WHEN I READ the other day that Native Plant Trust, the nonprofit plant conservation organization in New England, had successfully raised the money to complete the endowment fund needed to save its region’s most imperiled native plants in a seed bank, it was like a silver lining kind of story.
Yes, the plight of natives in the region, like the state of native species in other regions around the country, is dire. Native Plant Trust estimates that “a staggering 17 percent of the region’s native plants are on the brink of extinction, with an additional 5 percent already lost.” But efforts like the seed bank offer hope—the silver lining I mentioned—and the seed bank is just one of the organization’s hopeful seed-focused projects.
I talked with Tim Johnson about those projects, and about how seed works to promote diversity and evolution, and why local seed is so important and more. Tim in January became chief executive officer at Native Plant Trust, which was founded almost 125 years ago as New England Wild Flower Society, the nation’s first plant conservation organization, and the only one solely focused on New England’s natives. He has an extensive background in environmental horticulture and biological science, and until recently, he led the Smith College Botanic Garden. (Above, collecting swamp milkweed seed, Asclepias incarnata; photo by Kate Stafford. Photo of Tim, below, by Sam Masinter.)
Read along as you listen to the Oct. 7, 2024 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on Apple Podcasts (iTunes) or Spotify (and browse my archive of podcasts here).
native seeds, with tim johnson
Margaret Roach: Congratulations on the successful fundraising to endow the seed bank.
Tim Johnson: Well, thank you. I really appreciate it. It’s good to be here with you. And we were very fortunate to have so many supporters of this project.
Margaret: Yes. So is this a big freezer somewhere? [Laughter.] What’s a seed bank? What is this seed bank?
Tim: That is right. If you were to see it at present, it may not look like a lot. We have a series of freezers which are held at Garden in the Woods. We also just built a brand new large walk-in freezer, which will be our offsite backup. So when we’re talking about seed conservation work, ideally you’re storing your material in two different locations, in case something bad happens at one of them.
Margaret: Yes, yes. And so just to give people … to sort of set the scene, I mentioned in the introduction just briefly, the state of native plants. I mean I remember not long ago speaking to a scientist who’s an expert in trilliums, native trilliums, and most of the trilliums in the world are in United States, or a lot of them are in this country. And he told me that a third of our native trillium species in the U.S. are threatened with extinction, for example. What’s under the most pressure? What are some of critical cases that are in the seed bank or that you’re hoping to get? And I mean, what are some of the species that are targeted, that you’re trying most urgently to look after?
Tim: So throughout New England there are 389 species which are considered globally rare, Division 1 species. These are the rarest plants in the world. And then we can look at Division 2 as well, which is several hundred more plants in New England. Our seed bank is focused on those Division 1 species. And then we’re starting to step a little bit into the Division 2. And so a couple of examples, some of the rarest species include Jesup’s milk-vetch [Astragalus robbinsii var. jesupii], this is a species we’ve been working with for a while now, not just on seed banking, but actually then using seeds for reintroduction. And so we’ve been able to bolster those populations because of the material in the seed bank. And thankfully through that work there’s actually been three new locations where the plant has been found because of reproduction that’s happening, not because of reintroduction. So that’s just one example of how we are using the seed bank, not just for storage, but also for reintroduction work. [Native Plant Trust photo, above, of bagged seed of maritime marsh elder.]
Margaret: So there are how many accessions, so to speak? How many species are right now in the bank? I’m sorry.
Tim: So what I said was that there are 389 globally rare species throughout New England. Right now in our seed bank we have 2,100 collections. There are actually 476 species. So we have some species beyond the globally rare.
Margaret: O.K., that’s where I didn’t understand the numbers. So there are some that aren’t on that rarest of the rare list, but that are also important and are in there. I see.
Tim: Yeah, that’s correct. So we have representatives from over 79 plant families. We added 85 collections and about 600,000 seeds in 2023 alone. And the goal is that we’re currently working to have representative samples from around 3,300 known what we call “elemental occurrences.” These are basically populations of the 389 globally rare species in New England.
Margaret: So seed: So if we backtrack when we think about seed, having one seed is not enough [laughter]. So how seed works—and I’m always fascinated by the mechanism of seed and how the process of setting seed, multiple seeds, enriches diversity, potential diversity, in subsequent generations and so forth. So tell us a little bit about seed. And I mean it’s obvious, but it’s also not so obvious why this is the most critical thing, this seed.
Tim: Yeah. So I am a seed nerd through and through. My background is as a-
Margaret: Had a feeling about that. Yeah, uh-huh. [Laughter.]
Tim: My background is in seed physiology. I really love working with seeds. I think about them as locks that we’re trying to pick or unlock. Going out and collecting seed is one thing, but then can we figure out what does the seed actually need so that we can store it long-term?
Some seed can be dried and frozen, some seed can’t be. And then we can take a step beyond that, which is, this seed, which is in what we call a quiescent state, it’s not dead, but it’s actually metabolizing. It’s waiting. It’s waiting for the right conditions. And sometimes those right conditions for germination are really simple. It’s just water. That’s our tomato seeds. They don’t need anything but temperatures somewhere between 50 and 100 degrees and they need to be wet. They don’t even need light to germinate. But other species can be really finicky and can have really complex dormancies.
And so just because we have the seed doesn’t even mean we can germinate it. So that’s another use of our seed bank, is actually using some of the seed to try and figure out how to germinate the seed.
You had asked about seeds and biodiversity, seeds are the sexual propagules of plants. So for anyone who’s a gardener, who’s ever done any sort of division, maybe you’re dividing up your salvias or your onions or you are planting clones of your strawberry cultivars, those plants are all genetically identical to each other. They don’t have any diversity between them.
Seeds carry—they’re siblings, they’re brothers and sisters—so they share a suite of genes, but they also have their own combinations. And this level of diversity is one of the ways that our ecosystems really resist significant change and they are able to continue to adapt and evolve as change is happening. [Above, collecting zig-zag goldenrod, Solidago flexicaulis; photo by Alexis Doshas.]
Margaret: Yeah, I mean those subtle…In one crop of seed from just one season of seed, from these open-pollinated, these straight species of plants or a particular plant, there will be subtle differences in the genetics, the traits, I guess, that are in there. And it can prove that some are going to be more adaptable to, because of course they’re alive as you’re saying, even though they’re sort of sleeping, they’re alive. So they’re adapted to certain conditions over the generations that that plant’s been grown in, and they carry those traits.
And it’s like you don’t know what’s going to be needed in the next generation and the one after that and the one after that. And there’s variability in the crop, and it’s a great thing. That variability is good, right? I mean they’re not all exactly identical.
Tim: That’s right. Diversity is the thing upon which evolution is acting. A species can’t change unless there’s a degree of difference within its population to start with. Because then as some plants thrive, perhaps because they’re more adapted to a drier climate or maybe they have more resistance to a new disease, they pass those genes onto their offspring. And so that breadth of diversity, it’s kind of like an artist working with the full suite of colors versus maybe trying to make a painting with just reds. So it’s a fuller scope of options.
You can’t have change happening unless there’s a great deal of diversity to start with.
Margaret: Yeah, it’s the secret weapon for survival.
Tim: It is the secret weapon, yes.
Margaret: It really is: to not be exactly identical. So the seed bank, and Native Plant Trust in general—from its foundation, from its founding more than a century ago—its regionality is critical. And there are organizations around the country doing other parallel efforts or similar efforts and whatever in those areas, specializing in those ecoregions or whatever. And regionality is really important, too, because local seed, particularly when we’re talking about native plants of an area, that’s another genetic thing.
That’s another thing that, it’s not just any old … I mean, some plants range from the East Coast to the Rockies in the northern half or two-thirds of the country. There are some species that are very widespread in many states, but they’re not all exactly the same as we were just talking about. And you might want the local ecotype for best results. So preserving local strains of seed is also important, yes?
Tim: Absolutely. One of the examples I think about a lot is redbud, Cercis canadensis. This is a species that’s naturally occurring from Florida to Canada. And if we were to look at how these plants at these different locations respond to the changing light, the way that our days get shorter and longer over the course of a year, it’s not the same from between Canada and Florida. Or we think about their ability to survive in the winters. Florida winters are much milder than Canadian winters.
And if we start to move these plants around, not only will they not probably perform as well, I don’t really want … Nothing against Florida. I just don’t want a Florida redbud in my yard in Massachusetts; it’s probably not going to make it. It’s got thin blood. But we also, if we were to continually bring plants from different regions into our region, you could end up sending those genetics into your local ecosystems.
Now, in a lot of cases, it probably won’t matter. There’s a concept of genetic swamping, and so this rare individual is likely to have its genes swamped by the locals. But especially when we start to think about restoration-scale work, where we might be operating at acres or tens of acres or hundreds of acres, ideally the plant material that we’re using in those efforts is adapted to that ecosystem. They’re both going to perform better, and they’re going to be better integrated into the wider genetics of the region.
Margaret: And so besides the seed-bank effort, Native Plant Trust, I think, is also collaborating with other institutions regionally on a project called Northeast Seed Network. And I think it says on the website that’s to grow native plants in seed-producing gardens to be used in ecological restoration projects and by nurseries, to grow plants for sale. So to try to meet the growing demand within this ecoregion for the natives of this region. And so this is another project.
Tim: This is another project. It’s one of the projects I am most excited about. Northeast Seed Network was developed in partnership with Ecological Health Network. There are now several hundred people who are involved in the initiative, who all share this goal, which is that not only should we have a sustainable supply of native plant seed, but that we need a network of growers, retailers, and seed brokers who are ensuring that that seed is adapted to the different ecoregions of New England.
Our contribution, Native Plant Trust’s contribution, is this project we’re working on called, right now, called the Seed Hub. We actually need a better, more descriptive name [laughter], but we’re starting to pilot the production of seed, and in doing so, figuring out how do we actually clean it, what are our yield’s going to be per acre. And then the next phase is to start to work with farmers to actually do production, and then to bring that seed to the market.
One of the things I really love about this work is how connected it is to our local economies. So farmers, especially small farmers, diversified revenue is now the norm rather than the exception. There’s a lot of excitement right now around land easements for things like pollinator strips. There’s a lot of excitement about what’s called agrivoltaic. So combining agricultural techniques with solar energy production. Imagine if those pollinator strips or that agrivoltaic system, that agrivoltaic field, could actually be another cash crop, in that it’s producing seed that can be cleaned and sold to people who are doing restorations or for the production of nursery plants in the region. It’s a very noble circle. [Above, Native Plant Trust’s seed-processing building; photo by Aileen Bellwood.]
Margaret: Right, because the demand now—you have caught people’s attention. Organizations like yourselves have caught people’s attention with the importance of planting, devoting some of their landscapes to natives and so forth. And the demand, however, has exceeded the supply when it comes to that locally sourced seed.
We’re still often relying on the wonderful and incredible nurseries, many of them in the Midwest, who have been at it a long time, the sources who… the great nurseries who have been doing this since when you could barely sell this stuff, but they believed in it. You know what I mean? They’ve been at it a long time, but there’s not those nurseries all over the place to get our fill-in-the-blank plant, our Rudbeckia, and our whatever, our little bluestem and our this or that. There’s just not, or there hasn’t been. So it’s very exciting that there’s this, I think, is Cornell involved in the Northeast Seed Network and other institutions?
Tim: There are many institutions. It’s growing daily. I can’t even keep track of all the organizations that are evolved. But you’re right, it’s kind of like the dog that caught the car [laughter]. We’ve now gotten the word out there. There’s so much demand. The other thing I’ll note is that at the restoration scale, this shortage of seed has been known for 20 years. Figuring out how do you actually bring this, not only are we … We’re not just trying to bring seed to market. We’re actually trying to stand up an industry that doesn’t exist. And that’s a big challenge. It’s a wonderful challenge. I’m sure we’re going to figure it out. And that between the various partners in the Northeast Seed Network, we will build this robust network of seed producers and plant producers. But it’s a bit of a challenge right now.
Margaret: And then of course, Native Plant Trust also like at Nasami Farm, one of your properties, you propagate plants and you sell plants, and you have a consumer-facing nursery operation and other things going on there. So you are doing this work with seed, with native seed, on a lot of different levels, yes?
Tim: That’s absolutely right. I think seed is probably the most recognizable resource that we’re working with, day in and day out. So whether it’s doing specialty collection for state partners and federal partners who are struggling to source material, whether it’s seed banking for rare plants, whether it’s production that’s happening for sales, whether it’s production that’s happening for reintroductions into wild populations, we spend a lot of time thinking about and talking about seed. [Above, planting a seed plot at Nasami Farm; photo by Jane Roy Brown.]
Margaret: So you said, you confessed, that you’re a seed nerd [laughter]. Does that mean that at this time, probably some of your staff… because this is a time of year in New England where you are located, that some of the native meadow flowers, for instance, are beginning to set seed and so forth, and harvest times will be coming along in the next weeks and even months. Are you collecting seed or are you and your colleagues, are your colleagues out collecting seed? Is that a big part of the sort of fourth quarter of the year activity for some of the staff?
Tim: You’ve nailed it. We have a-
Margaret: I bet you’re all running around. [Laughter.] With baggies, little bags.
Tim: Yes, we have a seed of seed collectors that are working on a couple of projects with the Forest Service. We have harvests coming in from our pilot plot that we have established at Nasami Farm. We have bags of acorns and hickories coming in that are being collected. I will also note, collected with permission. We’re very, very stringent about written permission for the material that we’re collecting.
And yeah, I think it’s fascinating when I look at this seed, how much of a story it actually tells. It tells us when it’s ready to be harvested. Because the state that it comes to us in, it gives us clues about how we should be processing it. It might tell us a little bit about how to store it. And then I’m always … Just can’t help, again because I am a seed geek, I look at them and see them as living things. They are effectively babies, waiting for the right conditions, waiting for us to unlock them or waiting to be unlocked by nature. And there’s a whole story being told by every one of these seeds.
Margaret: I know that you are less than a year, I think, at this position. So I don’t know if you moved or whatever. Do you have a garden that you’re making, and is seed sowing a big part of making that place, or any personal seed stories to share?
Tim: Yeah, I’m always playing with seed. I like figuring out how to germinate it. And I often tease, I really like plants when they’re really little. Sometimes I get a little bit bored as they get bigger. But I’ve got a project right now trying to do some lawn conversion, brought in prairie dropseed, not from seed, but from some plugs because it’s really difficult to germinate actually [laughter]. I’m struggling to grow it from seed.
This last year I put a couple of species of native anemone into my garden that I grew from seed. That, I think, took me two or three years to figure out how to get it to grow. I’m always playing with something. Sometimes it makes it into the garden and sometimes it doesn’t. I’ve got a little bluestem, you just mentioned little bluestem. I’ve been growing little bluestem from seed and transplanting it into this lawn conversion that I’m doing. And it’s just always a thrill anytime we can figure out how to make something grow.
Margaret: Yeah, I mean with the figuring out, sort of unlocking the secret of each species, what it needs to germinate, I have sometimes looked at the … There’s some reference material on the website of the Wild Seed Project up in Maine, Heather McCargo‘s project. I don’t know if you guys have some of that, too, where it sort of categorizes different species by whether it needs cold stratification, or it needs warm, cold, whatever. Or it needs to be sown fresh, or it needs to be whatever treatments, pretreatments, like scarification. And I’m always fascinated by that. Who figured all that out? [Laughter.] Do you have any references that you use? Do you go to the reference books or something or just experiment? [Above, spring in the propagation greenhouse at Nasami Farm; photo by Alexis Doshas.]
Tim: There are, well, yeah. So oftentimes going to colleagues and asking what has worked or what has not worked. There are also instances where Native Plant Trust staff have put in the time to figure out how to grow plants. A great example of that is work with Robbins’ cinquefoil [Potentilla robbinsiana]. This was a species that in the nineties was actually on the endangered species list. Native Plant Trust figured out how to store, germinate seed, propagate plants, and then began reintroducing the plants onto Mount Washington [in New Hampshire]. And eventually the populations grew large enough that the species was delisted. So our staff are doing a lot of that research themselves.
Another project that I am really excited that Native Plant Trust worked on and figured out how to germinate, Pennsylvania sedge, Carex pensylvanica. I actually learned that Native Plant Trust knew how to do this before I worked at Native Plant Trust because I had reached out to the people here and said, “Hey, I’m trying to figure out how to germinate this, and do you have any seed?” And they said, “Not only can we give you seed, but we can tell you how to germinate it.”
So that research project was quickly wrapped up because Native Plant Trust had figured out how to … This species generally has very low germination when it’s freshly harvested, around like 3 percent. And our staff have figured out how to get that up to over 90 percent. So that means that now when people are growing Carex pensylvanica for nursery production, they don’t have to do vegetative division. We can actually grow it from seed and again, maintain that genetic diversity.
Margaret: So I was just curious, anything else you want to tell us about the seed bank project? Is there a next step? Is there something now that you’ve completed the fundraise, is there a next step that’s happening?
Tim: There are always next steps.
Margaret: I bet [laughter].
Tim: So in the short term, the next steps really look like how do we expand our capacity in the seed bank to store, not just what are called orthodox seeds. These are seeds that you can dry down and because you can dry them, you can freeze them.
Margaret: Right.
Tim: There’s a whole other group of species which are called recalcitrant. They cannot be dried down. And because you can’t get the water out of them, you can’t freeze them. And so for recalcitrant species, we need to look at alternative methods of ex-situ seed conservation. This might be storage in liquid nitrogen, it might be tissue culture where we’re actually maintaining genetic lines rather than seed. It may be arboreta, for example; we may actually have to grow plants, entire plants or entire trees.
Margaret: Wow.
Tim: So that is something we’re starting to explore. Many of our ferns, many of our orchids, are difficult to store conventionally, and so we need to build some more facilities so that we can actually do that storage as well.
Margaret: Well, brave new world. Thank you ,Tim Johnson. And again, congratulations. Thank you for making time today to talk. I do appreciate it, and I’m so glad to speak to you again, seed nerd, that you are [laughter].
Tim: Always a pleasure. Yes, thank you. I appreciate it.
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MY WEEKLY public-radio show, rated a “top-5 garden podcast” by “The Guardian” newspaper in the UK, began its 15th year in March 2024. It’s produced at Robin Hood Radio, the smallest NPR station in the nation. Listen locally in the Hudson Valley (NY)-Berkshires (MA)-Litchfield Hills (CT) Mondays at 8:30 AM Eastern, rerun at 8:30 Saturdays. Or play the Oct. 7, 2024 show using the player near the top of this transcript. You can subscribe to all future editions on iTunes/Apple Podcasts or Spotify (and browse my archive of podcasts here).
