creating living willow structures, with michael dodge
I VIRTUALLY NEVER promise “fast and easy” in gardening, which involves worthwhile hard work and patience, but here’s the exception: You can create fast-growing living structures such as tunnels, domes, privacy screens and even deer-proof fences with living willows. I asked Salix expert Michael Dodge to show me how.
A little about Michael:
“That’s Michael Dodge,” I say, when I show people around the fall garden, as we pass a large group of show-offy, yellow-fruited Viburnum I enjoy all fall into winter. V. dilatatum ‘Michael Dodge’ is truly a standout plant.
But the original Michael Dodge, the one that great shrub was named to honor, is a well-known British-born plantsman whose career has taken him from Royal Botanic Gardens, Kew, to New York Botanical Garden, to Winterthur in Delaware, to White Flower Farm, where he was director of horticulture and of the famous catalog, spending 26 years there till 1997.
Michael moved on to further adventures, many of them with his camera in hand, but most recently it all led to his version of retirement: collecting and then disseminating 250ish species and varieties of the genus Salix, or willow.
His company, called Vermont Willow Nursery, looks more like a full-blown nursery to me than retirement. (Update: In 2020, Michael announced that he would seek to transition the nursery to new ownership, and it is for sale). We chatted on my public-radio show and podcast in 2015, discussing willows for a range of uses, from getting the garden off to extra-early bloom, to crafting living structures (top and below, a dome at Michael’s home, in active growth and before leafing out), and taking a stern hand when pruning.
Plus, at the bottom of the page: Michael’s secret “twine” for use when tying up woody plants. (Why didn’t I know about this decades sooner?)
listen/read: willow q&a with michael dodge
Q. You know a lot of genera of plants from your long career in horticulture…so why willows now? How did you get to the willow stage of your career, Michael?
A. It’s very simple: When we moved to Vermont, we bought a house on 50 acres of wet clayey-loam soil.
Then we went to the Montreal Botanical garden, which is 60 miles from us, and there was an exhibition of living willow structures—and we had no knowledge of them until that point. We were just blown away by the display, as we had no knowledge of this art form. I was immediately addicted to willows. We went to England the next spring, and visited several willow nurseries, and learned all about willows.
Q. When you say “we,” you mean you and your wife, yes?
A. Yes. She’s not a horticulturist, and she thinks I’m insane.
Q. But she loves you anyway? [Laughter.]
A. Oh, of course.
Q. So it was those acres and acres of wet clay that said to you, “I need an ambitious grower; something that’s cooperative.”
A. There were a number of native willows growing on the property, and at that time I could not tell one willow from another. Later I discovered that there were seven different species, once I studied them.
Q. If you had to give us the elevator pitch on the genus Salix, the quick promotional pitch, what would you say about it—besides that it includes plants that have a tolerance of wet clay?
A. Willows are exceptionally easy to propagate and grow. They’re also one of the most diverse species of plants in the temperate world. They grow into immense, 100-foot trees, and last summer I climbed Mount Adams in New Hampshire to see a willow that was only 1 inch tall.
Q. You’re kidding; an inch?
A. Oh, yes–Salix herbacea.
[Above, Michael studying Salix x peasei (herbacea x uva-ursi), the rarest willow in the United States, and only found in that location. Photo by Julia Kozovkina PhD, University of Connecticut.]
Also, willows have very colorful early flowers, providing pollen and nectar for bees that come out early; many have colored stems for the winter. Some have golden leaves, or variegated leaves, or beautiful, shiny leaves that look like cherry laurel [Prunus laurocerasus]. When you can’t grow broad-leafed evergreens as we can’t in northern Vermont, except for a few rhododendron, something that looks like cherry laurel is very welcome.
[For glossy-leaved choices such as S. pentandra ‘Patent Lumley’, shown, look under “Showiest Foliage” on this page at Vermont Willows.]
Q. We’ve mentioned willows for wet clay, and willows on top of a mountain in New Hampshire, but are there willows for all climates, or do they not “do” in some zones?
A. They’re mostly temperate; there are native willows that grow in all states except Hawaii. Every other state has willows—even Florida, California and Arizona.
I’m speaking from New Mexico right now, and willows do grow here. There are both native willows, perhaps 20 kinds, mostly on the mountains; also you see European species and Chinese species growing in people’s gardens. You see weeping willows here that are 40 or 50 feet tall–in New Mexico, with just 10 inches of rain a year. How they survive, I do not know.
Q. The golden weeping willow that’s the common tree we see—where is that native to?
A. The one that you see mostly is actually a hybrid between Salix alba (from Europe) and Salix babylonica (from China).
Q. I actually love seeing them in late winter, before anything else has leafed out, with their yellow twigs. I’m not as crazy about how messy big old weeping willows are in a garden setting, but in late winter…
A. They do have that reputation for messiness. But when you’re driving through New England especially, you see these golden trees, and everything else is either green or brown or gray, and those are the brightest thing around.
So you can grow willows all over the country, especially in the northern half.
Q. You have a whole range of suggested uses for willows on the website. What are some that seem to draw your customers most? I first added willows for their colorful twigs—like I do the twig dogwoods—and then for very early flowering for sustaining the first pollinators awakening in my Zone 5B area.
A. One of the most frequent things that bring people to us: for fences, fedges and screens. They want to block out their neighbors, or block out something ugly, or prevent the deer from coming in. Some of the willows are so bitter to the deer that they won’t eat them: Any Salix purpurea variety, for instance, is inedible to deer. [Salix triandra is another deerproof choice; most willows are at least deer-resistant.]
Q. What a great characteristic.
A. It is. And I also get a lot of requests about what are the most colorful varieties or best varieties for basket-making, and not only from basket-makers but there is a whole plethora of artistic uses that I am just blown away by.
Q. Some are good for honey production, too.
A. Willows have male and female flowers on separate plants. The male flowers [left] have both pollen and nectar; the females just have nectar. Bother male and female plants provide food for bees to make honey with.
Q. Are the male flowers showier?
A. Generally they are, though in some alpine species, the female flower after she’s been pollinated is much showier.
Q. When I have more than one plant of a species, I’ve sometimes noticed a difference in flower size, so I might have both boys and girls. I’ll have to look closer this spring.
A. If they ever turn yellow, and you brush them and your hand gets yellow, you know that’s a male.
Q. So that’s the easy way to be sure; you don’t have to be a scientist to figure that out. [Laughter.]
A. A fedge is a word that’s halfway between fence and hedge. It’s using willow rods—an unbranched stem of willow that has been cut anywhere from 6 feet to 16 feet long—that are stuck in the ground, then interwoven to make a diamond pattern [recently planted diamond fedge, above]. A fedge can also be planted vertically, so the tops intertwine, to create the structure about it.
Q. If I plant them on a bit of an angle [above], they crisscross and make this diamond pattern…
A. …and where they cross, you tie that for support.
Q. Or if you go straight up and down you tie the tops; I see.
A. With willows, you can never bend the tips down below horizontal, or the tips will die. But if you bend it down all the way and stick in the ground, it will root at both ends.
Q. [Laughter.] That’s a crazy-looking thing–the Mobius strip of plants.
A. Or you can use it to create a little tunnel for little people, if you stick both ends in the ground.
A. Yes, we sell cuttings and rods, not rooted plants. I didn’t want to get into that, which would mean storage facilities and so on.
Q. And after all, you’re retired. [Laughter.]
A. Yes, I am totally retired.
Q. What’s wonderful is that these are such easy-to-root plants that you can even stick in the ground a 14- or 16-foot rod and it will root.
A. If you cut down a willow tree down that’s 20 or 30 feet tall, and lay it in water, it will produce roots along the entire length of its stem. The entire plant is capable of rooting.
Q. Crazy, isn’t it?
A. It contains something called Salicylic acid, from the genus Salix, and that was the first rooting hormone ever developed.
Q. My friend Ken Druse, the garden writer and photographer, always used to make what he called willow water. He’d put willow twigs in a jar of water, then when he had other things he needed to root, he’s use the willow water. I don’t know if that’s true or false, but it’s what he did.
A. Oh, yes, that’s how it all started with rooting hormones.
Q. So let’s talk about more willow structures. A nursery near me created a nearly instant living wall between its less attractive areas like the compost and the nursery display garden itself with corkscrew willow; wonderful. A neighbor ordered willow rods and crafted a tunnel two years ago—and even though it was his first try, and he was fearful that it couldn’t work, it’s magnificent, and in such a short time.
A. People want a different look in the garden, and those structures will give you that. They’re amazing—they green up in the summer so you can barely see through them, and in the wintertime you trim them back to the original pattern of the structure. It’s an amazing way of using plant material, and it’s unique to willows—no other plant can root like that.
Q. In the way we imagined making the screen or fedge, would we have two of those and connect them at the top to make a tunnel?
A. You have two parallel rows of rods that you stick in the ground, and tie them together at the top. If you want a really high tunnel, what you have to do because we can only ship 8-foot rods because of Fedex rules: You can let them grow as tall as you want—as tall as your tallest stepladder—and then tie them together at 20 feet, or 15 feet. You can let them grow, then tie them together later, after a couple of years.
Q. You said that before the next growing season, you trim off anything that’s going astray, right?
A. You don’t want to do your trimming and weaving of the side shoots when they are actively growing, because they’re very fragile and soft during their first summer—not at all flexible. They thing is to do it after they’ve hardened in the winter months, just as the sap starts rising and the first smidgens start developing on the plant. That’s the time to do all this weaving of the side shoots, and also when you can see the framework of the structure more easily.
You don’t keep them all, unless you want a very dense thicket. If you want to keep the look of the diamond pattern, you really do want to cut off all the side shoots, or tie the thickest ones in next to the original rods to help strengthen the structure.
Q. Are some species or varieties especially good for the tunnel-making?
A. There’s quite a lot of species that can be used. The most vigorous are things like Salix miyabeana, and schwerinii, and viminalis—which is used a lot in Europe. Unfortunately, I have been unable to grow viminalis until the last few years, until I found one that will grow in Vermont. All the others got terrible pests: every insect, every disease. But I have one I’m listing this year that is resistant to all that, with very long, straight rods, very flexible, and really wonderful.
Q. When we create these structures, do we still get the flowers?
A. By pruning them heavily, unless you use pussy willows—something like Salix chaenomeloides [left] will flower from young growth.
Q. I love that plant.
A. It’s a great one. So you’d wait until it finishes flowering before you prune it then, if you want the pussy willows. There are several—some hybrids like smithiana and hagensis, plus dasyclados and ‘Aquatica Gigantea Corso,’ that have flower very early and very well and are used in structures. Again, they should be pruned after they flower.
Q. So flowering is possible, but requires a slightly different management strategy.
What about some willows for other uses—like earliest bloom?
A. Salix chaenomeloides is always the earliest; there can be flower buds opening in November, even in Vermont, and December. They don’t get any damage, and are still good in the spring. I guess all the fuzz is good insulation.
Q. A winter coat, huh? [Laughter.]
A. So that’s the early one, but ‘Aquatica Gigantea Corso’ is also a great one for flowers, very large flowers. It was developed for biofuels in Scandinavia, but it has three parents and has very large flowers and leaves.
And then there is the pink pussy willow. ‘Mt. Aso’ [left] is by far the most popular willow I sell; I sell hundreds of that. The buds start developing in July and August, so you have these pink buds all winter, and you can have them flowering for Valentine’s Day. Just bring them indoors three days before, and they will be in flower for Valentine’s Day.
Q. Before we finish, I want to get everyone to relax about pruning. These are lusty plants, and grow, grow, grow—suddenly you’ve go this mop and you say, “Uh-oh.” With a regular shrub, not a fedge or tunnel, it’s OK to have a stern hand, right?
A. Absolutely cut them back to the ground—to 1 inch.
Q. Don’t fool around and be wimpy and leave a 2-foot stub—that just makes more of a mess?
A. I cut all of my willows back to 1 or 2 inches, because I want a lot of exuberant growth.
All of the early flowering pussy willows you can do that with, and they will still flower the first year. All the later-flowering ones that flower on when there are leaves present, on old wood—they have to be let go, and let them flower and mature. You don’t prune those as hard, unless you want to produce rods for structures.
Q. When, for whichever kind?
A. Just after flowering.
Q. I admit I’ve got a few that I’ve let go.
A. Cut them down to the ground, and you’ll have lots of cuttings to make more plants or share with friends. [More on pruning with Michael, in this older story.]
Q. Or I could “retire,” and open a Salix nursery.
A. [Laughter.] Or you can take mine on.
Q. How many willows are in the collection now?
A. We sell just under 100, but there are about 250 in the collection. It’s probably the largest collection in private hands in North America, and maybe second only to Montreal Botanical Garden.
I’m moving more into dwarf and alpine willows, and will eventually give up selling the big ones, because nobody else is doing the dwarf types. When I really retire, I’ll get into dwarf willows.
michael’s secret ‘twine’ for willow-tying
OFF THE AIR, I asked Michael what he used to tie the willow structures together. Glad that I did:
“I learned what to use in England then couldn’t find it in this country,” he recalled. “Then one day I was having a screen door fixed and there was a huge ‘aha’ moment. The vinyl cording with ribs on the side was the material. It’s available in every hardware store.
“In England they don’t put screens on their windows, so it’s a specialty product over there.”
It’s a great material, Michael said, because it’s so easy to work with; easy to tie and untie. “One can use a simple single knot with a little pressure; no need to make a double knot unless you’re tying in two rods that don’t want to come together. Then it can be reused over and over again; it lasts indefinitely.”
Looking for information about pruning willows? That’s in this other interview.
prefer the podcast version of the show?
MY WEEKLY public-radio show, rated a “top-5 garden podcast” by “The Guardian” newspaper in the UK, began its seventh year in March 2016. In 2016, the show won three silver medals for excellence from the Garden Writers Association. It’s produced at Robin Hood Radio, the smallest NPR station in the nation. Listen locally in the Hudson Valley (NY)-Berkshires (MA)-Litchfield Hills (CT) Mondays at 8:30 AM Eastern, rerun at 8:30 Saturdays. Or play the Feb. 2, 2015 show using the player near the top of this transcript. You can subscribe to all future editions on iTunes or Stitcher or Spotify, (and browse my archive of podcasts here).
(All photos from Michael Dodge, Vermont Willows.)