Gardening Unplugged - Solomon's Seal in the Garden

Gardening Unplugged - Solomon's Seal in the Garden

with Tony Avent

By Published September 07, 2022

Shop for Polygonatum at Plant Delights Nursery

Take a walk with Tony Avent and guests as he discusses one of our favorite woodland perennials, Solomon's seal. This chat is part of our Gardening Unplugged series provided free to the public during our Open Nursery and Garden Days. This chat was recorded May, 2018.

Other perennials mentioned by Tony in this video:


Video Transcription

I'd like to welcome everybody to Plant Delights and Juniper Level Botanic Gardens for our unplugged garden series. Today our topic is Solomon's seal. So, I'm assuming everybody's familiar with Solomon's seal - yes? no? Okay, a little bit. Solomon's seal is a woodland perennial native to both the US and Asia and Europe so it's pretty much a circumpolar group. It consists of five different genera plants. So, it consists of polygonatums, which is the most commonly used ones. Smilacinas, which are often called False Solomon's seals. Disporum, just like a little short Solomon's seal. Disporopsis, which is the evergreen version of disporum, and uvularia. Now, it's really interesting how plants get grouped and through the years people have grouped... The plants get grouped into families. So, you're related to you your first cousins you all get grouped together.

Polygonatums are actually in the asparagus family, which is rather interesting. Now also in the asparagus family are a couple other favorite plants of ours. Agaves are first cousin to Solomon's seal and hostas are all in the asparagus family. And so, they kicked a lot of plants out. They all used to be together in the lily family and they sort of split that up. It's fascinating that agaves and Solomon's seals are that closely related, sort of an interesting bit of trivia.

Okay, the most common group that the majority people know are polygonatums and in the U.S. we have, depending on your taxonomist, three polygonatums that are native, especially here in the East. But, as I mentioned, they're from also around the world.

This is a Polygonatum arisanense. This is one we've collected about an hour north of Taipei, in Taiwan, so this is, as far as we know, the first plant of this brought into the U.S. It is absolutely one of the most spectacular plants we grow. You would not think something from an hour north of Taipei would be hardy here but yet, it's sailed through this winter and every winter since we've had it. Solomon's seals range in size from two inches to over six feet. This is Polygonatum martini. This is one of the tallest species. This is an Asian species and this one can easily reach five to six feet, so it's a, it's really, really huge. If we walk behind us, this one has just finished flowering. So, all the polygonatums have flowers that hang down from the stems. This is actually one that we collected in Korea just north of Seoul right before it was even named. And this one is Polygonatum infundiflorum. And the cool thing about this is when it flowers it smells like lemons and I mean really strong lemons. It is an incredible plant, so we gave it the cultivar name of 'Lemon Seoul'. So polygonatums are all deciduous. So, in the wintertime they disappear. And they grow from rhizomes below the ground. So, if we were to... let's see if I can pull one up. I'm not sure, but we give it a shot. Boy they're really in there good aren't they. We didn't get them. Okay, there's a rhizome attached to the base of that so you cannot grow it from this because there is no growing tissue in here.

Q: Would you like me to hold that?

A: No, it’s compost now.

So maybe I'll find one we can pull up. Polygonatums have very knotty rhizomes, and some can have rhizomes as thick as your wrists. So, if you want to multiply a polygonatum, you can go in with a shovel and as long as you have a stem, because each stem is attached to a growing point, they transplant very easily. You can transplant them 12 months out of the year. Now if you... some, like this one, this started out from one rhizome, one stem so it multiplies and makes a big patch. Some, the rhizomes never branch. You start with one, you'll always have one. So, what you have to do then, is dig up the rhizome and cut it in one-inch pieces. Take a knife, slice it one-inch pieces. You will not see anything for generally two years above ground. Because what it has to do the first year, it has to take all those, it has a bunch of blind eyes, it's like a potato. And then those eyes have to develop and then the following year, you'll get a shoot. So, when you divide it if you again have something with no stems on it, don't be afraid you've lost it. You've just got to be patient because - two years before you'll see anything above ground and then it'll come back and start to spread. They also will form seed if they're pollinated. So, if you come back in September, all of these have fruit. And the fruit is very easy to germinate. It's very slow. Two years and you'll have a little plant about that big. It's painfully slow so you're talking generally five to six years to have anything that'll flower. So not fast, but it does work. You need to sow them fresh. If you sow the seed after they've dried out, no good.

Okay, now here is the European version. There's a European this has one called Polygonatum multiflorum. They have two, multiflorum and odoratum. Well, they're very, very promiscuous. So, this is actually the hybrid called hybridum. You know a lot of things are allowed in the EU that aren't allowed in the US. So, this is a gift, started from one plant and was in full bloom for the last several weeks. Really quite extraordinary and this is a Polygonatum hybridum.

Okay, this is a another one of our Korean collections. This is Polygonatum lasianthum. That's as tall as it gets so it's a foot tall absolute max. So, as I say you can really get one to fit almost any situation. And for most people looking at them, they're going to look fairly similar except for size. You know to those of us who study these, it's a little crazier and I will add if you really like polygonatums, there is going to be the first ever Solomon's seal summit this year. It's held in a little island off the coast of Seattle where Solomon's seal experts from all over the world will be convening to spend three days talking about nothing but Solomon's seals. So, there's... for every plant group, there's enough plant nerds for these fun little convergences.

Q: Do all of the polygonatums have that pretty fall color that the variegated...

A:  Most of them do, yeah, the bright yellow yep mm-hmm. Yeah, they're really nice and fall color. Some climates they're better than others. If we have a cool fall the colors going to be much better than if we have a warm fall.

So, we just, they're just so many in here and I'll just show you a few. We'll go on this is another one this is a latifolium. One of my favorites. It's very dense and just a really good dark green.

Q: Will these take morning sun?

A:  Pretty much all Solomon's seals will take at least half day sun. In the wild, where you find them, they're in deep shade. They grow much better if you give them more sun. They will clump up better they're just a far superior plant. We've found anything, like I say, up to about half day sun is fine.

So, we've looked at polygonatum. Now here is False Solomon's seal. This is the genus Smilacina. This is also a native to the US and to Asia. This is our US native and instead of having the flowers hanging down, it has the flowers at the end. And so, the same thing, the fruit will be at the end. On our native the fruit is more of a sort of a reddish bronze as opposed to most of the other Solomon's seal which is a black to blue. Okay, and actually while we're here we can look at a uvularia. This is our native Uvularia grandiflora. And this, you could find in the woods around here if you go out. It doesn't look quite this nice out in the woods. Instead of white flowers this has yellow flowers and they finished now but you can actually see a seed pod. Let me see if I can get that, figure out which stalk that's on. Yeah, there you go. And you say to see the seed. So, the interesting thing about this particular one, and a couple of our natives, the flower and stem comes right out of the middle of the leaf. Which is sort of weird. So, I really like these, and these are mostly fairly short. Any of these, probably a foot tall is going to be max in size.

Q: Are any of these things you mentioned, Tony, in this book?

A: I, honestly, I wrote this back in October and I don't remember but they should be. You can certainly go online, there's more, and we do have a good selection. We're constantly, because we grow so many, we're constantly rotating them in and out. But yes, a lot of those you will find. We just think they're great for the woodland garden.

So, we looked earlier at the lemon scented one, this is a bigger clump of that, and you see we've got it here where it gets a lot of morning sun. Where in the wild, where we found it, just dense, dense, shade. So, they grow well in both. Now I'll show you one other one while we're here. This is Polygonatum falcatum. This is another one, beautiful little plant, just finishing up and that's also from the same trip growing nearby that in Korea.

Okay, now we're passing by another of the False Solomon's seals. The genus Smilacina. They're really attractive plants.

Okay, we've looked at mostly Asian European. This is our US native Solomon's seal. This is Polygonatum biflorum. And biflorum gets about this tall, it could be a little shorter, a little taller. And then there is a different form of that that is got double the chromosomes that can reach up to 4 to 5 feet called commutatum. But very, very similar. Botanists are still arguing whether they're two different or just one has more chromosomes than the other.

This is also a polygonatum. And this is what we call the whorled species. They have their leaves in a whorl and they also develop in the woods but they like their head in Sun. So, they develop these leaves that actually have tendrils. And so, they can actually hook on to whatever tree they're near and climb so that their feet are in the shade, but their head is in the sun. And these are absolutely fascinating. There's a whole number of this group of these cirrhosis or cold world solid missiles we particularly love these just and the colors are like nothing else they come in pink they come in reds, oranges, yellows and also white they're called whorled, W-H-O-R-L-E-D for the arrangement of the leaf. this particular one is Polygonatum kingianum. It's a pretty, it's a pretty crazy looking plant. We offer it occasionally. We don't have this one right now, probably we've got to build up about another year. So, this one doesn't multiply real fast so when we offered it might be another five years before we offer it again. So many of these plants, you can't just pick up the phone and call the wholesaler and buy. You have to... and that's why you don't find them at the box stores. But they're very cool.

Now behind us, it's one of the evergreen Solomon's seals. This is the genus Disporopsis. This is kin to our native disporum, except it got some extra letters so it got to keep its leaves. So, this one, beautiful in flower, just getting ready to start opening. Completely evergreen. So come out in January, it's the only group of Solomon's seals that does not lose their foliage. So really an amazing group and also one of the most shade tolerant. This can go in the darkest conditions imaginable. It's really an extraordinary plant. We've got about six different species of the disporopsis.

Q: Does it look good all winter?

A: It does. Probably by, generally by late February early March it starts getting a little tattered. We go in, around the first of April, cut it to the ground so that the new foliage will reflush.

Q: This one too?

A: Yes, Okay. That is the disporum. So that's this, without so many letters. So disporum is called fairy bells and that's both US native and Asian. The Asian ones come in a lot of different ones. And in the disporum group there are clumpers and runners. And this is obviously a runner that started from one. So, it never develops a big clump. It's just one piece here, one piece here, one piece here, so it pops up.

We'll look at another one right up here. This is one of the most unique of the Solomon's seals, the polygonatums. This one, the leaves come out green and then they develop a white center. And this was actually developed for the cut flower industry in Japan. And if you come back in a couple of more weeks, these leaves will be probably 60% white and it remains that brightly colored throughout the year. And this is a cultivar called 'Byakko' which means something like snow tiger. The most common Solomon's seal in the trade is actually the Asian, European Polygonatum odoratum. And there are many, many forms of this from Japan there's probably now up to 20 different cultivars. Most of them, the common one is just 'Variegatum'. It has a creamy edge around it, but just a fantastic plant in the woodland garden.

This particular one is 'Fireworks' because this has more of a streaking through the center of the leaf as well, contrasting with the red stems, is really quite stunning. Now this is the same species, and this is one from our Korea trip also. We found this really compact one and we named it 'Pacman'. So that is one division. So, this is about a 15-year-old clump and that's as tall as that one gets. So just in the, see in this deep shade, it really does fill in very nicely. So here more of the running disporums. So, here's one this is called Disporum sessile. Sessile runs like crazy. So, we've got this one, we've got the green one, and we got the white edge one, and they're all just sort of running together. So, if you want something that runs, it just pops up. If that fits your design scheme, that form sessile is your plant. So hopefully that'll give you a little bit idea about what Solomon's seals are, what they do, how you can use them in the garden. If you have any questions, I'm glad to entertain those. Yes?

Q: How far north do they do?

A:  How far north? Wow, there are dozens and dozens that will do fine in Minnesota. There's only a few, the disporopsis, because they're evergreen, they're probably not going to go north of zone... I've heard 7a or 6b but most of the others that are deciduous going to go way up north. But some of the best ones I've ever seen, they generally like colder winters so they really thrive in cold climates. Yes?

Q: Where does the name come from?

A: The name of Solomon's seals? I've heard several different stories I don't know if anybody ever knows the real story but I'm sure if you look online, you'll find every different iteration of how that was named.

Q: There was a couple that spoke at the arboretum, I think you were there...they talked about one from Vietnam that's like eight feet tall. Do you have that?

A: Yes, yes. We do. It doesn't grow quite that tall here but that one I showed you with the whorled leaves, that's what it is, it's one of those. And so, the reason it's so tall it's because it climbs. It just hooks onto a tree. We saw some what we were in China that were bordering on 12 feet tall. So, if they as long as it got good soil at the base and moisture and something to climb on, there really is no limit to how tall they can get, so we got some great yeah, we got some great pictures from there of just dried specimens that were just crazy tall. And the one they're talking about from Vietnam is right on the edge of marginal here so it's never going to get 8 feet here. But it's very closely allied to that but with a creamy flower. Yes, other questions? Yes?

Q: Do the evergreen ones take dry shade?

A:  Yes. Absolutely they do. Yeah, the disporopsis are probably one of the best plants ever for dry shade. Now they're not going to grow as vigorous as they do in moist shades, but yeah, they're top-notch. You'll see some clumps around here they're in really dry. Yes?

Q: What is this one?

A: Ah, this is another one. This is the shortest of all. This is Polygonatum humile. So humile means short. So that's what the rhizome looks like under the ground. So, and this one does spread. We've got some big clumps of this you'll see. Now, if you wanted to reproduce that, and you didn't want to wait for it to do it on its own, you break this piece off. And all those eyes will develop over the next year and then one to two years from now you'll start having a little shoots. But everywhere you break that, there you go. Polygonatum humile is just one of the absolute best Solomon's seals if you want something short because generally, you'll hear it's four inches, if you've got a little more sun two inches max.

Q: How often to you amend the beds?

A: Okay. Question was how often do we amend beds. Once, when we do it initially. Every bed on the property is 50% compost 50% native soil. Once you amend, unless you burn that compost up by doing something like putting chemical fertilizers on it, that compost is going to remain. Now we mulch each year and mulch, after a period of six to nine months, turns into compost. And then compost turns into humic acid which it basically replenishes in the soil. So, it's always important that you mulch to keep the microbes happy. To give them something to eat.

Q: Most Solomon's seals, you said the disporopsis does well in dry shade. What do most of them want as far as moisture?

A: Honestly, the majority of them are pretty good in dry shade. They're never going to grow as well in light shade. They're never going to grow as well as in a reasonably moist... they don't like, none of them like moist soils. But they all just sort of like average, what we call mesic soils just basically not too dry not too wet.

Q: So, if you have an area that is a little damp, these would not be good ones?

A: Not this stays damp, no. No, you're not going to be really thriving in that. They really like it dry. If you look down here this disporum, you'll see it doesn't go down to the water it actually comes up on dry ground. So that's a great key to look at how they do in the wild. So that one is coming up on the driest part. Under here it is bone-dry.

Q: So, is that true of the disporum type of polygonatum?

A: Yes, yes. They really prefer that just average to dry. Not average not moist. Yeah, no they don't like wet. They generally won't die but they're just not going to grow.

Q: You're right, mine hasn’t and I didn’t know why. It’s getting too much moisture.

A: Very possible, yeah. Any other questions?

Q: You have a very beautiful chinaberry tree.

A: We do. This is a very interesting story. Chinaberry, when I grew up in Raleigh, was a weed tree. You know, you'd have it on the school grounds where nothing else would grow and you'd shoot little girls with it you'd pop them. But back in '84 when we had a hard winter, they all died. This particular one, which has variegated, almost white foliage, was found by a friend of ours. He's a bulb guru, Scott Ogden down in Texas, and he found it and it comes true from seed. He sent seed to the late JC Ralston and JC named it and actually introduced it to the nursery trade. It's called under the name of 'Jade Snowflake'. So, you feel free to pick up seed all around, in front of there, on the brick and they come completely true. And the fragrance of the flowers is amazing. The little purple flowers, just delightfully fragrant. The only downside is you will notice, like potato chips, you can never have just one because it does produce so many seeds. Thank you all very much for joining with us this morning. Thank you.

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