should only grow native plants. Douglas Tallamy has never said that you should exclude introduced beloved nonnative plants from your garden. Larry Weaner, who I’ve worked with, includes both in his garden because he wants to keep his clients, as well as the wildlife happy.”
That’s true, though I wish Tallamy in particular would encourage inclusion of nonnatives for the benefits outlined above. But there are plenty of people and organizations who recommend ONLY native plants, for pollinator and rain gardens or generally. They include writers Benjamin Vogt, Ginny Stibolt and Jenny Reed, and these organizations: Xerces Society, National Wildlife Federation, Pollinator Partnership, Wild Ones, Chesapeake Bay Foundation, U.S. Fish and Wildlife Service, Alliance for the Chesapeake Bay, Penn State Extension, Ohio State, Cornell Extension, Michigan State, (which repeats debunked claims about natives having deeper roots), the USDA and even Architectural Digest Magazine.
(I found just a few organizations that include nonnatives in lists of plants for pollinators or rain gardens – Oregon State, U. New Hampshire and the Cincinnati Zoo and Botanic Garden. And many gardening publications.)
Then there are the untold numbers of government and nonprofit grants that forbid the use of nonnatives in projects they fund. And the agencies targeting plants like the eucalyptus trees in California for removal because they’re not native there.
It’s not just “traditionalists”
Thomas mentions the many gardeners who are “reluctant to give up introduced garden plants, the old favorites that didn’t originate many of them in North America but are really hard not to love. You know, bearded irises, hybrid roses, hostas, et cetera, things that have been favorites since most gardeners’ childhoods. And at times this has become a point of conflict. I’ve been told by resentful traditionalists that they’re tired of being told that they are irresponsible for growing anything other than natives.”
Well, I’m one of those gardeners growing both natives and nonnatives but not because I’m keeping “traditional” garden plants like those listed, which I grew tired of long ago. In the last 15 years or so I’ve ditched the lawn (in two gardens) and filled the spaces with plants from around the world that attract pollinators and provide other ecological services, as well as beauty for me and for passersby.
So what to call gardeners like me? How about inclusive eco-friendly gardeners? Yeah, that fits.
Thanks for this defense of harmless non-native plants. Those who prefer native plants should be free to plant them. My only objection to their purist preference is their insistence that non-native plants must be destroyed, particularly on public land using herbicide.
The Washington Post recently published another installment of Dana Milbank’s columns about his attempt to transform a derelict farm into a native landscape. He has abandoned his formerly cautious approach to using herbicides and is now using aerial drones to convert a hayfield into a native meadow of grass and forbs:
“To save the birds, I brought in this big bird: a 10-foot-square, Chinese-made drone with 8 propellers, capable of carrying 10 gallons of fluid, in this case glyphosate, to kill the grass in my hayfield. (It might seem counterintuitive to douse a field in herbicide to help nature, but conservationists broadly endorse the practice.)”
Milbank has abandoned his cautious use of herbicide and is now aerial spraying from a drone 30 feet over his head, while he watches without wearing any protective gear:
“Shanley, in shorts, sneakers and fishing shirt, plopped in a lawn chair in the shade of my barn and, using a control pad with two joysticks, sent the drone into the sky… In a moment, the beast was airborne and, from a height of about 30 feet, spraying death on my hayfield. It sprayed the fescue. It sprayed the Johnson grass. It sprayed the foxtail. It returned, flew over the barn — and sprayed me with glyphosate. Programming error. “Sorry about that,” Shanley said. My eyes burned for two days.”
Milbank has the right to poison himself, his land, and the animals that live on his land. Although the applicator may be breaking laws (he would be in California) by not wearing any protective equipment), Milbank isn’t doing anything illegal. If I weren’t reading his story in the mainstream media with a national following, I wouldn’t be talking about what he’s doing. I’m talking about Milbank’s dangerous use of herbicides because he has a big audience and his audience displays their ignorance of the dangers in over 1,400 comments.
The reader comments on Milbank’s latest article are uniformly positive, as were comments on his earlier installments about his war on nature. Most comments are short expressions of unqualified praise, such as “You are doing holy work,” or “God bless you.”
A handful of comments (including mine) express concern about the indiscriminate use of glyphosate. The few dissenting readers are blasted by Milbank’s supporters. Some of their responses betray ignorance of herbicides:
• “It’s not Round Up; it’s a safe herbicide.” In fact, Milbank says he’s using glyphosate, which is the active ingredient in Round Up.
• “He said nothing about dousing. It looks like a selective approach. In some cases, there is no practical alternative.” In fact, Milbank says explicitly that he’s spraying 10 gallons of herbicide 30 feet over the ground from an aerial drone. Does that sound selective?
The most common defense of Milbank’s herbicide spraying was that it only needs to be done once, with an occasional follow up prescribed burn. Milbank doesn’t actually claim that herbicide only needs to be sprayed once, but his supporters wish to believe that because they don’t understand how glyphosate works.
Glyphosate kills only the top-growth of an actively growing plant. It won’t kill the seed bank in a hayfield that has grown for decades, perhaps for 100 years. For as long as the seed bank lives, it will produce new top-growth every year that will have to be sprayed again with glyphosate. That is the scenario we have witnessed in our public parks in the San Francisco Bay Area for over 25 years, where similar attempts to eradicate established non-native plants have persisted, without success.
Does Millbank not see the irony in using a drone to spray glyphosate over a field? Somewhere Rachel Carson’s ghost is weeping.
Did anyone comment on the potential for “drift”? I worked for the Maine Forest Service years ago when they were spraying to fight the spruce budworm (misnamed, of course). They sprayed from planes. There were so many places that required buffer zones, no-spray zones, etc. even when they were using the biological Bacillus thuringiensis (sp?). There were spotters who followed in different planes to make sure the spray didn’t drift onto land where it didn’t belong. If the wind was too high, they didn’t spray. Even with a drone at 30 ft. there’s going to be drift – quite possibly off HIS property onto someone else’s who doesn’t want glyphosate! And to say that’s not Round-Up is bs, as you noted. So sad that this guy has such a following. People seem to gravitate to the easy way out. It seems so contradictory to “restore” land using poison to plant natives that probably won’t make it because the soil is poisoned. Maybe this is judgemental but I’d say it was simply stupid and not something I would emulate or respect.
I have a suspicion that these supporters of Dana Millbank using Round-up, then evading the truth about its harms, are probably voting Red this week.
Just a little guess.
Talking in terms of teams is unhelpful to the argument or to building coalitions of concerned people from all walks of life and political persuasion.
And if we did go red team/blue team generalizations on this, it has been my experience that the opposite is FAR more true, which is such a crazy shift that it is one of the main things that made me realize that it is a religious movement, not a scientific one. – MW
I haven’t yet listened to the podcast mentioned, but will do so carefully. In the meantime, something that’s missing in this post is any discussion about WHICH pollinators a garden is designed to attract. Flowers with pollen and/or nectar will certainly attract generalist insects such as non-native honey bees, bumblebees, and other native insects. But what about the many specialist insects? For example, Jarrod Fowler has stated that about 25% of the 770 or so bees native to the Eastern United States specialize in gathering pollen from one or a few genera. https://jarrodfowler.com/specialist_bees.html. A garden without these plants won’t attract the specialist insects, nor provide support for them.
This is an issue separate from the need for host plants for insects, but both issues factor into the discussion about the benefits of a garden to insects. It’s certainly possible to have a garden that appeals to both generalists and specialists. Perhaps if a gardener clarifies his/her goals for their garden, it will help ease the tension that arises in this discussion. I suggest that native-only gardeners could consider acknowledging that a generalist garden can be functional and beautiful, and non-native/mixed gardeners could consider acknowledging that a generalist garden has its limitations in support of specialist insects. That leaves room for discussion about this issue.
The debate about “specialist” insects is mostly a red herring because most nativists are not aware that most genera have both native and non-native species among them. I recently had a debate with a purist nativist who did not understand that a bee that uses a native species of clover is probably capable of also using non-native clover, the ubiquitous lawn weed that we can see is swarming with bees. For same reason, he could not understand that a bee that uses a native sunflower it also capable of using an agricultural crop of non-native sunflowers. Many native plants are closely related to non-native plants. Most are chemically and nutritionally similar and are equally useful to insects. If nativists had a solid understanding of evolution, they would know this.
Nativists are slowly admitting that monarchs are capable of using non-native tropical milkweed. In fact, in experimental gardens they show a consistent preference for tropical milkweed. So, now nativists fight their battle by claiming that tropical milkweed is harmful to monarchs for a variety of reasons, all easily debunked by academic entomologists:
Because of global warming, monarchs have begun to breed during the winter months in California and the existence of tropical milkweed in gardens in coastal California has made that possible: “the [monarch] population boom in the Bay Area had not been seen before. It was unusually warm that fall, which may have accounted for the numbers. And tropical milkweed, which unlike native milkweed flowers through the winter and creates a suitable habitat for breeding, was abundant in gardens.” (“The Story of the Butterflies,” Endria Richardson, BayNature, Summer 2022)
Scientists with a commitment to the survival of monarchs have welcomed this development: “But the growth of local, breeding monarchs is seen, at least by some, as a sign of the resilience of the monarchs, their ability to find new ways to persist in the face of an increasingly threatened migration. Might we be seeing the growth of a resident population of monarchs in the Bay Area
The Nature Police have succeeded in getting the sale of tropical milkweed banned in Contra Costa, Marin, San Mateo and Ventura counties. Academic entomologist have pushed back against this harmful ban in an article published by The Monterey Herald, San Jose Mercury, Marin Independent Journal, and East Bay Times:
• “Hugh Dingle, a retired University of California at Davis entomology professor who has studied monarch butterfly migration for more than two decades, said the bans are “basically a wasted effort” and that the focus should be on larger threats such as pesticide and herbicide use. All species of milkweed carry parasites that can affect monarch populations, Dingle said.”
• “Arthur Shapiro, a UC Davis professor who has studied monarch butterflies for the past six decades, described the rationale behind the bans as “hogwash.” Shapiro, Dingle and other researchers said winter breeding among monarch butterflies is a relatively new behavior and one influenced by warmer winter temperatures caused by climate change.”
• “David James, an associate entomology professor at Washington State University who has studied monarch butterfly breeding and migration in the Bay Area, said there is a case to be made about the tropical milkweed as being a vital resource for the monarchs in a changing climate.”
• “Leslie McGinnis, a UC Berkeley doctoral candidate studying monarch populations and working with gardeners in the East Bay, said the bans take a “simplistic view” of the threats that monarchs face, including the fact that many native milkweed plants supplied to nurseries can also be sprayed with pesticides. The bans, she said, can work to disenfranchise or demonize people that have tropical milkweed who instead could be partners in working to help restore monarch populations.”
Native plant advocates are wedded to a past that is long gone. The climate has changed and it will continue to change. Monarchs and other animals are trying to adapt to the changed conditions. Their survival depends on their ability to adapt. The native plant movement has become a form of climate change denial. Their irrational hatred of introduced plants is damaging the environment with herbicides and harming wildlife. There is no evidence that tropical milkweed is harmful to monarchs.
It makes sense from an evolutionary standpoint that insects would be able to use closely related species, either native or non-native. And yes, I agree that some native plant fanatics seem to want to turn back time. In the case of monarch butterflies, it almost seems like the monarchs have let down the side by adapting to tropical milkweed and using it to establish new breeding grounds.
“…let down the side”? Aren’t we all on the side of the monarchs?
Perhaps you feel some ideological commitment to their historic migration, which may not be necessary if monarchs can spend the winter in the warming climate in our temperate zone. Migration is very costly for animals. If they can be spared that drain on their resources, the species will benefit in the long run.
Also, the historic migration to Michoacan, Mexico is in great jeopardy because of timber operations. I visited that site about 25 years ago. It was an awesome experience, but I would trade it for survival of the monarch species. Wouldn’t you?
I didn’t realize that the spring beauty mining bee (Andrena erigeniae) or the yucca moth (Yucca moth (Tegeticula antithetica), among many other specialized insects, are red herrings. Silly me for caring about them.
I use mostly natives in my yard, initially because they survive best without supplemental water and only need some compost and don’t require specialized nutrients. Add in the benefits to other wildlife and for me it’s a no-brainer. BUT I give myself a dryish cottage garden where I can plant anything I think might survive, and I accept that given our human disruption of my little local micro ecosystem and overall climate change, strictly native plants won’t necessarily be the best fit for the current conditions. So noninvasive dry-loving plants from anywhere are slowly making their way into our yard, as long as they serve some kind of purpose (which can be simply an amazing show).
As an amateur gardener dealing with an overactive conscience, a limited budget, and limited energy to give the garden, this approach gives me both peace and joy.
Forty years ago I moved into an old house in Dallas where the flippers had applied glyphosate to a curtain of bamboo between two houses. Within 10 years my cat and my dog had died of gut cancers and within 15 years, I, too, had cancer. It’s anecdotal, I know, but I believe the cancers are related to the herbicide applied so heavily and broadly.
I’m sorry to hear about your pets, and more importantly, about your own cancer. As you state, your comments are anecdotal. I just want to point out that glyphosate breaks down in the soil as quickly as seven days, though more often a couple of months. And that is in the soil. Unless you are the one spraying it there is little danger of you ingesting it in any way, unless of course you eat the vegetation on which it was sprayed.
Aerial spraying of any pesticide is likely to drift. In the case of Dana Milbank, his aerial spraying from a drone ended up in his eyes. There have also been legal cases in which applicators of pesticide were sued because their spraying killed crops in neighboring properties. The plaintiffs won some of those cases.
Glyphosate causes cancer, remember “we destroy the village to save it” in Vietnam? Same misguided thinking. Zealotry is rarely nuanced.
Glyphosate was not used in Vietnam, but rather something called Agent Orange was. Agent Orange contained dioxin, which is far more toxic and remains in the soil far longer than glyphosate.
Glyphosate is a strange ‘ingredient’! And one to be avoided. Much of the commercial GMO seed is ‘Round-Up Ready’. What that means is that when sprayed on agricultural fields it kills the weeds but not the Corn, etc. However, the plant does take it up and therefore it does go into the food from that field. It doesn’t remain viable in the soil but in the food it is a horse of another color. Thus, we now have glyphosate in breast milk of women who do not live in areas where it is used, i.e. metropolitan areas mostly. How could it get there if not through foods?
I knew one of the three men who developed glyphosate and he assured me that I could drink it and not be harmed! I didn’t try it, but he died with 3 types of cancer, 2 that were new.
I read Susan’s post and all of the comments with great interest. I think of myself as a mostly native gardener but did an ‘audit’ of my garden this summer before I hosted a “Wild Ones” garden tour and discovered to my surprise that by species count (not biomass), my garden is only about 60% native. This fall my small back city garden has been alive with pollinators of all kinds on my native asters. I also planted single dahlias for the first time, and there have been so many bees that I have had trouble cutting the flowers to bring indoors. I give these details about my own garden to show that I am not a native plant absolutist.
That being said, I want to comment on tropical milkweed. My husband alerted me to a recent study by the University of Georgia (Andrew K. Davis, Jordan R. Croy, William E. Snyder. Dramatic recent declines in the size of monarch butterfly ( Danaus plexippus ) roosts during fall migration. Proceedings of the National Academy of Sciences, 2024; 121 (43) DOI: 10.1073/pnas.2410410121) that suggests that tropical milkweeds are contributing to the decline in the fall monarch migration. Nonnative milkweeds have longer growing seasons, and as a result these plants may lead to more monarchs becoming infected with a debilitating parasite because the infectious parasite spores can build up on their leaves. The study also suggests that captive rearing by well-meaning enthusiasts may be hurting more than helping. The final paper is not open -access but the pre-print is: https://www.preprints.org/manuscript/202405.1630/v1/download This study was also written about in Science Daily on October 16, 2024. More information to be considered……
Thanks for offering this study Pattie. Very helpful link. –MW
I am in 100 % agreement with this article.
I am treated like a disease if I mention non-natives! I am a PSU master gardener and former owner of a 4-Season container garden business owner. Native fever couldn’t be more present than here. Gardening is a love of ALL plants, shrubs, + trees… my beds are a community of both. I employ good garden practices of composting, little to no green grass ( even in my HOA! ) no till, low water requirements, matrix planting, successful four season interest, and so much more. Keep up this rant. More people need to hear this! I could never give up so many lobbies in my beds! Just like society, life is all about the mix!
Thank you + keep writing!
I love this post!
Thank you Susan, again for a most controversial post. In my most diligent search for native plants in the wild all over and many wild places in my area, I have been ultimately disappointed at the lack of diversity and being able to discover “native” plants I seek and would love to see in their natural environment. That said, I do buy native plants from plant sales and plant nurseries, but feel they are the exotics not the norm. As far as “native” how technical do you want to get? Native to the U.S., native to your section of the country, native to your state, your county, your town? Many insects and birds roam, migrate and venture outside their normal range thus becoming accidentals. They are in survival mode, using and taking advantage of whatever they can. Therefore any slashing, burning, and decimating with chemical warfare to eliminate unwanted growth is unproductive and abusive behavior. It flies in the face of any endeavor to save the sensitive workings of our natural world. Wherein lies the consideration for the mysteries of the complexities of nature that have yet to be explored and discovered? How do we, humans, become the end-all and be-all of decision making that impact species so diverse from our own, that may effect their welfare in ways we know nothing about? Thank God, if left to its own resources, nature will claw its way back to revive and flourish, look at Chernobyl.
Thank you so much Susan for making me aware of this podcast episode, which I listened to along with several other episodes. Karen is refreshing and completely curious, and that is a wonderful thing. Would that there were more like her! – MW