HOW’S THAT SPRING CLEANUP and planting and weeding and mulching and edging and and and and and…how’s it all going, gardeners? Ken Druse and suspect that with every day outside you probably uncover not just a bed or two with your rake, but also some puzzles you need help solving. Like what plants could add color to shady spots, or strategies for tackling earwigs, or which way the beds should run in a vegetable garden (north-south? east-west?), or what the protocol is for growing shrubs and trees longterm in pots. 

Your Urgent Garden Questions have been arriving in blog comments, on Facebook, and in emails, and we’ve rounded up the most representative ones to tackle today, in the monthly Q&A episode of the program. (All past editions of our Q&As together are at this link.)

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, all available on KenDruse dot com (and on iTunes, too).

Let’s dig right in:

Read along as you listen to the April 24, 2107 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here).

Oh, and that creature up top? Yup, that’s the common or European earwig (photo by James Lindsey at Ecology of Commanster, CC BY-SA 3.0, from Wikimedia).

april q&a with ken druse: earwigs, shrubs in pots, color in the shade

adding color in the shade garden

Q. Here’s a fast one for you, Mr. “The New Shade Garden” (your great and most recent book). It’s from Facebook, from Diane in Long Island Zone 7. She says:

“I’m looking for some colorful flower/plant ideas (that aren’t Hosta) that can thrive in the shade. We have so much green there, I’d love to have a pop of color.”

Seems like there are lots of possibilities, right?

Ken. And there are lots of hostas, too, that have beautiful flowers, but it sounds like she has a hosta takeover.

Q. [Laughter.] Yes.

Ken. There are so many shrubs, but I am getting the feeling she wants herbaceous perennials—things like the hostas. I’m in love with Acanthus hungaricus, though in Zone 7 she can grow most any Acanthus, the bear’s breeches. A. hungaricus has a tall flower spike around 18 inches tall, and it blooms for well over a month. [A. hungaricus photo by Ken Druse.]

Aruncus—goatsbeard—I know that’s a favorite of yours, Margaret.

Q. Yes.

Ken. That goes to around 4 feet with feathery white flowers late in the spring, and the bees love it.

Q. I like the mini one, too, Aruncus aethusifolius.

Ken. Yes, but she wants color. She wants to see it from 5 feet away. [Laughter.]

Asters—there are plenty of those in the late season, woodland asters. Astilbes are a favorite for shade and there are tons of those.

Early on there is bleeding heart, which got their name changed from Dicentra to Lamprocapnos.

Q. And I like the one with the yellow foliage, ‘Gold Heart,’ so you get double color, not just the bloom time.

Ken. That’s true, but it’s a little shocking.

Q. Well, I’m a shocking person. I’m psychedelic, baby.

Ken. I don’t know if you grow Brunnera, the perennial forget-me-not. The catalogs say it’s Siberian bugloss, but I’ve never heard anyone say that. I always say Brunnera.  For me in the driest shade and a lot of shade, it blooms for about a month.

Q. And it can have very handsome leaves as well—variegated, very startling that light up the shade.

Ken. Foxgloves, if she has enough sun for that. You and I both love that Geranium macrorrhizum [above], and it has fragrant leaves, though if you crush those you’re going to smell like that for about 20 hours.

Q. [Laughter.]

Ken. My hellebores are still blooming.

Q. Mine, too; they just started about two weeks ago [early April] and I imagine I’ll get another week and a half from them.

Ken. Just started?

Q. Yes, but remember I had snow like two weeks or so ago—and when I say two weeks ago I mean at the beginning or April and the first week in April.

Ken. The snow we had in March flattened a lot of the hellebores, but they’re going gangbusters still except for the crushed ones.

Primroses. Kirengeshoma—you know your neighbor has that wonderful one.

Q. For late bloom.

Ken. Yes. Did I say species peonies?

Q. No, but I was just looking and mine are just coming up [above, the purple-emerging foliage and stems of Paeonia mlokosewitschii; opening flower below].

Ken. Mine are just coming up, too, and they bloom for about an hour and a half in May.

Q. [Laughter.]

Ken. And then they get those beautiful fruits, and seedpods. They’re black, and red.

Virginia bluebells [Mertensia virginica, below], and they self-sow politely. Yellow wood poppy, a very easy plant with beautiful fruits too, and if you deadhead it I have found, it will just keep blooming.

Q. Now do you mean celandine poppy when you say that, Stylophorum?

Ken. Well, there is the lesser celandine, which is the weed, but wood poppy is Stylophorum…

Q. …diphyllum, OK, yes; I have it. [Don’t know which one you have? Clear up “celandine confusion” in this story.]

Ken. And it’s a little bit bigger [above, S. diphyllum]. And I’d have to say, among the best: Phlox divaricata, with those purpley-blue flowers and there are a lot of varieties and they are fragrant, wonderfully fragrant.

Q. That’s a pretty darn good list. We can tell Diane in Long Island that she is set with lots of color for shade.

Ken. And tell her she is lucky to be in Zone 7.

Q. Yes. I also use Hakonechloa, the Japanese forest grass, and some have yellow in the foliage…

A. We didn’t even get into that—but she’s sick of foliage, didn’t you hear that? [Laughter.]

Q. …or into the heucheras.

• [Get Ken’s list of recommended plants for a shade garden.]
  

growing shrubs in pots

Q. I think we have another Facebook user, Erin, on the line. Hello Erin.

Erin. Hello.

Q. Oh, yippee; we did it. I always worry about Mercury retrograde or something, you know? [Laughter.] Where are you calling from?

Erin. I am calling from southeastern Wisconsin.

Q. What Zone do you think you are in?

Erin. We’re Zone 5B, right along Lake Michigan, so there is a little finger of 5B that kind of extends up.

Q. I’m in 5B too, but in New York State, obviously. What’s your question today?

Erin. About three years ago, I planted a boxwood in a large container, and I also did an own-root rose in a large container. I planted both of those about three years ago, and they’ve both been doing great. I overwinter them in my unheated garage, but I’m wondering if it’s time that I should be thinking about repotting those, or pulling them out and replacing the potting mix—what I should be doing for ongoing care.

Q. So giving longevity to containerized shrubs. Ken, I have my own crazy method, but you probably do it more correctly. Want to start us on this?

Ken. How are those plants doing?

Erin. They both doing very well.

Ken. OK then, you’re done! [Laughter.]

Q. It’s funny that you say that, Ken, because my feeling is that I may not get 30 years out of my potted shrubbery and small trees—like I have a lot of Japanese maples in pots. I do the same thing that you do, Erin: I wheel them into the garage on a handcart in the winter, and wheel them back out. [Above, still-dormant pots wait outside the barn at Margaret’s to be wheeled into their seasonal spots in the garden.]

You know what? I don’t do anything special, really. I figure if I get seven or 10 years, even if it was a $60 plant, that’s a lot cheaper for seven or 10 years of buying annuals—tropicals—to fill those pots, right? So I don’t try to get 25 years or 50 years that I might if it were something growing in the ground in the garden.

But there are some things we can do to improve; to do better, right Ken?

Ken. I’m thinking that if you look at the medium—the surface if the medium in those containers—if it seems to have settled or shrunk down, if it’s lower than it was three years ago, you might want to do a little bit of renovation.

I would say with the rose you could just topdress it with your potting mix, even about 2 inches, especially because it’s own-root. You won’t have problems with the graft rooting, and below the graft the stock plant coming up. So I would topdress that.

But boxwood you can’t do that to. They like to be high; they don’t like to have their crowns covered. So with the boxwood, if you can get it out of the container and maybe keep all the medium or soil together, and then put 2 or 3 inches of medium in the bottom of that container, and then slip the boxwood back in.

I’m sure doing it is going to loosen it, so you won’t have to loosen it too much, but if you need more medium you can push it down along the outside of the rootball of the boxwood. So with the boxwood—is there a word for underdress? [Laughter.]

Q. As opposed to topdress? Last year I was feeling like a guilty parent. I just told you my “method,” which is not very methodical, which is hey, I’m going to get seven or 10 years out of these guys without doing a lot. My Japanese maples are in very, very big pots.

Basically, Erin, what I have done is that I started with a pot that was a little bigger than the nursery pot they came in, and then a couple of years later I moved them to a slightly bigger pot, and now they are in my biggest pots—which are thigh-high and very, very wide, a couple of feet across. I can’t move them except on a cart.

So I’ve moved them up, kind of doing what Ken’s saying each time. I was feeling guilty, though, and last fall I had a very strong friend who was visiting, and I asked him if he would help me do this wrestling job.

We put a tarp out on the driveway, on a flat area. We put the biggest of them on their sides, and between the two of us with some banging on the pots (they’re not breakable pots) and jostling and putting a long, thin tool like a soil knife inside the rim, we were able to slide them out–I make it sound easy—on the tarp. Then we got them back in, and turn them back upright. It was a two man, or two-person, job, and did take some doing.

The other thing the experts tell me I am supposed to do while I had them out is root-prune them. Does that ring a bell at all, Erin? Have you ever done that?

Erin. I’m familiar with the process, but I don’t believe I have ever done it.

Q. I’m always like, “How much roots do you cut off?” Say with bonsai as the most extreme example, you’re pruning both the top and the bottom, telling the plant in both directions to stay small, to be accommodated in the small container, with a small root mass.

What a lot of friends tell me the so-called right way is that every second or third year, you slide them out, you root-prune a little bit, you freshen up the medium as Ken was saying, and slip them back into the container.

Ken. Into the same container.

Q. Right, if you don’t want to keep moving them up. Mine are in the biggest container I have; I can’t get any bigger.

Ken. You could probably get a cow trough, or a horse trough.

Q. Oh, right, and I’ll be rolling that into the barn. [Laughter.] I always say my obit in the paper someday—because I live on a very hilly site—will be “RIP: Margaret Roach, was killed yesterday when a Japanese maple ran her over, when she was on the downhill side of the ball cart.”

Ken. [Laughter.] We always say trees have wheels.

Q. Do you feed these guys at all, Erin?

Erin. I do; I feel them actually more frequently than I feed anything else in my yard. I always figure being in a container they need a little bit more. For the rose I use an organic rose fertilizer, and for the boxwood an organic general-purpose fertilizer. I sort of try to water them with fish emulsion or compost tea sometimes.

Q. You’re a good parent.

Ken. Yes indeed.

Q. A very nice lady. [Laughter.] I think you’re on the right track, and I think this is something people should do more of: growing woody plants in containers as sort of a more durable, long-lasting “annuals” for moving around the garden and dressing up areas, making punctuation or making arrangements. I love all my woody things that are tucked in the barn.

Does that seem to help to affirm you are on the right track?

Erin. It does, absolutely, and it’s nice to know with that boxwood that I’ll just pick that up a little bit, because it is sort of shrinking in the pot a little bit.

Ken. Excellent, exactly.

Q. And good drainage; we have to make sure there are enough holes in the bottoms of these big pots, so we don’t end up with a swamp. That’s the other thing—I feel like some of the big pots don’t come with enough holes for the soil volume. In preparing the biggest pots, I’ve made more holes with a drill bit. Have you done that, Ken?

Ken. With a clay pot that’s not the easiest thing, but with a plastic pot I always do that, and that’s easy, and just takes a few minutes.

Q. We don’t want a swamp in there, which would make them decline as well. All right. It’s nice to speak to you all the way from Wisconsin.

what to do about earwigs

Q. Ken, believe it or not, not just one but two readers have recently asked about earwigs.

Ken. Eeewwww.

Q. Sara on Facebook said: “I have a large no-till veggie and flower cutting garden. It is virtually weed free by using masses of mulch.” Unfortunately, she said, she has started seeing huge populations of earwigs the past few years living in the mulch and feasting on various fruits, flowers etc. They nipped off zinnia seedlings and other things, and were detrimental on her fruit trees.

She was wondering if she could put out out the slug remedy or beer saucers or those types of things or something sticky? It’s a big garden, so it can’t be to chase down ever earwig by hand.

Have you had this problem?

Ken. Not on this scale. I had earwigs in a very large planter at the Brooklyn garden, when I still had the Brooklyn garden, in the front yard. It was like 5 foot by 5 foot—a big container. They would crawl into the buds of the rhododendron it was planted it; they were so gross.

What I did was put a small board down on the surface of the soil overnight. In the morning I would go out and there they would be, and though I’m sure I blacked out, but I think I just squished them then. But we’re talking seven to 10—it sounds like she has the invading army.

Q. Seven to 10 thousand.

Ken.  Eeewwww. They’re so creepy, and why do they call them earwigs (but don’t tell me).

Q. I don’t want to know, either. It’s good that your instinct was to put down the board and do that, because they are active mostly at night (like slugs—another thing you might put down the board for, to trap them). They apparently seek out dark, cool, moist places. Like mulch.

Ken. Like all her mulch.

Q. There you go. On every reference site where I looked up earwigs, trapping is always recommended. I have never had a bad problem, just a couple here and there, like what you are saying. But every reference site really talked about trapping as not just the least-toxic method but also the most effective method of control of earwigs, as it is for slugs. (With slugs you can bait for them, as we talked about on a previous program.)

One of my favorite sites for reference, even though I don’t live in California, is the University of California Integrated Pest Management Program. They have an incredible encyclopedia, pest by pest, and they tell you the life history and biology of each pest—what it eats, how it lives, where it lives, what it likes and doesn’t like—and the least-toxic methods in descending order from safest to chemicals. [Earwigs on the California website.]

They kind of teach you about each pest, so you know what you are up against, and here are a couple of kooky things I learned about earwigs:

Those pincers are used for defense, the forceps, but you can tell a male from a female—in case you want to sex your earwigs. [Illustration of sexes above, from BugBoy52.40 on Wikipedia; own work, CC BY-SA 3.0.]

Ken. More than anything.

Q. I knew you did. That the males’ forceps are somewhat curved but straighter in the females. That earwigs may have some benefits: some of them eat aphids (besides your seedlings). And they recommend trapping—the board thing that you said, or: “a low-sided can, such as a cat food or tuna fish can, with ½-inch of oil in the bottom, makes an excellent trap.” Apparently fish oil such as tuna-fish oil is very attractive, or vegetable oil “with a drop of bacon grease” for you non-vegetarians. [Laughter.]  The cans should be sunk into the ground so the top is at soil level.

Or rolled-up newspaper, corrugated cardboard—the boards as you said. People even use a short piece of hose that they cut out of an old garden hose; apparently they’ll crawl into that. The key is to put them out for nighttime and check your traps first thing in the morning.

And then of course garden sanitation, because they love decaying and floppy stuff.

veg-garden rows: north-south or east-west?

Q. I have a quick brain teaser for you.

Ken. Uh-oh.

Q. From Bruce on Facebook, a vegetable-garden question: “Rows north to south or east to west?”

Ken. Eh…eh…eh. [Laughter.] Can I get a lifeline? I would say north to south, and I think you put the tallest things further north, and the shortest things closer south, so they don’t shade the others.

Q. I teased you and said it was a brain teaser, but I had to look it up. Most folks agree that planting north-south is at least marginally better for the reason that you say, which is that you don’t want to shade things by running in the other direction.

But there are a couple of exceptions, and I am on one of them. I am on a slope, so I have to do mine east to west, because the way my land slopes, north to south, my rows would be running downhill. [Laughter.] [Above, Margaret’s raised beds, on a slope that heads downhill toward the north, run east-west.]

Ken. [Laughter.]

Q. And sometimes if you have an extremely windy site, you may also choose a different arrangement, because the wind strength might be damaging.

Ken. Right, not perpendicular.

animal-resistant compost heap update

Q.  Our time’s running out, and we’re not going to do our usual bonus minutes—but I did want to say we got our first serious thank-you card, Ken, from one of our earlier shows. It was from Kerry, whose compost tumbler had died, and she needing to make an animal-proof big compost pile for her farm/garden.

We coached her [in this previous segment] and she sent us some photos of the success. She said:

“Thanks again for your help with my compost and critters question. I’ve attached pictures of my deceased ComposTumbler and my new 40-foot pile. What a difference! Bonus: I weaved clippings from my grapevines into the fence as a screen between our property and our next door neighbors. Your pocket method for kitchen scraps works great; we have no evidence that any of our neighbors, wild or otherwise, have messed with the pile.”

• [Read or listen to the previous episode with Kerry.]

getting ready for spring events

Q. One of the reasons we won’t do overtime today is that if I don’t go back to the garden my May 6 event will be a total disaster. Guess who’s coming to give two talks that day?

Ken. I’ve heard a rumor.

Q. Joseph Tychonievich, who you introduced me to.

Ken. Amazing.

Q. He’s going to give a rock garden talk and a pollinator talk in the afternoon. Now you’ve known him for a number of years, yes?

Ken. I met him when he might have been 13 years old, and when I say “met,” I didn’t really meet him. I think it was during the dial-up days…

Q. [Laughter.]

Ken. I met him online, and I finally brought him to the New York Botanical Garden for our Hortie-Hoopla—a picnic that we have for interns working in the New York City area. He spoke for us, and that was the first time I met him, 15 years after I first met him online.

Q. I think he’s super-talented, just as you said from the very beginning when you shouted him out in “Organic Gardening” magazine as one of the young influencers in horticulture. I so glad to have him come visit—and why don’t you come visit, too?

Ken. Maybe because I’m getting ready for my May 18 tour…[laughter].

• Get all the details about Margaret’s May 6 events (talks, tours, plant sale…) at this link

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 April 24, 2017 show right here. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here).