Things are Rosy for Mother's Day! - A Visit with Dr. John Dole about Cut Flowers

Spring has sprung in the world of horticulture, and as Mother's Day nears, we welcome Dr. John Dole, a Professor of Horticultural Science from North Carolina State University. His current research activities focus on cut flowers, including new cultivar evaluations, production, postharvest, and marketing analysis.  Dr. Dole opens our eyes to the science of cut flower production, the crucial post-harvest practices, and the flower's voyage from farm to tabletop. With his expertise, you'll harvest a bouquet of knowledge on how to keep those purchased petals perky for longer, and you'll catch a glimpse into the science that ensures these flowers keep their sparkle from field to vase. You're sure to leave this episode with a fresh perspective on the cut flowers that brighten your life, and perhaps even a green thumb's itch for the season ahead.

To read more about this topic, check out Dr. Dole’s paper, “South and Central America Cut Flower Production and Postharvest Survey” published in HortTechnology at  https://doi.org/10.21273/HORTTECH04484-19.

Additional papers of interest by Dr. Dole in the ASHS journals can be found by going to https://journals.ashs.org/search?f_0=author&pageSize=10&q_0=John+M.+Dole&sort=datedescending.

More information about Dr. John Dole is available at https://cals.ncsu.edu/horticultural-science/people/jmdole/.

Learn more about the American Society for Horticultural Science (ASHS) at https://ashs.org/.
HortTechnology, HortScience and the Journal of the American Society for Horticultural Science are all open-access and peer-reviewed journals, published by the American Society of Horticultural Science (ASHS). Find them at journals.ashs.org.

Consider becoming an ASHS member at https://ashs.org/page/Becomeamember!

You can also find the official webpage for Plants, People, Science at ashs.org/plantspeoplesciencepodcast, and we encourage you to send us feedback or suggestions at https://ashs.org/webinarpodcastsuggestion.

Podcast transcripts are available at https://plantspeoplescience.buzzsprout.com.

On LinkedIn find Sam Humphrey at linkedin.com/in/samson-humphrey. Curt Rom is at https://www.linkedin.com/in/curt-rom-611085134/. Lena Wilson is at https://www.linkedin.com/in/lena-wilson-2531a5141/.

Thank you for listening!

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Transcript

Curt Rom: 0:00

Welcome to Plants, people and Science, a podcast of the American Society for Horticulture Science where we talk about all things horticulture. I'm the cohost, Curt Rom, from the University of Arkansas, and joining me today is Sam Humphrey. Sam, how are you doing today?

Sam Humphrey: 0:19

Good morning, Curt. I'm doing well. On my way into the house this morning I saw a squirrel and its whole face was yellow from eating tulip poplar flowers. So the flowers are blooming over here and it's been a beautiful spring so far.

Curt Rom: 0:35

Yeah, it's been a beautiful spring. Here too, it was a very early spring. We had almost a record warm February, notably with a record coldest temperature in February, but record warm February. So flowers bloomed early, trees bloomed early. In my research orchards my apples bloomed about two weeks earlier than what we would say is average. It's one of the earliest blooms I've ever seen. I know you work with strawberries and I always think about strawberries in the spring. Tell me about how your work is going.

Sam Humphrey: 1:08

My work's going all right. I've been doing a lot of writing, but, yes, the strawberries are growing. This week there was a strawberry field day in North Carolina and, yeah, a lot of good things going on for me right now. Curt, I saw woodchuck yesterday too. That was a highlight of my week. How's your spring going?

Curt Rom: 1:26

Well, spring is going really well. You know woodchucks. I think they're cute animals. I don't want them near my yard or my garden. I think you know this about me. I'm a gardener. I really like it, and so springtime is really special. I'm really busy in the garden. I have a vegetable garden. I have large flower gardens, they're all blooming. But as a professor, spring is also kind of an important time of year and time of year that's simultaneously exciting and stressful. So the semester's winding up, final exams are next week and in just two weeks we have commencement and commencement here. I love commencement because it's great to see our students graduate and move on, whether they're undergraduate students or our master's or our PhD students, to see them moving on, and I really really like that. Interestingly, our commencement is always the Saturday before Mother's Day, which is always a good reminder that Mother's Day is the day after. Now, when I think about Mother's Day, I think about flowers. I understand it's one of the biggest days of the year for giving flowers, gifting flowers to people.

Sam Humphrey: 2:47

Yeah, I remember the first flowers I ever received. Do you remember your first flowers?

Curt Rom: 2:52

You know, I don't know that. I remember giving my first flowers to somebody. It was when I was in high school and I give flowers regularly. I just gifted flowers to somebody yesterday who was recovering from some knee surgery. I will gift flowers on Mother's Day. I'm going to be a consumer and give some nice flowers, you know probably some beautiful spring roses.

Sam Humphrey: 3:23

Yeah, that's a good choice. My favorite are the butter colored like yellow roses that I've seen in stores, and so many of us are consumers of flowers. Many of us remember the first flowers we gave or that we got. But what inspired this episode is I actually didn't know where cut flowers came from, and several members of our podcast team also didn't know where cut flowers came from. So joining us today we have Dr Dole, a professor of horticultural science at North Carolina State University. He got his bachelor's at Michigan State and his PhD at the University of Minnesota. He's a longtime member of ASHS, the American Society for Horticultural Science, and he's even served as chairman of the board. His current research activities focus on cut flowers, including new cultivar evaluations, production, post-harvest and marketing analysis. Dr Dole is also one of the founding members of Seed your Future, a program that teaches kids about careers in horticulture, and he continues to inspire a love of horticulture in young students. Dr Dole, welcome to the show.

John Dole: 4:30

Thank you very much. I'm very excited to be here.

Curt Rom: 4:34

Dr Dole, great to see you again. It's always fascinating for me to have conversations with you. I have a question before we get going Should we call you Dr Dole or would you prefer for this conversation we call you John? John, please? Okay, that's great. Call me Curt. And of course, Sam is Sam so good that we're all on a first name basis here. So I've known you most of your career and you've always had this passion for flowers. Where did your passion for horticulture and flowers begin? How did it start?

John Dole: 5:09

You know, I grew up in an area of the country with a lot of horticulture and that is West Michigan. I grew up a little west of Grand Rapids. It is an area with a lot of fruit production. I grew up picking strawberries and raspberries for money. We were paid by the court for strawberries and paid by the pint for raspberries, and then later in the season we picked apples. It was also a very flower growing area.

John Dole: 5:36

A lot of Dutch settled in West Michigan. They found the environment there somewhat similar to the Netherlands and they brought with them their love of flower growing. So there's a lot of flower production in the area. I grew up next to my grandparents and my grandparents were hardcore gardeners and they, you know, they were Dutch and they put a lot into their garden and I really had a lot of fun helping them out and, you know, planting and taking care of the flowers in their garden. And then, when I got old enough, I started doing a garden in my, you know, I started taking care of the family garden, which was vegetables, and even then, even though we were focused, you know, the garden was for vegetables. I always made sure we had a lot of flowers in that. Early on I remembered finding seed catalogs and just being enamored with seed catalogs, all the stuff that was in there, and, just you know, getting permission to order every year After a couple of years my parents just let me go and I ordered whatever I wanted to. So yeah, it's right from when I was a kid.

John Dole: 6:51

Oh, one more thing I grew up next to, on the other side of our house, was a farm market stand. Mr Buecher ran the stand and he would grow vegetables, he would grow flowers, he grew gladiolus. So this was back in the days when you couldn't go to a grocery store and buy gladiolus but you would go to a farm market stand and buy them. So I would help him plant the corns in the spring and then I would help him harvest the flowers and then he would sell them at the stand. In fact my parents say I started when I was eight years old, going over to my neighbors and quote unquote helping At the beginning. I'm not sure how much I helped, but anyway he sort of took me under his wing. So I'm just completely surrounded by horticulture and flowers when I was a kid, which was great by horticulture and flowers when I was a kid, which was great.

Curt Rom: 7:45

You know I was talking about Mother's Day and I know that's a big day for bouquets and gifting flowers and horticulturally we use the term cut flowers. And the other day I was teaching in a class about gardening and gardens and I used the term cut flowers and I had these blank stares from students. I think we might know what that is, but why don't you, as the expert, tell us? When we use the word cut flowers, what do we really mean?

John Dole: 8:16

You know that's a good question. It's a question that's actually been changing a lot over the years. You know, originally, cut flowers well, cut flowers have been with us pretty much since the beginning, you know, as long as there were plants with flowers and as long as there were people, there were people cutting flowers and using them. You know, the historical record of cut flowers goes way back. You can see them in some of the drawings. You know, even with the Egyptians, you know so. Cut flowers have been with us forever. You know, even with the Egyptians, you know so. Cut flowers have been with us forever.

John Dole: 8:46

Really, it's anything ornamental that we cut and use and bring into our homes for, you know, to enjoy them and to liven up our lives.

John Dole: 8:56

The original cut flowers were flowers that folks cut from their gardens or they cut from the fields outside the village or whatever.

John Dole: 9:13

Now, when we say cuts, a lot of times we're talking roses. Roses are the most important cut flower in the world in terms of sales volume, but there are just so many other cut flowers that are out there and, to be honest, we sometimes talk about changing. For example, I work with the association, especially cut flower growers, and over the years we've talked about changing that, because so much of what we grow and sell is more than cuts. We grow cut foliage, we grow cut stems, we grow cut berries, you know, big long winter berries, big long beauty berries with those gorgeous purple berries, you know I mean, there's just so much we grow that's other than cuts. But you know, getting back to it, it pretty much is anything that we harvest and bring into our homes for enjoyment or that we give to people for enjoyment, or that we give to people, you know, whether it be birthdays or whether it be weddings or some of the other events that we mark with cut flowers.

Sam Humphrey: 10:11

That's incredible. I didn't. I wasn't thinking about the cut foliage and the cut berries. I it is so much more broad than I had in my mind, but for for the purposes of this question. Mind, but for the purposes of this question, I'm curious. I grew up in Orlando where we have this beautiful garden with tons of different cultivars of roses. So much variety, but none of those roses look like what you would buy in the grocery store. Are there longer stems on cut flower cultivar? What are the differences between what we're used to seeing in the wild and cut flowers?

John Dole: 10:50

Yeah, that's great. Yeah, the rose breeding and rose development has gone in different directions and there's one whole focus on cut flowers. Those tend to have long stems. The breeders try to minimize the number of thorns. They try to maximize the vase life. They generally have a well-formed head that opens up slowly. Now in the United States we like medium to large size roses. The Europeans tend to like smaller roses with smaller heads. The Russians for some reason like the biggest roses of all, which tend to be grown in, like Ecuador. So there's a little bit of variation there, even within the cut flower industry. Within the cut flower industry, some of the other characteristics, hopefully as disease and insect resistant as possible. Our growers need them to be productive.

John Dole: 11:52

There's a lot of discussion on fragrance of roses, and roses vary quite a bit in fragrance and even in the garden you will see that they vary somewhat.

John Dole: 12:04

I would say that many of the most popular cut flower roses are not as fragrant as some of the classic garden roses. It's not that they're not focusing on fragrance, it's just that there's so many characteristics that it takes to make a successful, profitable cut flower that fragrance doesn't always make it to the top of the list, so to speak. But there is more focus now on bringing in some of those garden roses into the trade and we see a lot of local growers in the United States producing all sorts of just gorgeous fragrant fun what we call garden roses and selling them as cut flowers. Many of them they do not have as long a vase life, they do not have as long of stems, but for what we love roses you know the fragrance and the lushness they certainly do meet that criteria. So the United States is bringing back roses in a different form. We also use rose hips, the fruit that roses produce. There's a whole series of cultivars that are developed just for harvesting for the hips. So that gets back to the fruit that I mentioned early on.

Curt Rom: 13:21

So yeah, yeah, pretty much, the breeders are going in different directions depending on the use. John, you've made me curious by some things that you said. You said the Russians get their roses from Ecuador, and then you talked about local production. Tell us a little bit more Elaborate on this. Where are most cut flower production located, located and where do they grow various types of cut flowers for various markets? And I know that you published a recent survey about cut flower production, so maybe tell us about where they are produced and some of the challenges that these producers have.

John Dole: 14:01

Sure, Now, in the United States, the bulk of our cut flowers come from Colombia and Ecuador. There are dozens and dozens of countries from which we get cut flowers. You know we get orchids from Thailand and Malaysia. You know we still get quite a bit from the Netherlands, which is the flower growing and flower growing handling country in the world. But the bulk of our cut flowers come from Colombia and Ecuador, and those are mainly the large-scale cut flowers such as roses, carnations, chrysanthemums, ulstameria. Those are probably the top four, but we do get many, many other species from those countries.

John Dole: 14:47

Having said that, for cut flowers to come into the United States, they have to be harvested, they have to be boxed, they have to be shipped. You know Mexico can ship them across the border on a truck. We get a lot of cut flowers from Canada as well. Those can come on a truck, but for the most part a lot of cut flowers have to be put into boxes and then shipped on an airplane or, more recently, more increasingly, they're shipped via ships, ships, Ships. There I'm going to end up with a tongue twister here in a minute. But regardless, they have to tolerate that process. They have to tolerate the harvesting, the handling and then the packaging and the shipping. And many flowers do. Roses are very, they handle that just fine. Carnations even better.

John Dole: 15:38

There's a lot of flowers that don't, and so those are grown locally. One of the most commonly grown cut flowers it's not the most important, but it's most common is zinnia. Zinnia has a whole broad range of colors. You know it's a flower that some people think about as their garden flower. They love it. It's just been popular for many years. It doesn't handle being put in a box. It will not handle being shipped very well at all. So dahlia is another one. We have hydrangeas.

John Dole: 16:09

We have so many cut flowers that we grow that simply do not fit the model of being grown in large quantities and being shipped and also being sold. Now those big growers are generally selling through the big retailers. That would be, you know, the grocery stores. That would be some of the wholesalers. That would be places like Walmart and Target where they sell flowers. So we have so many other flowers that don't fit that production model and it's been a lot of fun watching that grow and develop. People buying flowers at farmers markets, people buying flowers from florists that cater to local growers. We have a lot of farmer florists that are growing and selling and designing with their own flowers. So I think I wandered a little bit off the question there. But anyway, thanks for giving me an opportunity to talk about that.

Sam Humphrey: 17:04

Now I plan actually to go to the grocery store later this week, so I'm going to do some research before I get there so I can arrive and say, oh, maybe that one was grown locally and oh, that is so interesting. I didn't think about the diversity there. So for roses specifically, and for these flowers that have to be shipped long distances, what sorts of treatments, what can we do to?

John Dole: 17:34

increase the shelf life of those flowers. Well, there's a whole bunch of things you know, and that too you know. That's my research. Try to encapsulate all that Let me focus on from your point of view. What you would want to do First is look for fresh, pull them out of the bucket if they're in a bucket in the shop and then check the water just to make sure the water is nice and clean. Hopefully they're using some sort of floral solution. The floral solutions do help make them last longer. There are several products that have been developed just for roses and we've tested them and they do work. And that's on the production and the handling side. So you've got this nice, fresh bunch of flowers. You know, if you're going to be doing several things that day, get the flowers near the end so that they don't sit in the car, but if it's just gone to the grocery store or the florist, then go ahead and get them, bring them home. Recut the stems, take about an inch off. We've done work on that. It really does help. When you recut the stems, get a nice vase. They will give you a packet of flower food. Follow the directions.

John Dole: 18:42

Usually it's either a quart or a pint of water and then mix it up. I usually do warm water because it dissolves quicker. Basically it's sugar with various other additives into it to reduce the pH and to keep microorganisms from growing into it. To reduce the pH and to keep microorganisms from growing. You know we're in the south here, so we do sweet tea. If you've ever had a glass of sweet tea that you've forgotten somewhere outdoors or in the house, you will see very quickly all sorts of gunk growing. Okay, that gunk is bad. Okay, we wouldn't drink it. So we don't want our flowers to drink it. So we want to make sure that our flowers have good, clean water with no gunk in them. And the compounds that are in that packet of flower food keep that gunk from forming. And we have done all sorts of experiments, some of which I really don't want to think about, talking and looking at the gunk that is produced in these solutions.

John Dole: 19:40

So use that packet of flower food and then go ahead, put them in Now. The roses will probably drink up that first solution within a few days, depending on how they're handled, maybe in a day or two. Then just go ahead, recut the stems one more time and put them in fresh flowers. We call that first solution the first drink. If that first drink is a good flower food, then that will generally make them last a long time. Then you can use just clean water from that point on and you don't have to worry about I'm going to put in one more plug here. Don't have to worry about I'm going to put in one more plug here If you don't have that packet, a good home remedy and it's about the only one that works, because if you go on the Internet you find 50-50 with water and that will work for most flowers to help them last long. So if you're cutting flowers from your garden and you don't have the packets of flower food, use the soda and water mix.

Curt Rom: 20:53

Regarding that shipping. So you told us what to do at the consumer level. What's the state of the technology for commercial producers that are producing it and having to ship it? How long is the supply chain usually from the time that they're cut on a farm to the time they might get to a floor store or retail, and what's the technology that helps them be preserved during that supply chain?

John Dole: 21:20

The supply chain is quite variable for the flowers that are grown locally. If you go to a farmer's market on Saturday morning, chances are those flowers were cut the day before, they were hopefully put in a cooler and they were put in the buckets and then they're brought to the farm that morning and they were put in the buckets and then they're brought to the farm that morning. If you go to a farm, you know some farmers markets on like Wednesday evening, chances are some of those flowers were cut that morning, you know. So that's the shortest and literally they're put into buckets, oftentimes in the field, and sometimes they stay in that bucket. Other times they are pulled out, you know, and a bit sorted and processed and brought into, you know, and brought to the farmer's market. So that's the shortest one and that's definitely the freshest, and so for folks who really want fresh local flowers, you just can't get anything better than that. You know they're just wonderful. The longer chains occur with some of the more far-flung production locations, you know. So Columbia, the flowers should be generally harvested in the morning, although roses if it's a warm day they might harvest roses two times a day, maybe even three times a day, because they like to cut them just at the right stage, before they get too open, and so. But generally roses and other flowers are cut in the morning and then they're brought in as soon as possible into the processing area. The lower foliage is removed, they're bunched, the stems are recut, they're put into a hydration solution to help them take up water, and then they might be put into a holding solution, which generally has some sugar in it to help them hold for a while. Then the shortest is. They will then be boxed the next day after they've been cooled down.

John Dole: 23:15

You know flowers are like fruits and vegetables. We want to get the field heat out if it's warm. You know we want tomatoes to cool down. We want, you know, the beans to cool down. So we do the same thing with flowers. We get the field heat out as soon as we can to slow down the process. Then they are sleeved, bar-coated for the grocery stores or whatever, and then put in boxes. The boxes are palletized, those are brought to the airport and put on the planes. There are special planes that are specifically used for making sure that the flowers get to the United States. If they are put on a boat, it's the same process, it's just that they're taken to the port and they're put in containers which are held at a very constant temperature of about one degree C and then or even a little bit less, if possible and then shipped off to the United States or Japan or wherever they're going. So that's the longest and that's the shortest.

Sam Humphrey: 24:13

That's amazing. I want to drill down into this a little bit. So is it warehouses? Are these greenhouses? What does it actually look like if you were to stand there and follow the flower?

John Dole: 24:25

Right, you know, if you're a flower grower in the United States, chances are pretty good you're growing a lot of stuff in the field.

John Dole: 24:34

You might be growing stuff in a high tunnel, and then we do have some of the folks that are growing in regular climate-controlled greenhouses, you know, with pads and fans and everything like that. If you're a flower grower in Colombia, chances are you're growing in very large greenhouses with big vents, very large greenhouses with big vents. The climate in Colombia and Ecuador is very close to optimum, so they don't do much manipulation of the climate. They don't have to, except when the weather gets a little wonky, which it does occasionally, in which case they might close up the vents. So these are very large greenhouses with not much climate control other than vents that they open and close to try to regulate the temperature, and so they're spectacular. You know, large greenhouses, lots of flowers. So again, that gives you the range everything from field to high tunnels, to tunnels with some climate control, to big greenhouses with no climate control, to big greenhouses with full climate control. A lot of our tulips come from greenhouses with full climate control.

Curt Rom: 25:49

In the shipping once they're cut in their ship. So you bring down, you take, get out the field temperature. Is there any use of growth regulators or any other atmospheric changes? Do we use ethylene inhibitors, 1-mcp or treatments like that to slow down the flower maturation during the supply chain process?

John Dole: 26:14

We sure do, and you mentioned some great stuff, so I know you know about post-harvest. Yeah, let's start with temperature. That's by far the most important factor. We need to get the flowers as cold as possible, and as cold as possible for the species, because we grow a lot of tropicals as well, some of which do not like it cold, or let's just say 55 degrees is cold for them, so it's as cold as possible for that species.

John Dole: 26:44

For example, we grow basil. Basil makes a really great cut foliage for bouquets, it adds fragrance and basil is notoriously cold sensitive. So we don't store basil in the cooler with other flowers. So we don't store basil in the cooler with other flowers. Most of the flowers we like to store them at around 33, 34, 35. Having said that, most of the coolers tend to be warmer, which is something I try to work on with the growers. But anyway, we try to store cold and we try to maintain them cold all the way through. This is known as the cold chain, making sure that they stay cold from the first point that they get into the cooler until they really are sold to the consumer or sold to the customer. The more we can keep the cold chain completely cold, the better the quality and the longer the vase life for the customer. Completely cold, the better the quality and the longer the vase life for the customer.

John Dole: 27:40

Some of the other things we do the flower foods we talked about, you know these are floral solutions that have an antimicrobial agent to keep the gunk from forming, an acidifier. We've done work on this. Flowers take up acid water easier than they take up alkaline water, so acid helps to keep the gunk from forming, but it also allows it to go up the stems more easily. And then, finally, sugar. You know we all you know cut flowers. They're not in a greenhouse, they're not photosynthesizing much anymore. They need for us to provide them with an energy source and that is various types of sugars.

John Dole: 28:22

And then, finally, you mentioned STS and 1-MCP, and I will mention that 1-MCP was developed right here at North Carolina State University with Ed Sisler. You know that very well, ed Sisler and Sylvia Blankenship. Ed Sisler and Sylvia Blankenship. Sts and 1-MCP block the receptors for ethylene, which prevents the flowers from moving along in their senescence process. Many flowers are not that sensitive to ethylene, but a lot of flowers are, and those flowers are generally treated with one or the other of these anti-ethylene agents. There's a handful of other chemicals that are used, some of which are endogenous, that help to keep the foliage green. But yeah, those are the main ones.

Curt Rom: 29:10

So STS is silver thiosulfate, an ethylene inhibitor. It blocks the production or the reception.

John Dole: 29:17

Yes, and then 1-MCP is 1-methylcyclopropene. You can see why we say 1-MCP, right.

Sam Humphrey: 29:25

That's a lot of research. That's happened for decades. It sounds like. It sounds like we've made a lot of progress in keeping these flowers alive. Thank you for that, john. I'm curious, though what is the cutting edge? What work is being currently done and focused on that you find really exciting.

John Dole: 29:43

Oh golly, there's a lot of fun stuff. I will start with just new species, as much as we have a lot of species already, much as we have a lot of species already. Floriculture is where fashion meets agriculture, and what I mean by that is, you know, we have all the issues of agriculture, which are, you know, growing it, growing it on time, growing it high quality, pest diseases, dealing with the weather, even in a greenhouse, completely climate controlled greenhouses. When it gets hot it gets a little harder to control the temperature. So we have all the issues with ag, but we also have fashion. You know which color? You know various flowers become fashionable. You know Martha Stewart. You know she's been around forever and she's still. You know, southern living. If something shows up in one of the lifestyle magazines or in one of the lifestyle television shows, suddenly there's people that are wanting it, and so we have to deal with that. We have to deal with all the variability of you know, and all the diversity. So I'll go back to one of the things we have been worked on for years, and that is bringing new species, new cultivars, new colors to market, and there's just some fun, just incredibly fun stuff.

John Dole: 31:05

This industry is very entrepreneurial. I swear that they will grow, cut and harvest and sell just about anything. I'll tell one quick story. Years ago I was giving a talk and I made this statement and I said something about well, except for dandelions, you know. And then one lady in the back she rose her hand and she shook it vigorously and she said that in the I guess it was in the forties and fifties you could find little bouquets of dandelions being sold. So I can't use dandelion anymore. I have never seen poison ivy being cut and sold as a cut. So that one I'm pretty sure about.

Curt Rom: 31:49

Yeah, I'm glad about that too.

John Dole: 31:52

Some of the other things. Let's go completely on the other sides of the research spectrum and that's some of the genomic work being done To take a look at. You know, we've got CRISPR now where we can knock certain genes out some of the ethylene sensitivity genes you know, working on that, some of the genes that cause senescence, you know. So there's some great work being done to slowly tease that apart and then do some of the CRISPR work to make flowers naturally last longer without having to do all of some of the things that we have to do. In the middle is some of the physiological work, and I'll put in some of the stuff that we're doing.

John Dole: 32:34

We just finished a whole series of experiments dealing with gently freezing flowers, holding them at temperatures just below freezing or just below zero degrees C. This was kind of a bucket list project. I've always wanted to do this. There's been some work from the 50s that showed that you could freeze flowers and get them to last longer, post and fissure, and so I've always wanted to replicate this and then, luckily, I was able to get a project. Nathan Jahnke, who's with Ball now he's a PhD student was able to do it, and Jen Kalinowski, research associate they were the ones who were able to do this stuff and, yes, it turns out you can freeze flowers and you can make them last longer. It works especially well with tulips, but it also helps with peonies, roses and a few other things. So, yeah, we're very excited about that. That's very new. It'll probably take a while before it gets implemented in the industry because it's going to take some changes there, but yeah, when you say gently freezing them, do you mean like you take four hours to bring the temperature down?

Sam Humphrey: 33:44

What does that look like?

John Dole: 33:46

More. I meant gently, because we're going 31 degrees. That's most of our work was being done. I think further work would show that some of the flowers could be colder, like 30, maybe even 29. So it's not like 20 degrees, you know. So it's just below. Freezing Really slows the physiology down, slows the ethylene sensitivity down and allows them just to be held for much longer.

Curt Rom: 34:15

You know, that makes complete sense in my own experience as a gardener, because my daffodils, my tulips, my peonies all bloom before our last frost and they're not. They're much less sensitive to frost than the apples that I work with which, you know, 28 degrees is a disaster. 28 degrees is a disaster. The daffodils they might look a little frozen, but as soon as the temperature is up they come back to life. That's great. Taking that kind of observation to science, john, that's really fantastic.

John Dole: 34:52

Well, we started with peonies for exactly the reason you mentioned is that cut peonies are very tolerant of cold in the field and they're primarily field grown, and also cut peonies are just beloved. You know, that's one of the flowers that have just gone through this huge resurgence, but they only grow and flower in any one location for just a few weeks. They don't grow that. They're not that amenable to greenhouse production, and so being able to store cut peonies has really been kind of very important for that industry as well. So we pick peonies because of its production issues, but also because it can tolerate the freezing, and then we went on to other flowers that could tolerate, such as iris and tulips. So that's exactly why we started with those flowers.

Curt Rom: 35:47

I look forward to reading your publications about that.

Sam Humphrey: 35:50

Something you said, John, caught me really interested. You mentioned translating your science to the people in the field who are actually transporting and growing these flowers. It reminds me of a discussion we had last year on the podcast with Dr Teresita Amor. She is a orchid and anthurium breeder in Hawaii and she talked about how she has to connect with the growers and figure out what the growers want and get a lot of feedback from them. How do you connect with people in the industry?

John Dole: 36:23

Yeah, you know, we do, especially this industry where it's so diverse. The association, especially Cut Flower Growers. I'm executive director for them and have been for quite a while. I started as a regional director in 1991 with this group. It's just a fun, fantastic group of people. It's about a little less than 3,000 members across the United States, canada and even a few beyond that. The meetings they give farm tours, they give meetings, just getting to know and meet with the growers and hearing what issues they're dealing with. I also try to get out to farms, I try to visit places you know some of the wholesalers, some of the florists, just to get an idea of you know what's going on, what are their issues. What do we need to be addressing, both in terms of the research but also in terms of the extension? How do we get the research out there? And then even what to incorporate into the classroom.

Curt Rom: 37:25

Well, john, during my lifetime, and probably yours, we've seen such a tremendous change in the cut flower business when I was growing up, or probably even when I was in college business. When I was growing up, or probably even when I was in college, you would only see flowers at florist shops. They were very expensive. They weren't the commodity that they are now. I mean, our access to getting flowers is so tremendous and I think it's the science of scholars, scientists and those that can translate that information to our growers. During your career, you've really had the ability to change and provide access to those of us as consumers to have flowers essentially on our table every day. I know we think about flowers at Valentine's and we started this conversation thinking about Mother's Day, but flowers have really become a unique commodity because the science that's been created for them.

John Dole: 38:25

You know it's like a lot of our crops. You know if we could just let folks know how much work and how much cool stuff goes into. You know getting a dahlia to our table, getting a rose to our table, getting a strawberry to our strawberry shortcake. You know getting lettuce. You know there's just our field is so cool in so many ways and the fact that we then get to enjoy it, you know, whether it be we get to eat it or we get to visually enjoy it. Yeah, yeah, we have a cool field, you know, and it's been great, great fun. I wish everybody had the opportunity to work in such a good field.

Sam Humphrey: 39:12

So for students who may be listening, they could be undergraduates, they could be high school students just exploring what's out there. What advice would you give someone who might be interested in cut flower research or ornamental plant research?

John Dole: 39:27

Yeah, that's very good. Internships, that would be the best thing, even if it's somebody in high school, whether or not they do an internship. But flower farming has spread across the United States. There's lots of farms. Most towns now have, you know, one grower or so producing flowers and so there should be not too far away someplace to work. You know, if you're a high school, flower farmers need you know they need folks to help out with the production and the harvesting and you know, and doing all the things involved with getting the flowers to sale. So high school students can get jobs pretty readily. College students can also get jobs. They can also set this up formally as an internship. Most of the flower growers will have some type of internship, which can really help them get some experience.

John Dole: 40:29

Then, in terms of the classwork, you know the basic horticulture courses. I would take a plant materials course, one or two of those, to learn the variety of species. You know I've mentioned the diversity of cut flowers several times here. We put together a book of post-harvest of cut flowers and in that book we put all the species that we knew at least a few folks were growing and it was well over 200 different genera that are being grown and sold as cut flowers. So students learning which ones those are, if they have a post-harvest class at their university, that would be great. That'd be icing on the cake A good floriculture production course. So take the basics and then add in some of the floriculture production and get as much experience as you can, whether it be with a grower, a florist, a wholesaler or whatever you can.

Curt Rom: 41:30

Well, john, you know this has been really fascinating, I sort of. I mean, I've been in horticulture a long time but I've learned a lot more about the details of the supply chain. I'm really interested, having worked in local foods, the way that you've been emphasizing local floral production. I've seen that at my market too. Is local floral production in the United States an expanding area?

John Dole: 42:01

It is. It is. You know, flower production has been around for well forever, to be perfectly honest, when you take the broad view. But starting in the 2000s and around early 2010, 11, 12, and around early 2010, 11, 12, local became a big deal and flower production has just soared and we're thrilled with that. It's given a lot more folks an opportunity to start businesses and to get into flower production. But yeah, local is a big deal. The membership of the ASCFG was around anywhere from 500 to 700 members for many, many years and then, starting in around 2012, with the interest in local, it went up and, like I said, it's close to 3,000 members now and a lot of that is because of the interest in local production.

Sam Humphrey: 42:55

This has been fantastic. John, Thank you so much for coming on the show.

John Dole: 42:59

I've enjoyed it. I've just absolutely enjoyed it. Thank you all so much.

Sam Humphrey: 43:03

For our listeners. If you'd like to read more about this topic, you can check out John's paper South and Central America Cut Flower Production and Post-Harvest Survey, which is published in one of the open science peer-reviewed journals published by the American Society for Horticultural Science. Links to this article and a few more by John Dole will be provided in the show notes. John also writes frequently for the Association of Specialty Cut Flower Growers, so we will include those links as well.

John Dole: 43:31

I'll add real quick there's another article that details the domestic industry in the United States and Canada.

Curt Rom: 43:38

Thank you for that information, john. Sam, this has just been fascinating to me and it's timely, knowing that we're coming up with one of the biggest flower days of the year, with Mother's Day For our listeners. If this interview resonates with you, we recommend that you consider renewing your membership or joining the American Society for Horticulture Science. Undergraduate students have a complimentary membership for the entire time they're an undergraduate student. Graduate students receive one year complimentary and then a highly discounted membership. But that's the way to connect to the science is to join the American Society for Horticulture Science. To connect to the science is to join the American Society for Horticulture Science and then you can be part of the interest groups like the Floriculture Interest Group or the Post-Harvest Interest Group. If you'd like information about the American Society for Horticulture Science in general, go to our website, ashsorg. Well, sam, john, that kind of wraps up today's episode. Thank you both for being here and I want to thank our listeners for tuning in. Sam, it was really great to visit with you today and I really enjoyed this interview.

Sam Humphrey: 44:52

Oh, I'm so excited for this spring and for cut flowers and for our future episodes. This was Samson Humphrey and Kurt Rome talking about cut flower production and we hope you join us again, Thank you.