Gardening Unplugged - Hostas in the Garden

Gardening Unplugged - Hostas in the Garden

with Tony Avent

By Published August 2022

Join Tony Avent as he gives our guests a primer in hosta history, breeding, and propagation. This video is part of our Gardening Unplugged series where guests at our Open Nursery and Garden Days have the opportunity to learn about the wonderful perennials at Plant Delights Nursery and Juniper Level Botanic Garden. Gardening Unplugged is always free and supports the educational outreach mission of Juniper Level Botanic Garden. Join us at our next Open Nursery and Garden Days.

Hostas that Tony mentions in this video:

 

Video Transcription

Hostas look the way they do depending on the species that they came from. The most popular species today, and has been through history, is this... this is Hosta sieboldiana. Hosta sieboldiana is the only hosta that is blue and corrugated. Now, supposedly sieboldiana has never been found in the wild. Some people theorize it's a really old hybrid but it's very steady, so anytime anything looks like this with corrugation in blue, it's got sieboldiana in its background. So that's always going to be number one. It's hard to really get away from that. It's not a hosta that grows well in the south. It's one that really prefers cooler climates. We've actually spent years breeding so this is one of our creations. We basically went back and recreated several hundred-year-old hosta, which is called elegance, to create one that will grow in the south and have good vigor. So that's the type [of] things we work on. Hostas are genetically very unstable, sort of like the people that collect them. They mutate a lot. So anytime you get a hosta you're liable to get, it'll mutate to a variegated edge, it'll mutate to a streak, it'll mutate to a center, it'll mutate to gold. And that's where we really got the first golds, were through mutations. You can see right up by the house, is one of the gold hostas. And you can see, because the leaves are very corrugated and they're big, that has sieboldiana in the background, but it's got other heat tolerant ones that gave it the vigor.

New Realms of Hosta Breeding

So that's what we love about the hosta, the current hosta crop of breeding, is we look for things that add vigor to a hosta that we may not have been able to grow. To the right of that is a cat. This is Kit-Cat, yes Kit-Cat loves to star. This is sort of the new realm of hosta breeding, so we went from this, which is, again, got the sieboldiana backgrounds, to this. So, this brings in a lot of the Japanese rock hostas. In Japan, now hostas, let me back up. Hostas are primarily prairie plants. The majority of hostas do not grow in the shade. That is a myth. In the wild, they grow in prairies. They grow with day lilies. And so, grasses come up and they bloom, and so during summer, you live in very misty environments with sort of grass plumes over top [of] you and that's how they survive. But it's very few hostas that you actually find in the shade. There’s a couple. But in Japan, you have a lot of the rock hostas. They occur actually in the cracks of rocks where they hang out over the cliffs, and they have long arching leaves. And so, by breeding those in we're able to get new plants like this. These are sort of the new generation of plants. It's been very tough getting people to accept those because they want the big blue. Everybody wants the same type of look, but these are finally starting to catch on. Hostas vary in size. There are some species, the smallest one is one called venusta, and it, in the wild is only this tall. it occurs one place in the world that is one island off the south coast of Korea, so we were fortunate to go visit that back in 1997. The entire island is grazed by goats. So, every hosta is now this tall, even though it used to be this tall. They're not reproducing anymore because the goats have just devastated them. But if you want to shrink a hosta down, that's what you do. So, something like here in the front, we know size wise and shape wise, that that was bred with Hosta venusta. Hosta venusta is a species we know because it's got really rigid scapes. You can feel at the base of it. So, all the hostas have been created now based on the traits you particularly want to impart from those original species. So, let's take a look at a few more.

Kit-Cat, always the star of the show
Kit-Cat is always the star of the show

So, if you look at this one over here with the really long leaves and really ripples. This is another Japanese species called Hosta montana. And that's one that was brought in many years ago but all the early montanas that were brought in came from the bottom of the mountains. Hosta montana grows from the bottom of mountain to the top of the mountain. The ones at the bottom, they will come up in February and the frost just wipes them out. Just every year this was the first one up, first one to get frosted. So, the guys went back, back in the 80's, and climbed to the top of the mountain and brought them down from the top of Mount Fuji and then those emerged much later. So that's where the really cool breeding has come from so anything you see with those long arching leaves came from Hosta montana. So that has been a really good one. If you know a plant called 'Sum and Substance', one of the most popular hostas today, that had hosta montana blood in it. It also has remotely some hosta sieboldiana in it. If you look at it when it gets old, it does have a little corrugation and the leaves are round, but this is what gave it the heat tolerance. So that's why that is one of the most vigorous hostas today because you took the two largest species known to man and you crossed them together and you created this absolutely giant monster. So here you can see this is uh one of the newer cultivars, but you can see that corrugation in the leaves. So, we know that came from Hosta sieboldiana. We know that goes back to that original blue, but you can see the leaves are more pointed and that tells us it's got some of the other species in [it] which is how we get vigor imparted to the new hostas. And again, you can just see the different ways in which now hostas have evolved from where they used to be. So, we'll take a look at some hostas in the wild and what they look like if you brought them in from the wild. The key for us is evaluating for vigor. Now take a look at this little dwarf one here. Here's what we're looking to do with the blue, is try to say all right, how can we take the big sieboldiana and shrink it down to make something that has round corrugated blue leaves but is dwarf and has vigor. So, we... those plants I was telling you about, the venusta from the island in Korea, we brought that back and then we made that have sex with itself over and over again. And each time we would select the smallest one that had good vigor and when we finally got to the point then we crossed that with this and were able to create a series of really vigorous dwarfs. Because up till then, most of the dwarf hostas were not vigorous. They were dwarfed because they wouldn't grow and so our idea is to create dwarf hostas that really have excellent vigor.

So you see, here's another example one of those crosses that's probably got Hosta sieboldiana but also Hosta montana. Because it's got the big leaves, it's got some corrugation, but look at the vigor. So, we don't get that except out of the Hosta montana and keep the size. And you can see very similar ones. This is also out of the Hosta sieboldiana but is crossed. In this case, this entire line started in England. The late eric smith, he was a famous plant breeder. So, he had, in the fall, a hosta called 'Tardiflora'. It's a species, a selection of Hosta longipes, which is another one of those Japanese rock hostas. It blooms in September. That's its natural time to bloom. So, he had, it was blooming, he had a Hosta sieboldiana that they had cut back for some reason and in the fall, it threw another flower scape. And he crossed those two. Nobody ever done this because you're crossing a hosta that normally blooms in April may to one that normally blooms in September. And he created a whole series called the Tardianas. And that was the first ever midsize blue hostas with vigor. So, a lot of those still on the market today. The most popular one is halcyon, which many of you may have heard of. This is still today, one of the most popular hostas. And then there are many, many sports from that so we talked about how hosta sport. Things like 'First Frost', 'Autumn Frost', all of those came from that original cross that then mutated.

Here is a great example of one that came from a mutation. This is a, this is Hosta 'Mini Skirt'. This started out with a cross with the little Hosta venusta a cross on sieboldiana, so it made this small blue plant. Then it mutated and it mutated in what we call ploidy levels. So, it had a chromosome shift. That chromosome shift made it genetically very unstable. It was called Blue Mouse Ears. And Blue Mouse Ears sported into literally several dozen sports, and this is one called Mini Skirt. So that genetics, it started out with one original cross and then that has had now about five different mutations to get to this point. So, these are really amazing. Some hostas, as we mentioned, have edges. Some have center patterns. The more pattern it has on the leaf, especially in the center, the slower it grows because everywhere it has white it has no chlorophyll. Anything that has white in the center of the leaf must have more sun. Because if you put one with hosta in the middle of the leaf in shade, it has no ability to manufacture food and it will just shrink back to nothing. So, you've got to have it. Morning sun is ideal when the weather is cool. On every hosta, the more sun you can give it as long as you can put moisture to the foliage, the better off it is up to a point. They don't like afternoon sun. They love morning sun, and they love moisture. You can actually grow hostas as a marginal aquatic, and they are fantastic. They do not like dry shade so any book that tells you they like dry shade, that is absolutely not true. So, more sun the better... light shade. What we do here is we raise the canopy. So, we come in, we take the lower limbs out and that way we reduce the number of limbs that the light has to go through. So, hostas prefer what we call part sun to light shade. They prefer that you see dappled light on the ground.

Propagating Hostas

Now if you want to propagate hostas, they can be divided almost any month out of the year. And you simply dig them up and they easily pull apart. They'll almost fall apart. We've typically found about every 10 years you're going to need to divide the hostas. They will actually start to go backwards if you don't divide them. You will all of a sudden notice that the center becomes woody and then all the crowns grow up around it but there's nothing left in the center. Now the other interesting thing about hostas, you can actually go in, and I don't know if we can do this here. Let's see here. Divide them from a very small piece. Let's see if I can pull one up. At the base of every hosta leaf there is a dormant bud. If I pull that leaf off right at the base; you see that little nub? That is a new plant and it's just waiting to grow, and it will not grow until that hosta flowers. So, with the base of every leaf, so what we can do is you can go in you can use a knife or a clipper and take this plant and, you see where the base is, and you simply cut it. And then you re-pot that and now you will have two or three plants. It will cause one to pop from every single bud. I just pulled it up but normally you dig it up so it actually had a little more roots, but this will actually live. Instead of having one plant you will now have two to three plants. So, hostas, you can take literally this plant up, take each division, you could easily go by the end of the season have 50 divisions out of that one plant. They're really incredibly easy to propagate. There is no down time. Some people like to do them in spring, some fall, some summer, some winter, it really does not matter. It's all pretty much the same. Hostas will flower as I mentioned some in April may some not till September. So, let's look at just a couple more.

The Places that Hostas Have Gone

Now where hostas have gone... some really interesting places. This is a hosta. That's different. So this has one called Hosta gracillima as its parents. Gracillima is a Japanese species. It has the narrowest leaf of any hosta. If you want, so you can really create almost any look simply by going into the parentage and changing the parents that you use. So yeah, that's quite different. Here is a hosta we collected in the wild in Korea. So, this is what a hosta would look like, it doesn't look quite this nice, but that is what they look like in the wild. Unless you have a mutation, you will never find a variegated yellow, blue hosta in the wild. They all are green and this particular one, it does actually spread. Some hostas are somewhat stoloniferous. Now there is one hosta that's sort of the oddball in all the bunch and that is Hosta plantaginea. Plantaginea is from China. It is the only fragrant flowered hosta. And what's interesting, hosta flowers open up typically seven to eight in the morning. Plantaginea opens up at four in the afternoon because it is pollinated by nocturnal moths, and it is extremely fragrant. So, every hosta that you see for sale that is fragrant came from that original species. And that is the most heat tolerant hosta. It's the only hosta that does not require winter chill to come back up so it's also a very early one to come up in spring. It's a bear to breed with because again, regular ones open at 7 or 8 in the morning, that one at four in the evening. But if you can get that done, you got some pretty amazing things. So, there are a lot of fragrant hostas on the market today and anything that's fragrant is going to be sun tolerant and heat tolerant.

And then the last one I'll talk about is this. This is also an odd bird. This is Hosta ventricosa. This is the second species native to China, like plantaginea. This one is known for its very dark purple flowers that look like large bells. This one comes completely true from seed. Most hostas, if you grow hostas near each other, they're not going to look anything like the parent if you grow it from seed. This one will be 100 percent like the parent because this is what we call apomictic. It's been it's been messed with so long by nature that it just can't have sex with anybody except itself. So, this one will actually naturalize in the garden. It will seed around and do really nice. But you can see just the diversity from looking around as to what is, what has happened with hostas. The one over here on the right, it's probably the newest of the hostas we didn't have. Which, we didn't have anything that was large and blue with ripples in it. There was nothing like that because ripples are hard to breed with blue. So, we have this this is...my mind just went blank sorry about that...oh, Diamond Lake. And Diamond Lake is really the newest of the, of sort of the hot new hosta. Really quite incredible. Now one species that I haven't mentioned is Hosta nigrescens. So, let's take a look actually one more right here around the corner. Now nigrescens is really interesting because it's more of an upright hosta. And nigrescens was the parent of one of the most popular hostas of all times and that one is called Hosta ‘Krossa Regal’. So, this is one of the oldest cultivars of hosta but yet one of the most incredible. This has got nigrescens in it and it also [a] nigrescens variety, Elatior and it has very tall spikes. The spikes on this are seven eight foot tall but that's pretty good for a hosta that's been around now in trade for over 60 years. And that came... so anything a lot of breeders that want their things to have upright and actually be able to see the stalks, you breed with Hosta nigrescens.

So that's a good primer. Any questions?

Q: Dozens, the problem is my memory doesn't serve me well, but I have a lot of questions.

A: Okay, all right.

Q: Oh, they all left.

A: Well, if you find them again, let me know.

Q:  I've had variegated hostas that started reverting back to solid. Is there any way to prevent that or...?

A: Great question. As I mentioned, they're genetically unstable. So, it does happen. It usually, once it goes to variegation, most good variegates that are edge or centered should not revert. So, if they do, dig the clump up, take the variegated ones off, and throw the others away, and replant them and they should be fine.

Q: Can you talk about Hosta 'Time Traveler'?

A: Time traveler is a very interesting plant that has... All hostas have multiple layers. Hostas all have three layers in the leaves. They call them layer one, layer two, and layer three, or for short - L1, L2, and L3. So, what we found in hostas, is that one layer can have one set of chromosomes, another layer can have another set, and another third layer can have a third set. We used to think all hostas would have the same chromosome number consistently, but they don't. So, what happened in time traveler and stitch in time and others like that, the third layer is a completely different set of chromosomes. You have a different pattern and a different leaf thickness. So, Tattoo was really one of the first that, which was one of our introductions, to have that multiple layers that each one was different. Then when they started looking and analyzing it, they would realize that most hostas have a diploid set of chromosomes equals whatever eleven. And then all of a sudden, they found that the outside layer had two sets, the inside layer had four sets, and the outside layer had two sets. And some it was two - four - four, four - two -two... And so, once we found that out, there was all kinds of mutations that really started to show up. And it's really amazing. One of the most interesting, we actually walk back here, you see a couple of very interesting things.

You can see again, white center, more light. So, give that good light, that's going to grow. But really, over here is probably one of the most interesting hostas to ever come out. This is a hosta called 'Wheee!'. Now this is a mutation that changed the layers. So, the layers are different and because of that it created this leaf that was seer suckered and had these incredible ruffles. So, there's really no hosta that looks like that that has that amount of ruffling. But that's the same thing the layers are just different chromosome numbers.

Q: Does the variety and surroundings have much difference. Like coastal to mountains of North Carolina or North Carolina to New England. Is that variety... does it make any difference?

A: Great question. Yes. A lot of the hostas from the mountains prefer colder climates. As a typical rule, those hostas, if you go to a garden in Minnesota, they have the biggest hostas. And you move down here in the South, we don't have the same winter chill. So, if you have varieties that have mountainous species in them. They're not going to grow as well at the coast. So that's sort of what we've done is we're breeding for sort of hot. Yeah here, and south. So, any hosta that's fragrant is going to do great at the coast. Fantastic. So, you've got to look at things... that anything that has vigor here, is going to be great down at the coast. But if you get into Florida where you have no winter chill. So, get into say, central Florida, the only thing grow down there are the fragrant hostas. Because again, the only hosta species that has no winter chill is that plantaginea, that fragrant one.

Q: So that deals with size too?

A: Typically, the largest two are the first two I mentioned of sieboldiana and in montana. And those are primarily mountain species. Except for, I mentioned, there was a lowland montana. So, if you could still find that. That would be great in Florida because that thing tries to come up in February. So yeah, it's really about knowing what the parentage is for those species as to where you garden. But that's why I always tell people, visit a botanic garden near where you are, and you'll know which ones are going to grow. And the good catalogs will tell you. The bad catalogs will have every hosta stamped Zone 3 to 9. Every hosta is not Zone 3 to 9, it doesn’t work that way.

Q: Well, how do you tell a good catalogue to a non-good.

A:  That's a great question. Well, number one, look. If all their hosta says Zone 3 to 9, it's not a catalog you can trust. Look, you read online reviews. Trial and error. Honestly, a lot of it is trial and error. I mean we realized that the majority of catalogs, especially the larger ones, don't really grow their own plants. They contract with a grower who grows whatever they have and sells. Whereas smaller mom and pop nurseries actually grow their own plants, and they know what really grows. So generally, your smaller mom-and-pop nurseries are going to be much more knowledgeable than the larger guys, as a good general rule.

Any other questions?

All right. Thank you all so much. Thank you. Thank you for making the making the class.

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