Ep 215. The Tiny Wonder of Duckweed

After last week's episode about Nature Sounds from My Porch Camp, Mary Stone describes photos received from Blaine Rothauser. One, a Green Frog peeking through a patch of Duckweed, the smallest flowering plant. She shares the wonders of the unusual tiny aquatic plant, its benefits to wildlife and humans, and its rapid growth. Plus, what to do if it covers your pond. 

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Related Podcasts and Posts You'll Enjoy: 

The Tiny Wonder of Duckweed - Blog Post to come

Ep.214. Nature Sounds from My Porch Camp

Nature Sounds from My Porch Camp - A blog post featuring Blaine Rothauser's stunning photos.

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Mary Stone, Columnist & Garden Designer
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Welcome to Garden Dilemmas, Delights, and Discoveries.

It's not only about gardens; it's about nature's inspirations, about grasping the glories of the world around us, gathering what we learned from mother nature, and carrying these lessons into our garden of life. So, let's jump in in the spirit of learning from each other. We have lots to talk about.

Thanks for tuning in, Mary Stone
Garden Dilemmas? AskMaryStone.com
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Transcript

 Ep 215. The Tiny Wonder of Duckweed

Sat, Aug 02, 2025 11:10PM • 10:49

SUMMARY KEYWORDS

Duckweed, green frogs, nature sounds, great horned owl, pond ecosystem, aquatic plant, biomass, protein source, waste water treatment, algae blooms, green manure, garden dilemmas, natural history, ecologist, clonal budding.

SPEAKERS

Mary Stone

Mary Stone  00:00

Mary stone, Hello, fellow lovers of all things green. I'm Mary Stone, and welcome to Garden Dilemmas, Delights and Discoveries. It's not only about gardens. It's about nature's inspirations, about grasping the glories of the world around us, gathering what we learn from Mother Nature, and carrying these lessons into our garden of life. So let's jump in, in the spirit of learning from each other, we have lots to talk about. 

Mary Stone  00:26

Hello there. Welcome to this screen porch. I'm out here early because I'm trying to beat the cicadas that start screaming. It is getting to be such a loud chorus during the day, and then at night, there are the night singers. So I'm out here early, and I think you'll hear some green frogs in the background, hopefully. Speaking of singing, thanks to those who reached back after our last chat about nature sounds from my porch camp, Blaine kindly sent photos of green frogs and great horned owls. And if you didn't click through to the blog site, I encourage you to do so, because there are artful photos that he had sent. One of these three frog friends that is so adorable, it is a showstopper. No kidding, I'll put the link in the show notes so you can take a look at it. And then another photo is of adorable frog eyes peeking through green growth that inspired this week's story about duckweed, the smallest flowering plant I look forward to sharing. But first, I have to tell you about last night's camp. It was a bit before midnight, and I heard the calls of the great horned owl, so I quickly went to record it from my phone. But of course, I didn't have my podcast mic on the porch with me, so there was another critter in the chorus that I couldn't identify amongst the hoots of the great horned owl in the Nighttime Chorus of garden insects we spoke about in Episode 177 It doesn't sound like an animal in distress, but I wonder If any of you can identify this other singer. So, if you know who the singer is, please reach out to me by emailing me at ask marystone@gmail.com.

Mary Stone  02:17

 I have to tell you, I did some googling research to see if it was a red fox sound. And when I was listening to the sounds of red fox, they make so many screaming sounds that are rather, oh, I don't even know how to say it's alarming to hear it wasn't that sound. But anyway, Jolee went crazy when I was listening to the different sounds. So I'm going to count on you to see what you come up with. Anyway, on to this week's story that starts like this. 

Mary Stone  02:45

Hello, fellow lovers of all things green. Last week, I shared the sights and sounds of a campout on my screen porch, including the chorus of green frogs that lulled me to sleep. My friend Blaine Rothheiser, a natural history photographer, ecologist, and rare species biologist, sent extraordinary photos, one of them a stunning trio of green frog friends. Another is the eyes of a green frog peeking through tiny leaves that turned out to be duckweed. It grows in our pond every year, but I never examined what it was. I thought it might be an undesirable fungus. After significant rainfall, the pond overflows into the Johnsonburg Creek, clearing much of it, and while it always grows back, there's plenty of life taking advantage of the pond. So I concluded it's nothing to worry about. 

Mary Stone  03:35

I have a funny memory from years ago of a black bear emerging when Miss Ellie and I were on our way over to the footbridge to cross over the pond. It was a late, overly hot September day, and as we were approaching the bridge, he came out of the pond. Looks at me like like I was interrupting his bath. He shook off what I thought was algae, and as the stuff flew, I said out loud, Shall I hand you a towel? Off Bubba Bear ran it was a funny moment. 

Mary Stone  04:08

After receiving Blaine's photo, I dug further to learn about duckweed and found that there are more benefits than harm to this unique floating aquatic plant. In fact, it's sold for use in ponds and aquariums. Native to most of the United States and Canada, and living in freshwater ponds and lakes all over the world., This remarkable plant is on the US Forest Service's website as a plant of the week. They write that common duckweed, Lemna minor, is the smallest flowering plant known. Each plant is merely a quarter inch, a tiny leaf, officially, a modified stem that floats on top of slow-moving ponds and lakes. It's true from a distance, it looks like, you know, I want to say pond scum, but that sounds nasty. It's this lovely green swath on top of the pond that doesn't even look like leaves. But it is really tiny, tiny little leaves all gathered together, so beautiful. 

Mary Stone  05:04

While walking over the footbridge yesterday, I noticed swathes of white amongst the green and wondered if they were in bloom. It turns out that duckweed's white flowers are so tiny that they are barely visible. They rarely bloom, and therefore are hardly ever seen. Duckweed primarily reproduces through clonal budding, an asexual reproduction process where a new plant develops from an outgrowth of a bud of the parent plant. Perhaps the white swaths I saw were the sun's reflection on the tiny leaves. Is was gone later that day.

Mary Stone  05:38

The US Forest Service writes that the flowers consist of two microscopic staminate flowers and one tiny pistillate flower in a pouch-like sack. Yet, as tiny as they are, they attract flies, small spiders, mites, and even bees. Now this is the remarkable part. Common duckweed can duplicate its biomass every two to four days and cover the body of water when conditions are right, which is warm temperatures between 50 and 90 degrees in part shade to full sun. But that would be indirect sunlight. They don't like to be in the hot sun. That's, you know, blasting onto the top of a lake or pond. And they prefer nutrient-rich, slow-moving water. So there you go. All those things are good benefits about my pond, which, when I moved here, I was very nervous, because I think I've told you before that it's like a dam for the runoff of the mountain stream that comes down here and feeds the creek on which I live. And so when I first saw the house, it was snow-covered. And then it was April 1, I'll never forget. And of course, the snow had melted, and I realized it's this, it's a dam. There's this concrete dam that contains the water until it overflows into the creek. So it is always slowly moving and quickly moving during big storm events. 

Mary Stone  06:58

I should probably define biomass. So I looked it up. It refers to the total mass of the organic material produced by plants that includes all the living and recently dead plant matter, such as the stems, the leaves, the roots, and even dead plant material like leaf litter and wood when you're talking about large woody plants. So, essentially, it's the total weight of plant material within a defined area or ecosystem. So there you go. So they are speedy spreaders, every two to four days, duplicating their biomass. 

Mary Stone  07:30

Maybe some people think that the green cover of duckweed is unsightly, but this green, by and large, is good. Duckweed provides shelter and food for fish, ducks, aquatic life, as well as food for livestock, and is also a source of protein for humans. Already used in food in other parts of the world, manufacturers are looking into ways to include duckweed in protein shakes, pasta snacks, and baked goods. So it's true, the livestock drink the water and they're getting a protein boost at the same time. Other benefits include purifying wastewater by removing excess nitrogen and phosphorus, as well as cleaning out heavy metals. In Devils Lake, North Dakota, their wastewater treatment facility uses duckweed for the final treatment of wastewater before discharging it into Creole Bay. This all-natural system can treat approximately 3.5 million gallons of wastewater per day during the warmer months. So, isn't that amazing to use a natural thing that Mother Nature created for us to clean the water? Duckweed can also impede the growth of harmful algae blooms, plus it helps keep the water cool. 

Mary Stone  08:37

However, there is a concern that if duckweed fully covers a pond or lake, it can overshadow other plants, hindering photosynthesis and potentially impacting oxygen levels in the water. And admittedly, I prefer some of the water visible in my pond. But the remedy is as simple as using a pool skimmer to remove some of the duckweed, being careful not to take any frogs or fish with it, and then you can spread it as green manure in the garden to enhance the soil, a beautiful thing. Indeed, green is good. Garden Dilemmas? AskMaryStone.com.

Mary Stone  09:15

So as we're wrapping up here, I'm hearing the lovely sound of a slight little drizzle that's starting. I think we're going to have some significant rain today. Rain today. A cold front is coming in to give us relief from these day upon day, amazing heat and humidity that we've had, 95 degrees, 98 one day when I was out tending to a garden. So I am looking forward to a cooler spell to come. That's one thing about nature and its cycles during hard times, there's always a shift that occurs after bringing the glory of nature into our lives, all the beauty, all the sounds. I hope you take time to enjoy them all. I sure enjoy our time together. And I want to thank you for joining me. And I want to ask you, too, if you have not subscribed to the podcast. Podcast. Please do so, and if you feel so inclined, I would appreciate a five-star rating and share it with a friend or two; so more can join us in learning in this garden of life. Enjoy the day, smile at all the beauty and the sounds. I look forward to the next time on the screen porch.

Mary Stone  10:19

You can follow Garden Dilemmas on Facebook or online at GardenDilemmas.com and on Instagram at the hashtag. Mary Elaine Stone. Garden Dilemmas, Delights and Discoveries is produced by Alex Bartling. Thanks for coming by. I look forward to chatting again from my screen porch, and always remember to embrace the unexpected in this garden of life, have a great day.