RATHER THAN digging in, let’s wade into our topic this week—because the subject is water lilies. If you follow any botanical gardens on social media, you’ve probably seen how the giant tropical Victoria water lilies, with their massive pads, have gone viral in recent summers thanks to a competition called the Water Lily Weigh-Off that tests how much weight those ingeniously designed leaves can bear without sinking.

One participant, New York Botanical Garden in the Bronx, has been cultivating and stewarding and showing off these dramatic plants since long before the virtual rivalry began. Marc Hachadourian, Director of Glasshouse Horticulture there and also a leading expert on orchids, is here to tell us about both the tropical and hardy species in NYBG’s collection—and what all the fuss is about—and also some of the secrets of how aquatic plants work, anyhow. The story of the water lily is a fascinating one, whether you grow them or not.

NYBG is currently staging an exhibit called Flower Power, and a display of tropical water lilies outside the conservatory is just one part of that show.

Read along as you listen to the Aug. 17, 2026 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).

miraculous water lilies, with marc hachadourian

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Margaret Roach: Hi, Marc, and welcome back to the program. You’ve got a few water lilies going on [laughter].

Marc Hachadourian: Yeah, just a few. It’s that time of year. Despite us kind of wilting in the hot weather we’re having here in the Northeast, the tropical water lilies absolutely love it.

Margaret: Yeah. So how long has NYBG been growing water lilies, do you think? And I just want to get a little history, because specifically then also, what is it, Nymphaea amazonica? Is that what the Amazon water lily is called that’s the star of the water lily way off that I was talking about in the introduction.

Marc: Yes. The genus Victoria, the big sisters of the classic kind of Monet-type water lilies native to the Amazon Rivers Basin and its tributaries in South America, is really the star of the Weigh-Off.

But when it comes to the cultivation of these plants, the New York Botanical Garden has been growing water lilies for a very, very long time. The central courtyards in the historic Enid A. Haupt Conservatory have always contained pools full of Nymphaea water lilies, both tropical and hardy varieties [pool of hardy varieties at NYBG, below]. And there are some wonderful historic photographs of the conservatory in its early years with the pools full of blooms. Even cultivating the Victoria amazonica itself is something that’s been done here from the early days of the conservatory, in which we have historic photos where the Victoria was grown on the inside of the greenhouse, not like the outside where we do it today. And so in previous iterations of designs of the conservatory, the amazonica water lilies were grown indoors. But nowadays we grow them outdoors in our conservatory courtyards, where they get all of the sunlight warmth that they require to attain those massive pads that everyone is fascinated with.

Margaret: Because after all, there’s going to be a Weigh-Off [laughter].

Marc: Oh, yes.

Margaret: We want to be competitive. So alongside the lotus, I guess, which I think might be part of your plantings, too, or probably is, the water lily also has sort of the traditional spiritual history a little bit, Buddhist, etc. You see some of these beautiful, big aquatic plants represented in very old artworks.

Marc: Yes. The relationship between human cultures, spirituality and religions and aquatic plants is a very long one. Many people know about the reference between the lotus and Buddhism and many Eastern religions. But when it comes to the relationships with water lilies, it is also very tied to… Many of our people know the early references in Egyptian mythologies in which the flooding of the Nile River helped return the abundant not only wildlife, but also the flora found in that region in which many of these aquatic plants, which are many water lilies, returned from the mud—in which the symbolism of a water lily, sort of this bit of rebirth, the idea of growing in a very unusual environment is something that’s carried throughout history in a number of different cultures throughout the world.

Margaret: So these biggest of the big, the amazonica ones, as their name suggests, I think, they’re from the Amazon Basin. But I think there’s water lilies native to every continent except Antarctica. Antarctica always is the one that’s the “except” when you’re naming plants [laughter].

Marc: Well, what’s funny about that is you often hear that term used about “native to everywhere except Antarctica,” whether it’s orchids or water lilies. And in reality, the reason why, obviously, as we know, Antarctica is not exactly the most friendly climate to plants, but there are only two flowering plants native to Antarctica. Everything else there is a lower plant, like mosses.

But when it comes to the genus Nymphaea or the Victoria, the Nymphaeaceae, which is a very interesting plant family, is actually also a very ancient one that has been around for a very, very long time. Which gives clues to its distribution around the world in which it’s found in mostly slow-moving waters throughout the tropics and temperate climates in a number of different forms—all somewhat similar, but a group of plants that has more in common with magnolias than it does many modern plants.

Margaret: Interesting. Well, they certainly both have elegant flowers; magnolias and water lilies both certainly have elegant flowers, I would say.

Marc: But when it comes to water lilies and their diversity, you have here in the Northeast United States, we have our Nymphaea odorata, the common white water lily, which also crosses the pond and which you have in Northern Europe. Of course, a suite of tropical water lilies native to Central and Southern Africa, ranging throughout Asia, and even into an incredible group of water lilies, some of the largest-flowered Nymphaea, native to ponds and slow-moving waterways in Australia, which are some of the most beautiful of the genus Nymphaea. And sometimes the most difficult to study, because they often inhabit the same ponds as saltwater crocodiles.

Margaret: Oh, dear. [Laughter.]

Marc: Yes. I have to say, I admire the people who study Australian water lilies for their bravery, but I’ll keep my distance and deal with the spiny Victorias from South America any day.

Margaret: Right. So there’s a diversity of species within the genus and within the family. But morphologically, structurally or their engineering: I mean, aquatic plants always kind of amaze me just because of course as a gardener—a terrestrial gardener for the most part, although I do have a couple of water gardens, but not a lot of vegetation in them—we think of, oh, we have to have soil that’s fast-draining, and so the roots won’t rot, and there’ll be air and all those kinds of things [laughter]. But of course, this is a whole different story.

So what are some of the features, having worked with these plants so much, what are some of the features? And then dot, dot, dot, the big guys [laughter]: I mean, how in the world do they keep the leaves…? I mean, I’ve read estimates, everything from 6 feet across maximum to 7 feet to 10 feet to however many feet across that the Amazonica can get, the pads, the leaves.

But at any rate, I just wondered about, well, are these rhizomes, are all water lilies? Do they grow from rhizomes? Maybe we should start at the bottom.

Marc: So I think when it comes to aquatic plants and water lilies themselves, I think one of the fascinations is they are a bit of a mystery because they grow a little bit beyond our perception, submerged in the water where you’re really not sure quite what’s going on down there. But whether you’re dealing with some of the miniature tiny little species native to Africa or these Amazonian giants, this family all grows very, very similar.

The plants are not just a collection of floating leaves just perched on the surface, but emerge from the soil, the mud, at the bottom of a pond, sending their leaves up from usually very stout or thickened rhizomes to the surface of the water where the leaves then are presented towards the sun, getting access to light and oxygen. There are even a few water lilies that complete their life cycle below the surface of the water, where their leaves remain submerged and only the flowers pierce the surface of the water.

But when it comes to water lilies in general, they grow much like you would think about a bearded iris in which there’s a creeping rhizome producing an abundance of leaves and then flowers throughout the growing season. The leaves can even come up from almost 8 to 10 feet deep for some of our native species in which they can become very, very strong in terms of their growth.

But for water lilies themselves, they’re generally found in very slow-moving water—still water usually best, because it has to do with how they breathe. All plants like water lilies have stomata, pores that they breathe through and there’s a part of photosynthesis. And with water lilies, those pores, as you might suspect, are only on the upper surface of the leaves really. So as a result, the leaves cannot be disturbed too much with water or else it’s functionally, sometimes, the plants can almost drown.

But the leaves of some varieties can exist under the water in which they change the shape of their leaves to be able to absorb nutrients and oxygen through the water itself like other submerged aquatic plants.

But from these rhizomes, the leaves climb to the surface where they get all that wonderful sunlight available that they need to photosynthesize. And then the plants will, in most cases, continually produce blooms throughout their season. The buds will develop and emerge from the surface of the water, in which the blooms will last typically about three to four days. And for a day-blooming water lily, the flowers will open about 9 or 10 in the morning and close just in the evening and repeat that for a couple of days, in which hopefully they’ll get pollinated. And if they do, they will then sink below the surface of the water.

But throughout the season, the plants continually produce blooms, whether it be a day bloomer, or in the case of the Victoria and a few other relatives, they are night bloomers. They open their flowers at sunset and they close just as the light returns the next morning.

Margaret: Right. The thing that I find about the Victoria types, I mean, when you look at detailed pictures of those lily pads, those leaves, as I said before, it’s like a real feat of engineering. I mean, for it to support itself there. I mean, first of all, what’s its purpose? Its purpose is to be able to sustain the plant to perform photosynthesis and so forth and stay afloat to take in all that light and so forth. But they have almost like the edge around or the lip like a bowl, like a pot. Do you know what I mean? It’s not just a flat leaf floating on top, it’s a real 3D kind of thing and the underneath, I don’t know if it’s venation or what you would call it, but it’s really supported, isn’t it? It’s quite intricate how it’s made so strong, the engineering.

Marc: When it comes to plants, as you’d imagine, I have a few favorites [laughter], but when it comes to my few favorites, the Victoria water lily is always ranking very, very high.

They are absolutely some of the most fascinating plants, and I think one of the plants that really spawned my interest in botanical horticulture, coming to see them here when I was very, very young. And like many of our visitors, you turn the corner and you look and admire the beautiful water lilies, and then you see the Victorias.

And the first thing that crosses your mind is: What is that? Because the water lilies, in some ways, they look like a perennial or a plant. They seem something familiar about them. But when you see those enormous floating platter-like leaves of Victoria, we even have visitors don’t realize that they’re real. They think that there’s some sort of sculptural element we added to the pool or some functional element. But in reality, they are individual leaves of this giant of the water lily world.

The plants have one of the fastest growth rates of any plant out there in which they germinate from a seed about the size of a pea. And then in a matter of months achieve these monstrous statures in which leaves on Victoria amazonica can be several feet in diameter, 6, 7, 8 feet. And the largest leaves recorded belong to a newly described species of Victoria, Victoria boliviana, in which the leaves were almost a little bit over 10 feet in diameter, which is startling to think about a single leaf, a round leaf, being 10 feet in diameter with these upturned edges.

Thankfully, one of the things that I think many of our visitors don’t even realize is that Victorias, I kind of joke, have a little bit of anger issues, in which they are covered with an armature of spines on the underside of the leaves, the stems, essentially everywhere except the flower petals, roots, and upper surface of the leaves. They are armed and dangerous and well-defended.

Margaret: So is that anti-herbivory? I mean, is that anti-predation so to speak?

Marc: Yeah, you wouldn’t exactly want to chew on one of those leaves because those spines are quite strong. They’ll go right through a pair of rubber waders if you hit them wrong. But the spines I’m sure are protection against herbivory, but they also, I think, serve a secondary function. Where the Amazon water lilies are native to, these warm tropical and sometimes subtropical waters, the flood levels raise and lower throughout the seasons with rainfall patterns. And so when the waters return, these plants have to germinate and grow in a very rapid fashion to be able to reach maturity, bloom, get pollinated, make seeds, and then distribute those seeds before those waters recede and sometimes seasonally disappear.

And so this enormously fast growth rate they have, and those leaves have a function. Not only do they function like giant solar collectors, allowing this plant to grow at a rapid rate—the bigger the solar collector, the more energy and more food you can manufacture—but as those leaves unfurl, they unroll from the center outwards. And it’s believed that not only do they help push the leaves and other aquatic plants away, kind of clearing a space on the surface of the water, but those thorns help them almost as they unfurl, climb over other things, assuring this plant its place in the sun as it grows so rapidly.

So from a single seed the size of a pea in one summer, you can have a plant that could be almost 20 feet in diameter from leaf tip to leaf tip. And despite them looking like they’re individual floating platters, they are connected through petioles down to the root systems in which these massive systems of roots draw up nutrients from the soil in which Victorias are very heavy feeders. They love a fertilizer, both in their native environment where they would use the rich soils that are left behind from flooding rivers or in cultivation where they do appreciate a generous amount of food to get these enormous leaves growing in the summer.

Once they reach a certain size, they start flowering and they put up these enormous buds that are just about the size of a large grapefruit, which are armored with spines in the exterior. And the blooms are night blooming. So when the flower opens at sunset the first day, it is a bright white and tremendously fragrant. You can smell ours just from the edge of the pool, many feet away. The fragrance smells like an overripe pineapple. It’s wonderful.

And what’s also remarkable is like a few other flowers like skunk cabbage or the famous very smelly Amorphophallus titanum, the Victoria water lily will also undergo thermogenesis, in which it generates its own heat to help disperse that fragrance into the night air. And so if you take one of those heat cameras, you can actually see the difference in temperature between the surrounding air and the flower, which can almost be, I think, up to 10 degrees Celsius different.

And if you get your fingers down into the bloom, if you’re going to pollinate them, you can actually feel the warmth on the inside of the bloom, which is kind of remarkable [laughter].

Margaret: So I mean, when you said solar collectors, I thought to myself, “Oh, I wonder if the person who invented solar panels looked at a water lily.” Do you know what I mean? Because that’s a great image, right? I mean the thought of that’s exactly what those big things floating there are doing. It’s like, wow.

Marc: I mean, the ultimate solar panels and solar efficiency, solar power is really plants before we even –

Margaret: But the way these big, like the Amazonica, the biggest of the water lily, that pad just being there, you know what I mean, is very much like a solar panel. I mean, it’s there. It’s doing its work.

Marc: It is there.

Margaret: Whenever there’s light, it’s undeniable. It’s doing its work.

Marc: Its presence is undeniable.

But we’ll step away from the pollination of the plant for a moment. We’re back on the leaves. And these enormous leaves to get this diameters they need to achieve, as you mentioned earlier, have this incredible network of veins on the undersides of the leaves. These veins are raised almost 2 inches in which they create almost this kind of stained glass-like pattern. And this armature of veins are full of tiny, air-filled cells. Not only do they provide structural support for the enormous leaf, they also provide buoyancy and help the leaf stay afloat.

So that structural support, as legend has it, inspired famous glasshouse horticulturists to reverse engineer and give them inspiration for the construction of glasshouses and how to support the weight of glass across a roof structure. I’ve seen it mentioned anecdotally a number of places, but still have no definitive proof that that’s the case.

Margaret: Yeah, funny.

Marc: But it does make for a nice story.

Margaret: So I think Denver Botanic Garden started the Weigh-Off competition in 2022. I wanted to talk a little bit about that. And if I’m remembering correctly, as I said, I think it was 2022. And the weighing happens soon. We’re recording this on Aug. 7, and I think it’s in another week or something you’re going to be weighing and other institutions are going to be weighing theirs and submit the results. And last year, I think the top three entries were in the 170 to low 180-pound range that the leaves could support. It was incredible.

Marc: Absolutely. You are correct on those details.

Margaret: It was crazy.

Marc: You see a lot of funny Victorian-era photographs of people standing on the leaves, which is a bit of photographic trickery almost, in which not only do we know that the plants can support these weights. Last year’s record was 183 pounds. So this isn’t little kids floating on the leaves. These are full-grown adults.

But those Victorian photographs, I’m sure they were supported with armatures underneath. But when it comes to the current weights, I’ve seen photographs. If the weight is kind of distributed across the surface of the leaf—people will put a piece of plexiglass or a board on there—I’ve seen full-grown adults, granted rather skinny ones, in some cases, standing and being supported by the weight by the leaf itself, which is incredible.

This whole competition, this friendly competition, did get started in 2022 in which Denver Botanic Garden, who got this sort of inspirational idea, reached out to other gardens and said, “Hey, let’s have some fun and create a little competition, which we kind of see whose water lilies can hold the most weight.”

And I think post-pandemic, in a world where people were looking for uplifting stories and something fun, and of course social media being the perfect platform for this type of fun competition for people to root along and learn about these incredible plants and people having a lot of fun with this, it turned into an absolute phenomenon, to where when we joined the competition early on, our videos received over one and a half million views.

Where you do this and you’re kind of laughing your way through and you put it out there into the universe, virtual universe, and you say, “Well, I hope it does something.” And the next thing you know, the numbers kept climbing and climbing and climbing and climbing. And the public response to this has been wonderful.

Not only has it just been hysterically funny, in which some of the people who compete, even though they know they’re not going to win, they enjoy it and they’ve put up some really entertaining videos. So now people raise the bar every year in which they’ve created everything from “Star Wars” parodies, mad-scientist videos, and all sorts of content creation that goes along with it, not only to promote, to sort of celebrate their Weigh-Off, but also to teach people about this amazing plant. [A 2025 video from Royal Botanic Gardens, Kew, below.]

Margaret: Yes. I mean, I’m fascinated. And the great thing is that, well, I’ll obviously give information about how people can visit and so forth and the competition in general. But also you have on the New York Botanical Garden website, you have some how-to information on growing hardy water lilies as well in our water gardens, how we can do that, and how you grow the tropical ones as well as the hardy ones. So I can give links to all that how-to stuff, which is kind of fun because some of them, it says on your website, can grow as far north as zones 3 or 4.

Marc: Granted, most people may not have a garden pond where you do have enough room to grow one of these Amazonian giants.

Margaret: No, no.

Marc: But when it comes to water gardening, the best and really only requirement is a little bit of sun and water, which you can grow a diversity of beautiful water lilies in containers. And even a friend of mine sent me, and I love this picture, a person in Queens here in the borough of New York City, growing a lotus and flowering it in a five-gallon bucket on their balcony. So as you know, where it becomes to gardeners, where there’s a will, there’s a way.

Margaret: Yes.

Marc: And so to grow and bloom your own water lilies, it doesn’t take much.

Margaret: Well, thank you so much, Mark Hachadorian from New York Botanical Garden, for talking to me today. We’ve run out of time, but I will talk to you again soon, I hope. And thank you. Thank you.

Marc: You’re very welcome, Margaret. It is always great chatting with you, and I look forward to our next conversation.

(All photos courtesy of NYBG.)

more on water lilies

• 2025 Weigh-Off competitors with links to their videos
• visit NYBG’s Flower Power show
• Hardy lotus and water lilies for small ponds

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MY WEEKLY public-radio show, rated a “top-5 garden podcast” by “The Guardian” newspaper in the UK, began its 17th year in March 2026. 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 Aug. 17, 2026 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).