Coneflower with a bee
Image by Tim Kennelty

Learn about perennials with Nature Calls: Conversations from the Hudson Valley

Episode Nine: Perennials

Get ready for planting season with a informative and wide-ranging discussion about perennial plants with Joe Behn from Behn's Best Perennials. Learn about the wide range of options available to add color and interest to your landscape. Monarda and Japanese Stiltgrass are the focus of the Good Plant/Bad Plant segment with Tim Kennelty.  And Wooly Bears are the star of Hits and Myths with Devon Russ.

Hosts: Tim Kennelty and Jean Thomas

Guest:  Joseph Behn

Photo by: Tim Kennelty


Perennials (Joe Behn)Behn’s Best Perennials (

Good Plant/Bad Plant (Tim Kennelty)


Japanese Stiltgrass: 

Hits and Myths (Devon Russ): 


Perennials (Joe Behn) / Good Plant -- Bad Plant / Hits and Myths

Welcome to Nature Calls: Conversations from the Hudson Valley. Our team's goal is to present science based information about gardening and all things nature in New York's Hudson Valley. Hosts Jean and Tim, along with team members, Teresa and Linda, are Master Gardener Volunteers for New York's Columbia and Greene counties. So if you're interested in gardening or nature or nuggets of information about what's happening outside your door, settle in, enjoy the conversation. Whatever the season, we have something to say.

Musical segue

Tim: Hi, I'm Tim Kennelty. Hi, I'm Jean Thomas, and welcome to another edition of Nature Calls: Conversations from the Hudson Valley. We have an exciting guest today, one of our favorite people, right, Joe Behnpain from Behn's Best Perennials.

Jean: He's a wholesale grower, so you can't go to his place. But you can go to any of the retailers that he supplies.

Tim: And it's the perfect time of year because it's officially Spring, right? It's officially Spring. So we're really going to start thinking about planting perennials. Yeah, Joe is really a perennial expert. So we're going to talk to him all about his favorites and how he grows them and what's really a durable perennial and native perennials and all that good stuff.

Jean: Joe knows more than anybody I know about perennials. In fact, he's even taught some of the Master Gardener classes and is always very generous to the Master Gardeners.

Tim: And also in this episode, we have another edition of my Good Plant/Bad Plant.

Jean: So today's topics are Monarda and Stilt grass.

Tim: Yeah, you probably have Monarda and Stilt grass in your property.

Jean: No doubt. I like them both, unfortunately.

Tim: Oh, that's bad. That's bad. Menarda is like one of my favorite plants because it's in the mid family so nobody eats it. It's an amazing pollinator plant, and the hummingbirds love it as well.

Jean: I have a hummingbird that comes to my house and visits one particular Monarda flower in front of my porch and I sit and watch him go from one little floret to another.

Tim: And then the bad plant is Japanese Stilt grass which some people don't even know they have it, but it's a really bad invasive plant. So hopefully people will learn a little bit about that as well.

Jean: Yeah, it's another one of those seductive, sneak-in kind of invasive,

Tim: It does sneak in. The seeds sneak in on the tires of lawnmowers and on cars. I always say know your foe as far as invasives, so this is one you really want to know about. Also, in this episode is another edition of Hits and Myths. I love Hits and Myths because I always think that some of these things are true. And some of them are not. It's about the woolly bear caterpillar.

Jean: The famous woolly bear, everybody is an expert on them. Yeah. And they will come racing to you and announce that because of whatever it's doing that week. It has predicted the weather.

Tim: And the question is does it predict the weather? I don't even think weathermen can predict the weather. So I don't know about woolly bears.

Jean: This edition also goes into the actual life cycle of the woolly bear and its other phases.

Tim: Yeah, I've always wondered about that. So I think this is gonna be a really great one.

Jean: I'm looking forward to it.

Musical segue

Jean: We're here with Joe Behn, owner of Behn's Best Perennials, a wholesale perennial plant nursery in Malden Bridge, Columbia County. Joe's been very generous with the Master Gardener Volunteer program. Over the years, he's taught classes on perennials to the trainees, and he sold us plants at wholesale prices for our plant sales and even donated plants from time to time. Welcome, Joe. It's a pleasure to spend some time with you. Thanks for coming in. To help us learn more about perennials, let's start with a little history. You started your nursery in Malden Bridge in 1988. Is that right?

Joe: That's right.

Jean: Okay, tell us a little about yourself and the nursery.

Joe: Thank you for having me. I actually grew up in the agricultural business, my family, George and Louise and my sister Nancy and I bought a dairy farm in Malden Bridge, which is really where the nursery still exists back in 1963. So it was raised in agriculture. And so everybody get their feet on the floor at 5:30 in the morning to do milking and all that stuff. And so they milked the farm from '63 to July of '69. And they sold the farm off on that side of the street and we moved over to what would be the eastern side of Route 66. And that's where my nursery is today. But yeah, so just lots of livestock and agriculture. And then I slid over into the plant business, which is a little bit more easily maintained than livestock.

Jean: Why did you choose perennials?

Joe: Perennials have always been kind of suited to my personality, busy in the spring, summer in the fall, and then completely relaxed in the winter. That lifestyle was kind of my lifestyle. And then as you study plants, trees, shrubs, lichens, whatever it might be, you realize that all these plants are beautiful, and they're completely in sync with what's my own life.

Tim: I'm happy it's a beauty thing, Joe. And it's not just about your lifestyle, do you would have like feet of clay?

Joe: It definitely is a beauty thing. There's no question.

Tim: But it's a wholesale business. You don't sell retail. Right?

Joe: Exactly right. We're a wholesale. So we're farm to the landscape trade, who then install into homeowners.

Tim: So you're usually dealing with landscape designers and people, actually?

Joe: Yep, extensive plant lists. People come and pick up with their trailers and trucks.

Tim: So when I come into your nursery, there are so many perennials, how many perennials Do you have? Do you usually grow?

Joe: I think right now we're about 480 types and normal inventory runs somewhere between 21,000 and 28,000.

Tim: Wow, that's amazing.

Joe: And it's interesting that the sales and the production basically are almost the same. So that number actually never changes. We don't ever plummet down to real low or extremely high. It's this is natural balance that...

Tim: But there's there's times that certain plants are available and certain plants are not right?

Joe: Exactly. Yep. If we run out of something many times you can't replace it until you know the following year.

Tim: And is that because of how you grow from seed? Do you grow from plugs, like what what's your usual method?

Joe: It really depends on the individual plant. But many times there's an ideal starting point for most things, and a finishing point. And you really can't change those two things too much. There's a little bit of wiggle room. Other plants you can do three or four times a year and just keep recycling them in if they're really fast. Salvias are a really good example. Although salvia is you can do them the last day of March, you could do them every six or eight weeks.

Tim: And if you're heavy planting season is what like, February, March, April?

Joe: We plant from probably the last couple of days of March, right through October, there's not a week that goes by the or day that goes by that we're not.

Jean: Do you do more plugs and see.

Joe: So we do plants from our own seed in that one small greenhouse as much as we can. A lot of things come easily from seed, and then everything else that's cuttings will purchase, but comes in as a plug.

Jean: Right.

Joe: And then also bare roots, in Spring time. Yep, there's a certain point where when you get into the middle of late May you want to be done with your bare roots have those inputs, and then we can do bare roots again, when we get into September, where it's cools off a little bit where they can root in and have good success that way.

Tim: And do you collect your own seat? Or do you basically you're buying seed?

Joe: Oh sure, yeah, that's some of the fun, there's certain things you can collect pretty easily from plants that have in my house, plants at the nursery, plants on side of the road.

Tim: Like, what kinds of plants do you collect the seed of?

Joe: A bunch of native things...

Tim: Coneflowers or ah...

Joe: No, I don't collect any coneflowers. We purchase all of those because the seed has to be exactly true. Yeah, there's a whole host of things. Rudbeckias, asters from the side of the road. Eupatorium hyssopifolium, Heterotheca villosa, which is really hard to find.

Jean: What is that?

Joe: Heterotheca is actually a golden Aster, a good four and a half feet tall.

Jean: Oh, ok. And does it look like a golden rod to the casual eye?

Joe: It looks like an aster that's completely yellow.

Jean: I gotta make a note.

Tim: I got some there. It's super rugged, right?

Joe: Right. Yeah.

Tim: So when I drive along the county roads and I see a crazy person picking seed, that's you, right?

Joe: Probably there's a lot of crazy people out there. But in the fall, I do carry a pair of scissors and paper bags in my car.

Jean: Okay, so here's the question. Do you keep all your seeds in a candy box or canning jar? Things like that?

Jean: Oh, sure. Yeah, you know, they get cleaned and sorted, labeled.

Jean: Oh, I don't do that.

Joe: And put in the fridge.

Joe: Oh, yeah, I do that with a lot of them.

Joe: You do need to label them as to what they are. Because you think you'll remember what this is. And so the date you collect it, and what it is, that's really all you need.

Tim: How do you even sort through what you're going to plan what you're going to buy, like how do you decide what's on your list?

Joe: That's what we do in the middle of winter. And of course, over the course of the year, all my landscape customers, gardeners are coming and going, and we're having conversations and many times they'll go like, Oh, you need to grow this today. It's really great. I love it ...

Jean: Fashion.

Joe: I can't find it. Yes, it's very fashion. And so I learned to take those notes. Just really quick, scribble it down, pin it back on the board.

Tim: So there's kind of "in" plants, plants that are in this year.

Joe: Sure. Yeah.

Tim: So what's the most requested? Do you have, I want to know what it is? Is there something that people been going crazy over this year or just a bunch of different things?

Jean: It's a real broad spectrum? I can't think of anything off the top of my head. I have to go through my notes.

Tim: Yeah, yeah.

Joe: Cuz it's really overwhelming as to how much stuff comes in.

Tim: I know I've been trying to convince Joe to plant more Goldenrod solidago, and he's just resistant.

Jean: Well I can understand that.

Tim: It's a great plant.

Jean: And has it become, has it become a noxious weed in England where they grow it on purpose. It can be really aggressive.

Tim: Yeah, there are different types but I'm gonna just defend Goldenrod here.

Jean: Fine.

Tim: There's many, many varieties of it that are great.

Joe: Of course it has to sell.

Tim: Right. Oh, that little thing.

Joe: Like if you buy three plants, I'm gonna have 100 of and then those are the 97 sitting, become weedy.

Tim: And I want to know how you keep everything watered in the summer, because that must be huge challenge.

Joe: This last year was super easy because it rained every third or fourth day, not so much that it was a real problem. But we have an automatic irrigation system. And now three different zones. And it clicks on every other day. Runs from two in the morning till six in the morning. I get there, I never see it turned on.

Tim: Oh, so you don't do hand water as well?

Joe: Oh, sure, especially in brand new things.

Jean: Oh, the babies.

Joe: Yeah, once the baby goes to pot. And then, you know, and then it's usually on a wagon. So it's got to get watered, and then we park it off someplace and they just they root in three or four weeks out there on the wagon. So you have to go back to the wagons because we don't have irrigation out there. And once it's ready, once it's full, then it goes into nursery. It's it's kind of finished product.

Jean: So it's the pre-nursery nursery.

Joe: There you go. You got it, great.

Tim: And you probably have more people working with you in the summer than say at this time of year. Right?

Joe: Yeah, exactly. Nobody's here with me now. But Spring time, Spring time just six or 7 of us plus myself. And then in the summer, they kind of all dispersed out into other jobs. And I'll usually run the place with just myself and two people who stay.

Tim: And of course your dogs right. The dogs are famous. Because the mascots

Joe: Ginger was the original. Yeah, she's original Corgi. And now we've got those two terrorists, Johnny and June. So we're building a pen for them because they are too rambunctious.

Tim: See, this is the reason why go to Joe's place.

Jean: Oh corgi was worth the trip from anywhere. Well, now Ginger is famous. She's been immortalized in our cookbook, got the Ginger Soup.

Tim: Let me ask you something. I always wonder at the end of the year, I know you have kind of a sale at the end of the year. But do you overwinter some of your plants?

Joe: Oh, my goodness. Yes. Yeah. Yeah, we're probably sitting on about, I would say somewhere north of 21,000. We never, it never drops below, count around that figure.

Tim: And, and how do you, how do you do that? How do you overwintered?

Joe: So you know, it's basically just like in your garden, everything gets cut back. In this case, it's in pots, they all get pushed together and into these beds to concrete block in configuration with with ground cover under it. And so they all get put together, they all get counted. And then it's a microfoam overwintering blanket gets put on top, and then two layers of white plastic. So it's this little short bed that's about 10 inches tall, 10 feet wide by 60 feet long.

Tim: And do you lose plants in the spring? I mean...

Joe: The only time we lose plants is really from the rodents. There's three things out there, the moles of holes in the field mice. They're all active all winter, which I still can't believe you know, everything else seems to hibernate. Why not you guys? Yeah, but they are out there and they're looking for a ...

Tim: And they eat the entire plant? Or they just ...

Joe: It's it's really funny, I've learned now to all depending on the exact plant, but many times they'll tunnel in from the bottom and just eat the root system, but the crown will still be there. So it's a mess. And it doesn't happen often. But you can kind of just pick the plants out, pick the crowns out, clean it and just re-pot and just reset the plug back in there and it'll re-root. So you really don't lose the plant. You just have...

Jean: You lose time.

Joe: Yeah, you need to be really as efficient as you can with your time.

Tim: Have you found that there are more gardeners and you have more activity with COVID?

Joe: COVID really jumped things. I think the first year, which would have been what, 2020? We went up 30%.

Tim: Just because more people are out in their gardens?

Joe: Exactly. All these people that never garden before, or most of them hiring gardeners.

Jean: Yeah.

Joe: They weren't necessarily doing it themselves. But it just, it was quite a surprise.

Jean: Yeah. Now this brings a question to mind that we should have asked earlier on. Let's do a definition of a perennial. We're happily chortling and talking about perennials, but our listeners don't necessarily know what the definition is.

Joe: Sure. Yeah. So perennials. It's kind of easy. It's your lawn, your lawns a perennial. My dad used to joke that all these ornamental flowering plants are just educated weeds.

Jean: It's true. That's a great definition.

Joe: It really, really kind of nails it. They're just educated weeds and perennials are plants that die down to the ground and come back next spring.

Tim: Some are woody and some are not, right?

Joe: Right. Most everything we grow, almost everything, is herbaceous. So that means that they're dying right to the top of the ground. And all their life buds and so forth are sitting there ready to go.

Tim: So you have these amazing plants are incredibly healthy. And if I were out there and I wanted to buy your plants, I'd have to have a garden designer, right, or go to a plant sale, because I know you sell to a lot of ...

Joe: Exactly.

Tim: Not for profits, and people like us when we had plant sales, right?

Joe: Yep, the Master Gardener programs -- in all the counties around us -- and garden clubs, a lot of garden clubs, the Garden Club of America folks.

Tim: Right, right.

Joe: So there's quite a few. And that's almost all springtime, it's really spring heavy.

Jean: Oh sure, for the sales.

Joe: The month of May is nutty, as far as those deliveries to plant sales or picks up.

Jean: But now every little plant has a tag in it. And you do a great job on that. When I go to one of the big box stores, if I'm lucky, there's a tag in and, if I'm really lucky, it's the right tag. So your information in your plants, those pots have absolutely vital information?

Joe: Right, especially the tags that we can make in-house. So when I sit down at the computer, I can, I can do the text and try and hit on...

Jean: So it's geared for us, locally.

Joe: Exactly.

Jean: It makes a big difference.

Joe: Exactly.

Jean: Yeah.

Tim: If I'm a new gardener, and I'm thinking about making a perennial mad, that's something that you would use, obviously, as a tool. But do you have any other advice for like if I'm a gardener, and I want to start with some really easy perennials, like what's your advice? What do you think of easiest perennial? So basic top 10?

Joe: It really depends on what you like. Now with the internet, you can find so much so quickly. It's and it's still the same old thing is its garden catalogs, and maybe what you grew up with what you recognize colors and certain things like that.

Tim: But what what are you telling the most of what are people coming in and ask for? I need to know the trends.

Joe: It's almost all things that are in bloom, right. And it's phlox paniculata, when phlox paniculata's in bloom. Or it's phlox subulata when, you know, it's April and May people are flocking to your door for because they see it in their neighbors or wherever they're seeing things. And it's just a progression. So that question is almost impossible to answer. It changes that day, week to week.

Tim: I know when we had plant sales, we go to chose and pick what's blooming because people just don't want to buy something that's on bloom, right?

Joe: Exactly.

Tim: What about deer resistant plants? I mean, did you get a lot of questions about that all the time?

Joe: Yeah. And I used to kind of have a sort of list, you know, way back in college. So my college was I went to BCC over in Pittsfield. Second, I took a skip year out of high school and studied environmental sciences. And that's when I learned that all of these things have names, which I never had actually realized that every plant has has a name. And then a couple of years after that, I went to Farmingdale for horticulture and then off to Cornell for two more years after that. So what I learned, I think at Farmingdale, was that deer resistant plants are still ferns, ornamental grasses and silver foliage plants. And after that, there is no rule, right? They, they eat whatever is...

Jean: The ate my peonies one year.

Joe: Yes. I think a lot of times it's the little ones as, as mama you know, the little, you know, mom and two or thre, are going around your yard, the little ones are taste testing. Exactly.

Tim: But what about like mints?

Joe: Well, we're fenced off right? We have a seven foot fence around the whole place because whatever they're not eating, they're walking on.

Jean: Yes.

Joe: It's so they leave their mark behind, you know, so I gotta clean that up. It never fails, so...

Tim: Linke mountain mint or bee balm or something like that. They never seem to touch in my garden, but I don't know if you've found people tell you that they do.

Joe: Tim, I rarely grow plants outside my nursery, so I don't have the expertise as to what happens in a garden that's completely open. And it's difficult, but there's there's all those things, It's the, it's the rabbits. It's yhe woodchucks. It's the deer, right? It's your neighbor's dog. It's you know, it's constantly...

Jean: It's a jungle out there.

Tim: What do you do about that?

Joe: You just keep planting is what happens...

Jean: Joe likes that we just keep buying new plants.

Joe: You have that moment of where you want to scream and it's like, alright, let's just grow something else or...

Tim: And what about shade versus sun plants? I know you've, you've a lot of shade plants like you have a lot of heurichas and a lot of beautiful shade plants. I mean, do you find that a lot of people come in and designers looking to do shade gardens?

Joe: Very nuch. Especially dry shade. So it's ferns, epimediums, hellebores ...

Jean: I adore epimediums.

Joe: Oh, yeah, and there's so many.

Jean: And they want to be daffodils. When you look at the plant flowers really close, they're just so cool.

Joe: I've seen a couple of that are really pushing their flowering more than the foliage. So I think we're gonna find some really, really good epimediums that will kind of wow you more.


My list is getting really long over here Joe.

Joe: They kind of wow you more because they're so soft. They're so subtle.

Tim: Well, and, and I know that you have garden designers come in and ask you for specific plants. But are you like in the winter looking at, oh, this is the epimedium. This is the new one that's out there. And that I mean, so you're making a catalog.

Joe: Sometimes it might be, you can see it this year, but it may not be available - you know, in the pipeline as far as propagation, so you kind of have to keep that notation, and then eventually it'll pop up on somebody's list somewhere. A propagator that's grown it where you can buy it in, in volume.

Tim: And I know, you know, I'm kind of a crazy person about planting natives, and I know that you have a big selection of different native plants. Are you getting a call for that? Is that something that's trending?

Joe: My goodness, yes. Yeah, we got dragged down that road about 10 years ago, where people come in looking for goldenrods and I'm like, you must be out of your mind. Because it's everywhere. But they want to specific ones, ones that are maybe a little more ornamental, white ones, and so forth. Asters, of course, have gone through the roof

Tim: Phlox, right.

Joe: Oh sure.

Tim: Yeah. And, and I know you have a lot of different coneflowers and a lot of different beebalm.

Joe: It's been, I wouldn't say difficult, but unusual that for so many years, like you know, you go through hort school, you learn to grow all these cultivated things, cultivars of this that and the next thing. And then the native thing came back and like they don't want this echinacea that's, you know, cultivated frost and fancy colors. They want the original. So now you have to go back and grow the orginal plants.

Tim: Kind of the straight plant. Yeah, right. Because they've done so much kind of somersaulting in their hybridizing that they've kind of hybridized out the pollen and all of that, right?

Joe: In some cases. Yeah, sure, yeah. Again, we have to talk about actual specifics. Yeah, okay-of plants.

Jean: What kind of percentage do you think of your plant stock now is more natives or native-ish?

Joe: We try to use the term improved natives. Yeah, those things are all good pollinators. They still set seed, the birds still eat them. Yet it's not the exact plant that that we started with 30 years ago. But the percentage, it's hard to say, you know, maybe 30%.

Tim: Yeah, that's in the nursery that's what I would guess. Yeah. I mean, there's I mean, you really have a big selection of natives

Joe: And that helps a lot.

Tim: Yeah, yeah. And I mean, you don't you don't necessarily identify them as natives. I noticed like at the big box stores, they don't either, they just have those plants, maybe, as opposed to specialty nurseries that do, right?

Joe: Yeah, there are nurseries that do nothing but native plants. And that definition is a little bit wonky. When was it a native? Where's your starting point? What's your definition thereof? But...

Tim: I'm encouraged by that, that people area starting to ... Yeah. Oh, absolutely.

Joe: Yeah. Oh, absolutely.

Tim: Yeah, and designers as well. There's some specific designers that that really focus on that.

Joe: Right, exactly.

Tim: So, one of the big issues that we have in this county are the Asian jumping worms, and I know your plants never have them. I don't know, how do you kind of guard against that? What do you do about that?

Joe: So all of our soil comes in and composted, heated to a certain degree. We get it from McEnroe organic down in Millerton, New York. So it comes in free of any of that, and then they go into pots, and then the pots are on the ground cover. Right. So there's really they never actually touched the Earth itself.

Tim: That's really important. Right, right.

Joe: Yeah, yeah. I realized the crazy worm is the problem.

Tim: And people have been asking you about it, I'm sure right. Yes. Yep. So I think that...

Joe: I have had landscapers come in and physically dump out 20 pots to check for worms. Wow. And I will tell them, like, alright, go ahead. You have a good time. You're not gonna find any, but you know, hopefully you don't find them.

Tim: The way you're growing, it's kind of impossible for you to have them, and that's really important for the nursery industry, right?

Joe: Probably never impossible, but certainly the percentage is very, very, very low.

Tim: Right

Jean: So you can't casually bring in a load of topsoil or a load of anything, you have to be very careful. And it has to be, you have to know that it's been sterilized in some form.

Joe: Right. You're like, yeah, if we bring in like a 10 yard load of double grind mulch. Yeah. Which we use for my home around the nursery. It's always dumped on a tarp, underneath, and then covered on all, physically, on all four sides.

Tim: Yeah. Well, and speaking of kind of ecologically minded, I know one of the things you do which I think is great as you do pot recycling. So as folks can bring in their pots, I know I've done this, and and you do reuse a lot of them, right?

Joe: Absolutely. Just knock the soils out of them. In that case, it's not soil again, it's these composted mixes. If something is really dirty, it goes on to recycling, but we reuse pots up until they're broken. This last year, last two years now, getting pots because of the supply chain and COVID and so forth - huge increased demands.

Tim: I know that you don't sell retail. But you do have the famous wagon, right? The roadside plant wagon. Yeah, tell us so people can come and buy plants.

Joe: And so somewhere along late April, when things start to really warm to have some cold hearty vegetables that are ready, and of course, ground pholx and other sorts of things that are in bloom, we have a 8 by 16 hay wagon. We loaded up with plants pull down the edge of the road, and people drop the money in the box. And there's a little parking space and I can kind of see the wagon from my nursery and we used to see people coming and going all day. It took a while. But now it's really become kind of famous destination. Yeah. Wonderful. Every week it's different stuff. Great. Yeah. All the way through April through, I think the last time we had it is almost the first of November was when I pulled it up for the last time.

Tim: So stop by the wagon.

Jean: If you can find Malden...

Joe: Malden Bridge.

Jean: Malden Bridge - then you can find the wagon.

Tim: So that sounds like a great stopping point for us. What do you think Jean? Do you have any more questions?

Jean: I have 1000 more questions.

Tim: You do.

Jean: But we filled all the time we have and it's always a delight.

Tim: Thanks so much for taking your time and joining us Joe.

Joe: This has been fun.

Jean: Thanks, Joe.

You're listening to Nature Calls: Conversations from the Hudson Valley.

Stay tuned for Good Plant/Bad Plant

Tim: Welcome to Good Plant/Bad Plant, a recurring segment of this podcast that will focus on two plants per episode, one that supports pollinators, birds and other animals, and one plant or plant group that is invasive or noxious weed, thus, good plant/bad plant. I'm your host, Master Gardener Volunteer, Tim Kennelty. So with our premiere episode, I'd be remiss in not talking about what Doug Tallamy that native plant guru calls the most powerful plant, the mighty oak. And when I say oak, I'm talking about the genus Quercus. And I'm really referring to oaks that are native to our area like white oaks, red oaks, swamp white oaks, Scarlet oaks, and a few others. Oaks can grow to about 100 feet and can live from 200 to 400 years. Red oaks and Scarlet oaks and pin oaks have a fibrous root system, and they're fairly easy to transplant, but white oaks have a taproot, and they're best planted wood saplings.

Tim: Oaks are generally relatively easy to grow and thrive in well-drained acidic soil in full sun. They're really beautiful, majestic trees, often with attractive fall foliage in shades of red, gold, and orange. So why are oak so important to the ecosystem? First and foremost, they're what Tallamy calls keystone species, one that defines an entire ecosystem, particularly in supporting insects that are subsequently consumed by birds. Oaks support more than 500 different caterpillar species, which, of course, turn into butterflies and moths but are critical food for young birds as well. They're also great at sequestering carbon and pumping that carbon back into the soil. And they produce acorns that are eaten by squirrels, deer, turkey and other birds. I could go on and on about oaks, but suffice it to say, if you're going to plant one tree in your yard, and you really want to support wildlife, you really can't go wrong by planting an oak.

Tim: So now to our bad plant, boo hiss. As the oak may be the king of beneficial plants, I'm counting the queen of invasives, Japanese knotweed. Knotweed is a member of the buckwheat family, and like many invasive plants, it was introduced as an exotic ornamental from Asia in the 1800s. And by the 1930s, it was already recognized as a problematic past. It can grow from three to 15 feet and has bamboo-like stems. It's even referred to commonly as Japanese bamboo. Knotweed can thrive in disturbed areas like drainage ditches, wetlands, streams, woodland edges, and along roadsides. It spreads rapidly through underground rhizomes. In fact, a single piece of rhizome that breaks off can easily create a new plant and add to the spread. Knotweed can be devastating to the environment as it forms dense stands that crowd out and shade native vegetation. Large stands or monocultures of knotweed reduce species diversity adversely impacting ecosystems and wildlife. A dense stand of knotweed can also contribute to soil erosion. As for identification during Spring, reddish purple shoots appear from a network of spreading rhizomes and developed into asparagus-like spears that grow very rapidly. By early Summer, the stems are hollow with purple speckles, and the leaves alternate along each stem with a zigzag pattern. In late Summer, distinctive creamy colored spike-like flowers emerge that are quite beautiful actually. Knotweed control, and control not elimination, is what we're going for as a practical objective with this invasive species can be a multi-year project focusing on reducing the rhizome network. Management includes repeated cutting, and most likely will require herbicide application. For more information on identification and control of knotweed, I'm going to include some really good trusted links and sources. It's always better to know your foe.

Tim: So that's a wrap for today's edition of Good Plant/Bad Plant. And remember, as gardeners we really can make a difference. If you want to support birds, butterflies and bees, include native plants in your garden, and watch out for those invasives.

You're listening to Nature Calls: Conversations from the Hudson Valley.

Stay tuned for Hits and Myths.

Jean: Welcome back to another episode of Hits and Myths. Have you heard people say something like, look at that woolly bear: such broad bands of black; that means we're in for a tough Winter? I have. The cute, fuzzy woolly bear caterpillars grow up to be Isabella Tiger moths, an orange moth with a fuzzy leaf and small black spots on its wings and body. All butterflies and moths spend some time as caterpillars before becoming adult butterflies or moths. A quick detour: what makes butterflies different from moths? It's not really a scientific distinction but a popular one. They're all members of the same scientific grouping, the order Lepidoptera. We tend to love the colorful ones who flit about during the day and are much less familiar with those who are active at night. So in general, butterflies have larger, brightly colored wings and fly in the day. Moths are duller and fuzzier, have wings that are smaller compared to the thicker bodies and fly at night. Also, butterflies often rest with their wings folded up so they touch. Moths tend to rest with their wings open to the sides. All butterflies and moths go through a metamorphosis when the caterpillar makes a cocoon or chrysalis about itself. And while the animal is inside, it changes from caterpillar to moth or butterfly, including growing wings. The silkworm, which is a moth caterpillar, not a worm, secretes the fiber to make its cocoon entirely from its own body. People turn that into silk. Other moths use bits of leaves or other stuff to help build their cocoons, and some do their metamorphosis underground.

Jean: The woolly bears have two generations each year. Some hatch from their eggs in May and some in August. The caterpillars eat many kinds of leaves, including some garden plants, some weeds and some true leaves. Woolly bears do all of their eating while they're caterpillars; the Isabella Tiger moths do not eat. In the fall, the caterpillars look for a sheltered space to hibernate like a gap in a rock pile. That's why you most often see them in the fall: they're on the move looking for a good spot. They hibernate as caterpillars, not in cocoons. They make their own antifreeze and will almost freeze solid. When spring comes, the woolly bears come out of their winter spots and make their cocoons. Inside the cocoon they do their big transformation. When it leaves the cocoon as a moth, it has a short life remaining. The moths use their wings to find mates and lay eggs.

Jean: So, can they predict the weather? It's a nice story, but nah. How can we be sure? There are a few reasons. First, there's lots of color variation between caterpillars. If you collected a bunch of woolly bears, you might see some with wide black bands and some with narrow black bands, but they're all going into the same winter. Second, the colors on each caterpillar changes as it eats different food, but they eat many kinds of plants, so the kind of color change is happening all the time for woolly bears. Woolly bears who are close neighbors might be changing foods in ways that make for opposite changes in color. Third, there are closely related species that are much more black or much more brown. So looking at those would throw off the prediction. Fourth, and possibly most important, the woolly bears predicting weather myth is itself kind of woolly. Some version say more black means a colder winter. Some say just the opposite. And some say sort of related things like, caterpillars that are woollier are preparing for a colder Winter. Basically, no one really wants to pin this down. It's just a fun superstition that's not meant to be taken seriously. We'll find another myth for the next time around.

That concludes another episode of Nature Calls: Conversations from the Hudson Valley. We would like to thank Sandra Linnell and Devin Connolly from Cornell Cooperative Extension of Columbia and Greene Counties for production support. And a special thank you to our listeners for joining us on this episode of Nature Calls: Conversations from the Hudson Valley. You can find links to any of the topics mentioned in this episode at our website at Comments and suggestions for future topics may be directed to us at or on the CCE Master Gardener Volunteers of Columbia and Greene County's Facebook page. For more information about Cornell Cooperative Extension of Columbia and Greene counties, visit our website at or visit us in Hudson or in Acra. Cornell Cooperative Extension provides equal programming and employment opportunities


Last updated May 3, 2023