This edition of Gardening Unplugged was recorded on Feb 25th, 2022 during our winter Open Nursery and Garden Days. There are few perennials that can rival the seasonal interest of hellebores ...often called Christmas Roses or Lenten Roses. These staples of the winter garden are among the most coveted of garden plants by those who know them, yet they are still relatively unknown outside of plant enthusiast circles. JLBG Director Tony Avent discusses the history and cultivation of these wonderful deer-resistant shade perennials.
Okay, I'd like to welcome everybody to our... some of our first classes of the year. Nice to have everybody back. And today we're going to talk about hellebores. For those that have grown them, if you haven't, we'll give a little bit of brief background.
Hellebores are almost entirely European natives. A center of distribution is the Balkans. Several years ago, we were lucky to go see these in the wild in the wonderful destinations for vacations of Bosnia, Croatia, Slovenia, Montenegro, and so forth and so on. In the wild, some hellebores grow in the woods but the majority of them actually grow in prairies. So many of them in sun, especially as you get into the areas of Bosnia where pretty much every tree has been bombed out. Things that didn't used to be in sun are now in sun. Now in the wild, this is what a hellebore would look like. That is that is a hellebore that we collected in the wild. So, to get to where we are today, that's required a lot of breeding. So really for the past 50 years that's where hellebores have been improved so much in terms of color, in terms of form. Every double you see originated from one that was found by a friend of ours over in in Croatia and we actually went and visited the site. It was just one population where half the plants were double flowered. So, everyone you see today all originated from that one find in the wild. So, it's amazing how they've gone from where they were to where they are today. So, let's move into a little more shade over here and we'll...
Q: What's the name hellebore mean?
Tony: That's a good question. I should remember but I do not. Apologies. (Editor's note: The name Hellebore is possibly derived from the Greek words 'ellos' and 'bora' meaning 'food for fawns' or 'elein' and 'bora' meaning 'poison food'. Sources differ.)
So, with hellebores there are... we divide them into several groups so to make them make sense the one outlier of the group is one called Helleborus niger. It's often called the Christmas rose because it's one of the earliest to bloom, typically blooming around Christmas. That always faces, always is white, and it always faces out. It's the only hellebore species, now take that back, one of two that naturally face out. All the rest of them face down. So, what you typically see is called Helleborus hybridus or what we see here. Hybridus means it's a mongrel mix. So, there's probably at least five species in all of those. Helleborus viridis is where the yellow comes from, Helleborus purpurascens is where a lot of the purples come from, H. orientalis is where the whites come from. And they just mixed all those up together and that's where we got Helleborus hybridus. When you grow hybridus seed, and obviously they're going to seed all over your garden, you're going to get everything back through many generations. So, if you buy a double purple, it's probably not going to seed double purple unless you isolate it. The more you isolate it... when I say isolate it, we're probably talking 20-25 feet apart. The bees are just... they're pollinated by honeybees. And honeybees, as you know, fly a pretty long distance. So, the better chance, if you want to keep a fairly consistent color, plant them 25 feet away, put a lot of that kind in there so the bees don't have to go far to pollinate them. A lot of people don't like them seeding. If not, as soon as they finish flowering, just go cut the flower stalks off. You will not have any seed. But niger is very different again because it's flowering early so typically niger doesn't cross with all these other species that made hybridus. And up until a few years ago we didn't think it was possible that they crossed. Now somebody has showed us that we're wrong so a lot of what you see now, without facing flowers, a lot of that came from mixing Helleborus niger.
Q: Yeah, I was wondering... you say cut them off, so they don't seed but the flowers just look so good so long. How do you know when you need to cut them? At a certain time of year?
Tony: Ah, okay, if you look where the flower is, look in the center of the flower. You will see what are called carpels and those are five little tubes. The minute they start turning yellow you've got two three days.
Q: Oh wow, okay.
Tony: And then, if not, it dumps its seed. So, very important that you know when to do [that].
So, the colors you can see these are all some that we grew from seed from strains, and you can just see the color. So here we've isolated these together and we will come in and take seed off these because we know these will be fairly consistent. And again, what we're aiming for now are things that face out. So, you can see right here, this one completely faces out. So, 10 years ago you would be very hard pressed to find one that faced out. Now, every year we will come in and we will take out older plants that don't face out and replace them with newer ones that do. And eventually, we'll get to the point where all of ours will face outwards. So, in the wild, they're protecting their flower parts for the insects and against rain and freezing. Because over in the Balkans, it's pretty easy to have a snowstorm when the hellebores are in full bloom. And if you've got all your sex parts up here, you know, big snow comes in, flowers broken off. Some of the areas we visited, everything had been smashed because of a recent snowstorm. Now, a couple of things that happened very interesting recently.
People went in and they realized they could cross with niger and some of the other species. Again, that was thought not to be possible. And they created things like this. This is Helleborus nigercors. So, this is a cross between one called Helleborus argutifolius that used to be called Helleborus corsica hence the name nigercors. So, it was a niger corsicus. These all flower in white, nigercors, because there wasn't any color added to those. Most recently we have these, and this is niger crossed with a number of species, lividus, argutifolius, and they've created what's called the ice and roses series. Now once you cross with niger, your offspring are all sterile. So, you have no more seed to worry about. So, you've got two main strains now. You've got the iburgensis strain, which is all... most of these are coming out of Germany, one group out of England, and the gladorfensis strain. This is a gladorfensis that has absolutely no offspring ever. Completely 100 percent sterile. This has been in bloom since... oh I'd say probably now 4 to 6 weeks. So, the bloom time, because it doesn't set seed, is just longer. These are actually blooming machines. So, back here on this row this is the other series. These are the iburgensis and, if we hadn't just cut the foliage off, these have beautiful, patterned foliage. All the patterned foliage comes from one species from Spain called Helleborus lividus. It is one of the most beautiful species and it is the one species that requires sun. If you put lividus in shade, it is not going to be happy. And we can show you some on the back patio, beautifully patterned leaves with just veins that are incredible. Flowers are sort of a greenish color, but flowers face out. So, we like that.
Q: Yeah, are you working on any new varieties of the gladorfensis?
Tony: Those are all done in Germany. They have the parents to make that cross. Because these are sterile, we can't make any crosses with them, so....
Q: You don't have their parents, or you can't get their parents?
Tony: Oh no, they keep those under lock and key. Those are worth hundreds of thousands of dollars to them and generally finding those parents is something that happens accidentally. You make one cross that's supposed to be sterile and if you make... grow a thousand seedlings you have one plant that will set seed and that's what they use to create all of these. So, they've got the keys to the kingdom that we don't have.
The colors you can see range. This is, as I mentioned earlier, from Helleborus viridis. You're getting these beautiful yellows and pretty much all the hellebore started with a couple of people. Really Helen Ballard of Germany was really the queen of the hellebores. She started the hellebores breeding. That's where it really got its roots to make these crazy flowers and it moved to England. You had people like Elizabeth Strangman who's actually still alive, incredible breeder, and then from there it began really being branched out. In the United States, the people who really made the huge inroads were the O'Byrnes out in Oregon and they still breed. So, a lot of the strains that we sell where you see the names, those are seed strains and we sell them unflowered. The only way we can do that is we know that they are so conscious about hand crossing the best of the best and their percentages come 98 to 99 percent true-to-color and true-to-type. That's if you just do it out in the open, as we mentioned, you might get 30 percent true-to-color, even isolated.
So, there's a lot of really... there's a lot of new people getting into hellebore breeding. Pine Knot certainly, up in Virginia has done a tremendous amount. They got a lot of their material from England. Probably in England now if you go over there the best place to go is Ashwood. It's run by our friend John Massey. John and his staff have done the most amazing... if you want to today the best Hellebores hybridus in the world are from Ashwood. And that's in sort of central England, it's worth a visit. Two years ago, we were there right before pandemic for hellebore season and the colors, the intensity the colors, is unlike anything I've ever seen so we were very fortunate to be able to bring back quite a few and we'll start getting seed from those and hopefully be able to offer more of those in the future.
Q: You mentioned the O'Byrnes earlier in Washington state?
Q: You said that they isolated them. How do they do that? Do they keep them in a greenhouse?
Tony: They do, yeah, they keep them in a greenhouse. They're actually in Oregon but yes, everything they breed is in pots, so they keep those in a greenhouse, no insects allowed, and every year they continue to upgrade. So that if you get something better, that's why. Their strains continue to improve every year. Yeah, it's not an easy thing; to make hand crosses of hellebores. And when you… if you look at the flowers, you will notice there's the little things around here are the pollen. You can actually touch them, it'll come off on your finger. Right in the middle, are the ovaries. And so, you take the pollen from there do, it on the ovaries, and then you've just pollinated your hellebore.
Q: So, if you want the way to get a double is to have a double parent and a double pollinator as well?
Tony: The only way to be sure you get doubles is to cross a double with a double. If you cross a double with a single, you get what is known as an anemone. Which means you got one set of petals and then you got sort of a collar. You remember those people in the paintings from England where they had those ruffly things around your neck? That's what you get with a hellebore if you cross a double with a single which is really fascinating. I mean, you'll see some today... there's some pretty amazing plants and we call them anemones and we have a few we never have a lot because they're... you don't get a high percentage of those. So, let's go look at some lividus and we'll look at a few other colors as we walk around.
Q: Are any bred [using] tissue culture?
Tony: Ah good question. Okay, you can see I'm just walking you through some different colors. The question was - Are they tissue cultured? Yes and no. Anything that is crossed with niger, tissue culture is fairly easy. Anything of Helleborus hybridus is almost impossible. There's really one lab in the world in Japan that has mastered hybridus. All the rest of them have failed miserably. So, you would think they would all be okay, but they're not. Now I mentioned earlier most of species are from the Balkans, there is one species in China, and it was one of the last species to be discovered. And that's pretty unusual to find and it's a very early one and it lives in bogs. It does not like to live dry so the complete opposite of all the others. It's an odd animal.
Q: What's the species of that one?
Tony: From the China that is um....
Tony: Sorry, no, my brain just shut down. I'll tell you this, I'll tell you in a second. I talked [about] a lot of plants today so ...
But you can just see the array of colors. And just to give you an idea of how far they've gone, take a look at some of these. This is 'Painted Doubles' from the O'Byrnes I mentioned. I mean to think that they went from that little plant to something like this. I don't think people that are not plant breeders can conceive of the years and years and years it takes to go from that little dinky plant to something that really nice. But again, pass that one around and you can see how even the seed strains vary. So, all three of these are from the same seed strain. These are all painted doubles. So, you see that's got the biggest flowers but they're hanging down. That one a little smaller but they're facing out and then this one late. So that's what you would get when you buy a seed strain. They're very similar but each one's going to be a little bit different.
So, here's some more of the gladorfensis. These are called the ice and roses strains so just a very dark foliage, all out facing flowers, and completely sterile.
So over here in the sun is where we keep our lividus. So, this is Hellebore lividus. This is where all the intricate patterns of leaves come from. This species from Spain. It requires sun, do not put this plant in the shade. It will sulk or die. And small flowers, I mean the flowers are not fabulous but there's a lot of them. When this thing fully opens in another week it's an amazing show. All the books say this is not winter hardy. And many years ago we invited to speak, one of the foremost expert [of] hellebores in the world, Will McLuhan, and he's doing a talk here in Raleigh and he's mentioning something about this plant and he said - It is absolutely not winter hardy at all it's very, very... you can't take frost and anybody who sells this and tells you it's hardy, they got the wrong plant. And so, I said - Excuse me, I said - we have this growing and it's absolutely fine for us. He said – Well, it's probably the wrong plant. Where did you get yours? I said we got it from a seed dealer called Will Mcluhan and he just – damn, damn and what he... what had happened one - in England, they get no summer heat. This is a species that requires heat and because of that, it never developed any winter hardiness. Because we're hot, it's absolutely rock hardy for us. We've had them out for decades with no problems. So, it really does matter where the plant comes from and where the plant's being grown. But this also has out-facing flowers so when you cross this with a niger, all your flowers can't help but being out facing.
All right, do we have any questions? I've talked a lot about... I hadn't talked a little bit about cutting back, so that's something very important. Hellebores are evergreen so they have foliage that remains year-round. You do not have to cut the foliage back. But by the end of February, the foliage is going to get looking a little ratty. So, what we do, the minute we see color on the new blooms, we cut all the old leaves back. And we do that simply for appearance. It doesn't affect the plant one way or the other it just makes it look nicer. You'll notice all through the garden we've gone through and cut all the old foliage back and you can do it now. Don't do it in the middle of summer. Hellebores go dormant in the summer. That's their summer months from really late May till October, they are dormant; they're not growing. Do not divide them in the summertime, you will kill them. The only time, if you need to divide a hellebore, once it gets cool; October, November, December, January, February, you can divide away. After then, wait till next year because you will kill it if you divide it the wrong time of year.
Q: You mentioned this one has the hybrids that all have beautiful foliage I think like ‘Anna's Red’ and ‘Penny's Pink’ are some examples.
Tony: That's the parent that's what gave it all that beautiful color that plant.
Q: If this one needs sun does that mean that it's children probably need a little bit more sun? Because some of mine are ... and I wonder if that's why.
Tony: They actually do better in some sun. Not full sun, but a couple hours of sun or a higher canopy of shade. Anything that has that as a parent absolutely does.
Q: And then i had another question about... you said cutting back?
Q: I was looking on the internet about black death and I guess it's something that can impact hellebores? Do you need to clean your clippers between every plant you go to prevent it?
Tony: If you've got black death in your garden. Black death is a is a weird pathogen that just comes in and looks like somebody took a black magic marker and just marked up your hellebore. It's almost unknown in the U.S. Not completely unknown, we had couple plants... a couple, I'd say probably three or four years ago they had it. Dig it up, bag it up, throw it in the dumpster. Haven't seen any since.
Q: And would you replant the same thing?
Tony: We did yeah. Yeah, we put it... you can take, I would do a, if you actually have that, do a Clorox drench. Just get like a 10 percent Clorox solution in a watering pot, drench it, you're good. But the chances of most people in America ever seeing black death is so minimal. It's a much bigger problem over the EU.
Q: You said about waiting for the color to show...
Q: Does it hurt it if you don't wait?
Tony: Great question. Do you have to wait till the color? The reason you want to wait is because those leaves keep the ground cool. They keep the hellebore from flowering too early and if it flowers too early and you get a night down below 15... 10 to 15, you're actually going to lose the flowers. 15 degrees probably be okay, it'll damage the flowers, but they'll be back. But if you cut too early and you get some sunny days, they warm that ground, and it pops too early. So that's the only reason to wait. So, once the flowers are showing color and they're generally up above the foliage it doesn't matter because you're not going to slow anything down at that point. So, it's more... it's more of you're taking a gamble that you won't have a cold drop that late. If you do now... so if we if you come out here in the morning for open house and it's in the 20s, all the hellebore stems will be like this. Not to worry, as soon as it warms up, they pop right back up. Now there's only so many times they can do that. If you got 30 nights like that, we're down up down up down up they'll eventually wear out. But they'll take a dozen or two with no problem. So that's just the nature they are wired to deal with cold weather. Great questions. Any others? Yes.
Q: In the fall of, I think 2020, I got a huge flush of foliage, which I haven't seen any other year, and I’ve had them for 15 years.
Tony: Yes, yeah. More than likely what happened that year, you had a little bit of cool weather, and it shot them into... they got their winter chill requirement. And then you get warm and they're like its spring and they start growing. Not ideal, but they're fine it won't really hurt the plants. But yeah, we see that occasionally when you have these falls where it's cold and then warm again.
Great questions. Any other? Yes.
Q: I put a newly purchased hellebores in a cold frame for a couple months and looks like it started to get powdery mildew.
Tony: Yes, yes, most likely botrytis, which is sort of like a gray powdery mildew. You need to keep that treated because if you have a hellebore in a cold frame and it's moist outside, it'll kill the whole plant in a matter of three days. Yeah, that's a real problem and that's why when we grow them in our greenhouse cold frames, we have to have fans blowing on them constantly. If you didn't have those fans on, we could lose a greenhouse literally over the weekend. It's that fast in a container. In the ground, you're not going to see a problem but in containers, in a production, in a cold frame, huge problem with botrytis. So, you would need to invest in in looking what could be treated for botrytis. You may be able to do it with some oil sprays, I'd do some research online to see.
Q: Can you permanently get rid of it?
Tony: No, botrytis is in the air.
Tony: No. So, it comes in, it's an airborne pathogen, so no matter as long as you've got the plant that air blows in, you're going to get it. You can't get rid of all the botrytis spores. So, it's not in the plant, it's on the plant. So, it's not like systemic in the plant. Once you get rid of it, the plant's fine. Yeah, so some pathogens actually go into the plant, not the case on that.
Yeah, that's a great question. Any other questions?
Q: Do you keep all your seedlings for sale, or do you cull some of them?
Tony: Ahh, what we do is we are very particular to what we gather so it's got to be isolated enough. It's got to be enough nice ones together. So, we have a big spreadsheet and then we will grow them and say we grow between 100 and 500 of a particular one. When they flower, which takes us two years minimum, we hold everything until they flower, we would throw out probably 50 percent. So, a lot.
Q: Flowers are no good, or the foliage?
Tony: The flower is not up to our standards. 'No good' is one of those relative terms. Most people that don't have the....
Q: Hybridizer eye?
Tony: The hybridizer eye, that's a good word to say. We keep all the stuff that we throw out, but we are incredibly particular. So, all of those you see flowering up there are some that I personally, I’m the one that picks everyone out, and my standards are pretty high. So, it's got to be rather exceptional to get into our winter delight strain. Yeah, I mean you throw a lot out. It's... you'd be shocked at the numbers.
Q: What is the species of that one again?
Tony: This is a hybridus called 'Painted Doubles'.
Q: Perfect name.
Tony: Yeah, isn't that... I mean, it really is an absolutely amazing plant.
Q: Is it for sale now?
Tony: It should be - if we're not out.
Any other questions? Thank you all very much for coming and enjoy walking around!