stink bugs, shrubs in perennial beds, sourcing plants, damping off: q&a with ken druse
FROM DEALING WITH stink bugs in the vegetable garden to making room for shrubs that lend more four-season structure in the perennial beds (like the twig dogwood above): those are some of the latest Urgent Garden Questions that Ken Druse and I tackled. We also talked about tracking down sources for exceptional shrubs, about preventing seedling death from damping off, about forgotten flower bulbs (oops!), and more.
And like the Postal Service, we did so despite the weather, each of us snowed in at our respective homes, unable to reach the radio studio (where it was also likewise a whiteout) therefore recording via a less-than-ideal remote hookup. Forgive the audio hiccups; a consequence of our weather workaround.
I could best describe Ken as my kooky old friend from whom I have learned much about plants over the years…but here’s the formal version: Ken, an award-winning garden photographer and author of more books than I can count, including “The New Shade Garden” and “Making More Plants,” produced his own “Real Dirt” podcast for 10 years, until summer 2016. The Real Dirt podcast archive and much more from Ken is available on the newly re-launched website KenDruse.com, and still available on iTunes, too.
Read along as you listen in to the February 13, 2017 edition of my public-radio show and podcast using the player below (or at this link).
forgotten leftover bulbs
Q. Linda in New Mexico posted a question on Facebook, and it’s one I get a lot in winter and also in early spring, when people discover forgotten bulbs in their garage.
Ken. Oh, wow.
Q. So she said: “Have I waited far too long to plant 1) garlic, and 2) parrot tulip bulbs? What do I do now? — I’m in Albuquerque NM with a weird winter of both snow and freezing temps and very mild weather. Help please!”
I replied to her (on Facebook): “Can you dig a hole still? And if so, why not—what do you have to lose?” What would you do with the bulbs, Ken?
Ken. Well, garlic I think that’s OK; you can plant them in December and we’re not that far off December. But just like you said, do you want to throw them out, or try? If you can dig a hole and get into the ground to plant those tulip bulbs—or you could try forcing them.
A lot of people who live in, say, California, have to refrigerate their bulbs if they want their tulips to bloom at all. So there is still a chance, I’d say; either plant them in the ground, or pot them up and put them in a cool place (40 to 50 degrees F) until you see shoots, then bring them into a sunny window and see what happens.
Q. I think better than wasting them, give it a try; I agree.
Ken. She might want to soak those bulbs before she plants them, in case they have dehydrated.
Q. And that’s the thing: They start to desiccate, and sort of dry up and shrivel. Of course both things that she is talking about—the tulips and garlic—they want to use the fall, when we normally plant them if we didn’t forget them in the garage [laughter], to set down roots before the ground freezes. That’s what they are hoping to do. So fingers crossed.
striving for 4-season beds and borders
Q. I think Kirsten from Connecticut is on the line with a question.
Kirsten. I am.
Q. Oh, my, it’s a miracle of modern technology—we are all hooked up.
Ken. I can hear; I can hear. [Laughter.]
Q. We’re all hooked together today, Kirsten, because of the snow, by Skype and chewing gum; sorry about any technical stuff. [Laughter.]
I should explain to everyone that you attended my 365-Day Garden Webinar recently, Kirsten, and you had a question afterward that I asked you to share here, too, on the radio. So the context is that you were listening to me give a slide talk about making a four-season garden, and your question came from that.
Kirsten. My question concerns 365-day structure in the garden. How do I mix a border planting so there is structure in the winter, but also space for summer perennials?
Q. Right. So by structure, you mean that you want woody, vertical accents—shapes and forms in winter.
Kirsten. Like small woody shrubs, so I am currently not seeing this flat, barren border in my garden. I am in Zone 6B, so I leave my cutback [perennials] as late as I can, but if I left it too long, it would be flattened by the snow.
Q. I’m down to almost nothing herbaceous here, too. I’m going to let Ken tackle the plant combination aesthetic stuff, but one thing I would say first:
This is a lot harder to do in beds and borders that are narrower, versus very wide, in my experience. I have more success with making sort of a four-season planting when I have more room to work with, than when I have everything cheek-to-jowl.
I’ve noticed that in my widest beds, I do a better job. Some of them are 25 years old now, and they are now more like shrubberies with a herbaceous layer. But when the herbaceous layer collapses after a bunch of snows, as you say, I’ve still got that backbone, or that center spine running down them of the shrubs. If the beds were narrow, I would never have been able to accommodate that, and frankly the beds got wider as the shrubs got bigger—an that’s how I learned that lesson.
Q. How wide are your beds?
Kirsten. I think currently the one in particular is maybe 7 or 8 feet deep, and it’s more of a hummingbird garden—and the only structure now [in winter] is the post that the feeder hangs on, and it drives me crazy. [Laughter.]
Q. So I was having ESP there, and imagining that your beds were narrower than like 12 or 15 feet. Ken, what do you think?
Ken. Twelve or 15 feet sounds pretty deep! I think 8 feet sounds OK, but you may have to remove some of the perennials to get some shrubs in, and then put them back or put them someplace else.
But since you are talking about winter interest, I think some of the colorful twig dogwoods and willows would be great. One of my favorites is the Cornus sanguinea ‘Midwinter Fire,’ which has sort of sunset-colored twigs, and you cut it back every other year. You cut back the oldest wood, so it would be 3 to 4 feet tall.
And there are a lot of willows with colorful bark that people seem to ignore. One is Salix alba variety vitelinna ‘Britzensis,’ which is the coral bark willow—a kind of white willow. I know it’s a terrible name.
Q. It is beautiful.
Ken. It is a cutback plant, too, and will grow to 5 or 6 feet tall, and is very easy to grow. And there are deciduous shrubs [that would fit with perennials in a border], like Weigela and Deutzia and Hydrangea, but you’re looking for winter interest. So I think some evergreen shrubs—you could do some vertical evergreen shrubs. [Photo above by Ken Druse, of New York Botanical Garden perennnial border with columnar evergreen ‘Graham Blandy’ boxwoods.]
If it’s in a lot of sun you can use some of the upright junipers in your Zone, or you can also use mounding junipers. And if it’s a little shade, I think some of the boxwoods are great as those vertical accents. Margaret, you and I talked about some of those fastigiate or columnar plants like Buxus ‘Graham Blandy,’ and ‘Fastigiata’ or ‘Dee Runk.’ And they do take some shade, and certainly give you year-round structure. [More on these columnar plant choices and using them in the garden.]
Q. And I agree; with a 7- or 8-foot-wide bed, if you want plenty of room for herbaceous things, too, I think some vertical things—columnar things or ones that as Ken says are fastigiate or narrow—Kirsten, I think those would be really dramatic. Placed not like soldiers in a row, of course, but more like punctuation and a little unexpected.
Kirsten. And that was the next question….
Q. Uh-oh! [Laughter.]
Kirsten. It sort of segues into this: There’s lots of talk about which plants to use, but another challenge that I have is how to arrange them. I know it should be sort of a loose matrix; an amoeba-like matrix. But I always struggle with the spacing and the grouping.
Q. And I definitely at all cost avoid the soldiers and something that looks mathematically calculated unless it’s a very formal garden or it’s meant to be a hedge or screen at the back of the border. Everybody always says to buy odd numbers of things.
Q. But I something think buy odd numbers plus one, and put the other one farther down the bed and have a cluster at the other end. I kind of like odd groups.
Ken. I was just thinking the same thing; I like 3’s and 5’s. You can group three of these vertical things together in one spot, and then further down the border or closer in you could do one or two, to repeat or echo it.
Q. I hope we’ve been of some help, Kirsten. Ken mentioned some twig dogwoods, and I love ‘Silver and Gold’ [foreground above], with white-variegated leaves in the growing season and gold twigs in the offseason, and also Cornus sericea ‘Sunshine’ [photo top of page[, which has gold leaves in the warm season and incredible red twigs in winter. Those are two other favorites.
will an accidentally cut-back redbud recover?
Q. Let’s do one more little quick question next, Ken. Kathy in Pawling, New York, asked in the comments on the website: “So the redbud I bought on sale about 15 years ago had several of its main branches split so I had to take it down. But in its place are several suckers. Will any of these grow into a new tree? Or will it be more of a shrub?”
Didn’t you have this happen to you, Ken?
Ken. It did. A big branch of a white pine fell on my beautiful young white-flowered redbud. It broke just about 10 inches off the ground, and it’s alive and doing well, but it’s a multi-stemmed small tree—like you might see for a crabapple. What you can do, and maybe I should have done, is choose one, and get it back to be a tree again.
You’d choose perhaps the strongest or the most vertical sucker, and you’d have to cut off the other suckers down to the ground. And you’d probably have to do that for a couple of years, because they’d keep coming up. But then you could encourage it to be a tree again.
If you’d like a multi-stem giant shrub, you can just let it go, and thin any crossed branches, or if gets congested; shape it the way you’d like it to look.
Q. And the only other hesitation is if it was a grafted redbud; she’d have to be on the lookout for that.
Ken. Oh, I knew you were going to say that. [Laughter.] Like my white one, but it broke above the graft.
stink bugs and vining crops
Q. We actually have a caller on the line from North Carolina. Charity, are you there?
Charity. I am.
Q. And your voice sounds very familiar, Miss.
Charity. That’s right. You used to be my boss.
[Charity and I worked together at MarthaStewart.com in New York. Now a mother of four young children and living in North Carolina, she creates a website about kids and food called Foodlets.com.]
Q. It was hilarious that out of the blue comes an Urgent Garden Question from one of my ex-colleagues, who now has relocated to North Carolina. What’s your question?
Charity. My question is about stink bugs.
Charity. Every year they come in and just decimate the whole garden. I’ve only been gardening for three years now, out of all of my years; I’ve always lived in cities. This is my first attempt, and I am trying not to just spray them with all the poisons, but then at the end it’s just a race to harvest the zucchini before the stink bugs eat all the vines. What can I do to stop them?
Q. This question got me going in so many different directions. It was like this journey, thinking about your question. One of the things that I always have to do when I see insect pests in the garden, unless I am 100 percent certain what they are, is to be very careful not to misidentify them, or to identify them just by a common name.
I don’t know if a neighbor might have told you the name of these bugs perhaps, or did you look them up?
Charity. I feel like my husband told me; he’s from Florida.
Q. The thing about “stink bugs,” which is sort of a generic term, is that there are 5,000 species in the world or something.
Ken, Charity. [Laughter.]
Q. So it’s kind of like saying “bird.”
Ken. Or “fly.”
Q. It’s a little more precise than “bird,” but still; there are so many different stink bugs. And then, with stink bugs, making things even more complicated: You just said the vining crops, that they are bothering your squash—and of course a near-lookalike bug that’s kind of a cousin (in the same order or sub-order if not the same family of insects) are called squash bugs. And they also stink. [Above, photographed at Margaret’s; more about squash bugs]
Ken, Charity. [Laughter.]
Q. So now our head is really spinning, right? What also happens is a particular kind of stink bug has become more and more in the news. It’s called the brown marmorated stink bug [left], an Asian pest that was introduced accidentally in Pennsylvania in the 1990s and has since migrated, and I know it’s in your area and many others already. And it’s getting all the headlines. But it’s not so common a pest of the Cucurbits—the squash and pumpkins and cucumbers—but more in other crops, like apples and grapes and tomatoes. [Photo from StopBMSB.org, a university collaborative effort to deal with the pest with extensive reference information.]
So this is where I then wonder: Hmm, is this a stink bug, and if so which stink bug? So without sounding like a crazy person [laughter], I love this site called BugGuide.net. I actually take pictures of my insects; I capture one and put it in a container and take close-ups of the top and bottom of the bug and really try to make sure I am ID’ing it, because to come up with a control method, we have to know exactly who it is and what its life cycle is.
Are they shield-shaped—almost as wide as long—or a little more elongated, like a third or half as wide as long?
Charity. I would say more shield; they look like a little turtle almost.
Q. That’s more like a stink bug; they’re more shield shaped. Do they come in your house?
Q. The brown marmorated stink bug will, which is why it has gotten all the headlines; they love to take cover in residences. If you have such a big infestation I’d expect you to see them in your house in the winter.
Charity. It’s really temporary. It’s almost as if they have a Bat Signal. They come in, they eat all the plants, and then they leave.
Q. So whether they’re squash bugs or stink bugs, here is what I am going to suggest: planting a trap crop, which is something that farmers do a lot to lure them elsewhere. You’ve tried some sprays?
Charity. I’ve tried Neem, and I think it was too late for that.
Q. The best time to spray when using the least-toxic spray, like even an insecticidal soap, would be when you see the eggs, and damage those with a lower-toxicity material, before they have their shells. When they’re adults, the insecticide recommendations get more scary.
The idea to trap or lure them to another plant that you don’t mind if they eat—or to another planting of these desirable plants that you don’t mind if they eat, planted at a slightly different time.
I always plant my squash in two batches, not because I have lost the first crop, but because I know I will have some insect pressure at some point, and they will decide which one they like better but won’t usually take both generations. So at a distance I’ll plant a related crop or the same crop, a couple of weeks apart.
If it were brown marmorated stink bugs, you could have used okra as a trap crop, speaking of Southern vegetables. [Laughter.]
So perhaps don’t put out your squash so early, and instead try to attract the pests to a trap crop. First, we have to identify what they are to pick the right trap crop. Generally with both of these insects, row covers can help. Have you tried those?
Q. When you put out your plants or sow your seeds, put lightweight Reemay or Agribon lightweight fabric with enough room in it for the plants to grow, pinned down with earth staples or weighted down with soil or stones—probably stretched over hoops. The key here though is you don’t want to do it in the same spot you planted squash last year, in case pests are overwintering. You want to rotate the area. [More on using row covers. Also: Hudson Valley Seed sells the fabric by the foot, and also hoops.]
So those are some tactics: To get a good ID; to consider row covers; trap crops selected depending who it is, planted earlier and nearby (but not too near).
Ken. I wanted to quickly say that turning the bug over and photographing the underside was a really good suggestion.
Q. Absolutely; get all the views! Do you have squash bugs or stink bugs, Ken? Or maybe you don’t grow squash.
Ken. Sometimes I grow pumpkin, actually, but I do have stink bugs—and sometimes indoors. But they are not the Asian brown marmorated ones.
Q. Me, neither. The ones I have indoors are actually I believe a squash bug, oddly enough. I’ve been trapping them and looking at them and trying to key them out.
Ken. I have to go to BugGuide.net. Mine look exactly like the Asian marmorated ones, but that’s why I was interested in the underside: one has a chartreuse-y green underside and one has a brown underside. There are a lot of ways to try to tell them apart, and that’s an easy one–unless you get stinked. So turning them over is a little tricky.
Q. Questions, questions: Christina on Facebook asked one, and she is worried about the connection between oaks and ticks. Her question:
“I wonder if you would recommend removing a huge pin oak tree that grows 20 feet from our house? Concerned about roots but also the rodent/tick issue? Should we replace plant another oak (2-acre property) for the animals/nature and if so, how far from the house, please?”
I don’t think that’s too close to the house, do you?
Ken. No, especially since oaks tend to have deeper roots, like tap roots, more than something like a maple that would have roots closer to the surface.
Q. I would never take down an oak because they are such high-value trees for the environment, with sustenance for so many creatures. I treasure the oak trees here, but understand what she’s talking about, the acorn-tick connection, and I have interviewed scientists at Cary Institute in Millbrook, New York, where they have studying that for 25 years or something.
In a mast year, when you get a lot of acorns, you get a lot of food for a lot of animals and birds, including for more [generations of] mice and chipmunks, which are often the vectors for Lyme and other diseases. When the tick bites them [to take a blood meal] they can become infected with disease; the ticks are born without disease. So she’s worried to have more acorns feeding more mice and chipmunks and infecting more ticks, but I think the value of the oak outweighs that.
sourcing garden shrubs and unusual plants
Q. Should we talk now to Susan in Virginia, who has a question and I think is on the line?
A. I am here, but I’m not in Virginia.
Q. How’d I put you in Virginia? [Laughter.]
Susan. It’s my email address.
Susan. I wanted to ask about sourcing information for flowering shrubs. I was hoping to put in a hedge of viburnum and juneberry and spicebush [above, blooming at Margaret’s], but I don’t know where to really get them.
Q. And you’re in upstate New York (not Virginia.) [Laughter.] Ken I want to ask you to talk about some of your favorite sources, but before we do I want to put in a pitch for making friends with your best local woody plant nursery. By that I mean going to whomever is in charge, especially the owner, and saying, “Hey, I’m interested in some different things; do you order thing for customers? Will you let me know what you have access to wholesale?”
Thankfully more than 20 years ago I made friends with a nursery owner near me and I’ve learned so much from him over the years, and I also learned that nurseries are happy to help you get anything if they can find it in the trade. That have trucks coming in to stock their nursery. It won’t work at a big-box store, but at the best nursery near you.
I like to do that as soon as they are answering the phone again in late winter, or even the fall before. I’ve gotten unusual things that way.
Ken. I think that’s a great idea, and the plants that Susan mentioned are not that unusual. And I think any nursery should want to do that because they’re going to make money. There is an incentive for them as well.
And if the plants are native plants, there are a lot of government projects of plantings and restoring areas—so those plants are around.
Q. Ken, what are some of your favorite sources? You know when I have my Open Days in the garden, my friends from Broken Arrow Nursery come and sell plants, and they stock great things and do mail order as well. Obviously the limits of mail order are that things will be smaller. Other places Ken?
Ken. When we started the garden here 20 years ago, we got almost everything through the mail, but there were a lot more sources 20 years ago, when people were collecting plants.
Broken Arrow of course is great. Quackin’ Grass—have you ever used them in Connecticut? They’re another good mail-order place. Rare Find Nursery in New Jersey has good-sized plants and they are mail order. If you have unlimited resources, Forestfarm Nursery in Oregon. Their plants aren’t that expensive, and they do have big ones, but the shipping will kill you.
Q. Forest Farm is amazing; the list is crazy.
Q. But as Ken says: they’re going to ship it across the country, and that will cost you. Which is another reason to make friends with the local nursery. I come in there with crazy lists, Susan, so don’t be shy. Right down to the cultivar; I don’t just say, “I want a Clethra,” but “I want this particular dwarf one with the exceptional flowers.” and they’ll find it. Do you have a favorite nursery in your area?
Susan. There are a few good ones. But I haven’t actually tried asking for the very specific ones I’ve seen in places including your website.
Q. That’s where I’d start, because it will save you the shipping—meaning you can put the money into a larger specimen. If there is something super-new and rare, I buy the small one by mail order.
preventing damping off of seedlings
Q. Ken, I wanted to ask you a question that two readers have asked me recently, about damping off—the fungal condition that can kill seedlings. It can be devastating to lose your whole flat of seedlings; they just kind of collapse. Any advice?
Ken. I do; I used to always have damping off, especially with tomatoes. They come up, they look great, and are about an inch tall and they start to keep over.
Damping off is a name they give to a series of fungal diseases that attack young seedlings. If you’re looking at the stem, it kind of collapses a little bit and turns brown next to the medium surface, and that’s it—that’s the end, especially if you don’t have the true leaf, the first leaf that resembles what the adult leaves will look like on the plant.
About 20 years ago, when I was writing “Making More Plants,” my book on propagation, I tried different methods of doing everything. One thing I did with all my seeds when sowing, was top-dress them with either a thin layer of chicken grit—and Margaret I know you know what that is—or very coarse horticultural sand. [Above, Ken’s photo of chicken grit to show scale.]
Both of those are a little weird to find. Chicken grit, if there is any ag-supply place near you, you can find it, because you cannot have chickens without chicken grit. Usually it’s flaked granite; sometimes in coastal areas it is flaked and chopped-up oyster shell, and you don’t want it. You want it to be stone.
I put a 1-to-3-grain layer on the surface of my sowing medium, with the seeds sown under—or if they are seeds that are tiny or need light to germinate, I sprinkle the seeds after I put that little bit of grit or very coarse sand on the top.
For 20 years—I should knock on wood—I have not had damping off again.
Q. So basically you’re mulching your seedling flats…
Ken. I actually sow in 3-1/2-inch squash plastic pots [photo at top of question].
Q. So you’re sowing in community pots or small pots, and you’re mulching the surface with this chicken grit from the farm-supply store, or coarse sand—is that the other thing you mentioned?
Ken. Coarse horticultural sand is not as easy to find, but it’s very coarse, and a little bit bigger than parakeet gravel, and I think in a serious pinch you could use parakeet gravel. I have used it—they sell it in the supermarket. But sometimes they add things to it, which is not so great.
But what you are doing is making an inert, sterile surface. I also fill the pots with the medium so that I don’t have a reservoir for watering [at the top], because you don’t usually water seedlings from the top anyway, you water them from the bottom. But sometimes people recommend leaving a quarter-inch or half-inch [below the pot rim] as a reservoir for water, and I think that impedes air circulation a little bit. So I just sprinkle the grit on the surface
Q. So damping off: problem solved! [Laughter.]
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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 February 13, 2017 show right here, and also use the buttons below to subscribe to future shows, free.