night-blooming cereus, degrees of shade, growing peas, deer rut damage: q&a with ken druse

YOUR URGENT GARDEN QUESTIONS answered! Longtime friend and expert gardener Ken Druse and I introduced a new feature on my public-radio show and podcast (and transcribed here on the website): a monthly listener question-and-answer episode. In the kickoff episode, we took questions about shade, black walnut, growing peas, deer damage and more.

And extra good news: For those subscribing or listening to the podcast version instead of ion live radio, each month’s Q&A show will be longer than a normal broadcast—like a doubleheader with bonus minutes, so we can get to even more of your questions if you subscribe free on Stitcher or iTunes. Part 2 of the first call-in program—where we talked more about peas, and took questions on gardening under black walnuts, growing strawberries in pots, and badly pruned hydrangeas, is 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, until summer 2016. The Real Dirt podcast archive and much more from Ken is available on the newly re-launched website KenDruse dot com…and is still available on iTunes, too (as is my show).

Read along as you listen to the Jan. 16, 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).

q&a: night-blooming cereus, what makes for shade,

deer damage, and growing peas



Q. Do you realize we’re celebrating our silver anniversary, Ken?

Ken. Un-uh. [Laughter.] What do I get?

Q. You don’t get anything; forget about it. But 25 years we have known each other, and been collaborating on crazy garden stuff. Twenty-five years: I counted.

Ken. We were in prams together.

Q. That’s right. I think we met when I called to interview you in 1992 on the publication of your book, “The Natural Shade Garden.” We done lots of crazy things together: We’ve worked on books together, we’ve appeared on each other’s radio shows, we’ve appeared at events together.

Ken. We traveled the earth together.

Q. We did; you took me to some of the greatest gardens I have ever seen. You let me come with you when you were doing your book called “The Collector’s Garden,” right?

Ken. I remember going from Taco Bell to Taco Bell.

Q. That was us, honey, You know how to show a girl a good time, that’s for sure. [Laughter.] But anyway, you got off cheap with me.

Just for perspective for our listeners: I’ve always gardened in the Northeast, expect for a very short stint in Northern California, in the Bay Area. You’ve gardened on a rooftop in New York City, and where else?

Ken. In a backyard in Brooklyn, and for over 20 years in the northwest corner of New Jersey—which used to be rural. And now…

Q. It’s a little busier.

Ken. I’ll say; it’s different. [More on Ken’s N.J. garden, from his website; photo above of one small part.]

Q. Before we get to our first caller: You’ve lectured a lot, like I have, over the years/decades; you’ve been in front of a lot of audiences. You’ve been asked a lot of questions—you did radio for a long time, and your podcast—you’ve been asked a lot of questions there, too. Do you know what is the Number 1 question you’ve been asked a million times?

Ken. Yes, and you’re going to be surprised I think.

Q. I would think it was tomatoes, or hydrangeas, or roses, but….

Ken. Or like we used to say: “Green side up” or “pointy side up” with bulbs.

Q. [Laughter.] Exactly.

ken’s most common question

Ken. But I think the most-often-asked question for me is, “Why won’t my night-blooming Cereus bloom?”

Q. “Why won’t my night-blooming Cereus [below] bloom?” Really? That’s a popular question? Wow—did you do a show about that or something? Or do you have one?

Ken. I did a show about it, and I got so many questions I did another show about it a few years later. The another one on Epiphyllum—which is the Latin name, Epiphyllum oxypetalum. People grow this not-very-attractive plant for years…

Q. [Laughter.]

Ken. …and they can’t get a bloom on it. Always, if you look at the directions, it says to grow it really dry and lean, and don’t repot it—keep it in the same pot. And then you know it grows and falls over! I’ve found kind of by accident that that’s not really how to make it bloom.

Q. And…?

Ken. I grow it cool and kind of dry in the winter—I don’t even think about it. And then in the spring, just about every other year, I pot it up, just one size. If it’s in a 10-inch pot I’ll go to a 12-inch pot. It likes to be juicy—I say you juice it up. I’ll even feed it with an organic fertilizer, maybe fish emulsion, and put it out in half-day sun for the summer. And I usually have rebloom—last year it bloomed about three times. The first time it had 12 flowers, starting in August.

Q. Wow.

Ken. My instructions to people who ask is don’t necessarily grow it lean, and in poor soil, which is what the directions always say. Juice it up in the spring—it has worked for me for years now.

Q. Night-blooming Cereus how-to from Ken Druse—his most popular question. And I would never guessed—that would have been the last plant I guessed. I have never grown one, but now I know how, so I guess I’ll be ordering one.

Ken. But you don’t know why. [Laughter.]

Q. I don’t know why. [Laughter.]

Before we take our first caller, I want to say how people can get in touch with this new monthly feature and ask a question: People can ask questions in a number of different ways.  

They can always find me on Facebook and ask a question there, and a number of people did that this week in anticipation; we’ll have some of those in a minute.

Also: On A Way to Garden dot com, there is a little link at the bottom of any page that says “contact” that goes to a contact form.  We’ll pick the best ones each month—and when I say best…

Ken. [Laughter.]

Q. …I mean representative of what people are asking about, that’s timely, and the most people are asking about. If your question is selected, we’ll email you and set up a taping time. That’s how it works, following the model of a lot of the NPR types of shows, where it’s kind of “appointment calling,” since we’re all in different time zones, and when someone’s hearing the show live wouldn’t be when we were recording it.

So let’s get our first caller on the line. Dare I?

decoding the degrees of shade

Welcome Marsha from Tennessee—congratulations, you’re our first victim! [Laughter.] How are you, and what’s going on down there?

Marsha: [Laughter.] I will tell you I just got back from some volunteer time at a charity garden, where a group of six women were turning compost piles.

Q. Good, well then you’ve had your exercise for today. What’s your question?

Marsha: My question has to do with shade. As a veggie gardener, we focus on getting at least six hours of sunlight or more, in order to successfully grow veggies.  But lots of people grow other things, and this whole definition is what constitutes shade—if it’s less than six hours [of sun], does that mean it’s shade? And then of course the morning sun is not as intense as afternoon sun—does that make a difference?

My question really was what are the different gradations of shade, because I hear people talk about “light shade” and “dense shade,” and what does that really mean?

Q. Well we have Mr. Shade King over here on the line—we have Ken to ask. And again, I think it’s important when answering this question to note that you are calling from Tennessee, and shade is a little different in different regions, as I am sure Ken will mention.

There is a little bit of noise on your end, Marsha, so perhaps our engineer will mute your line while you listen to the answer. So Ken, what do you think? What constitutes shade?

Ken. Everyone has a different description of what shade is, and everyone is optimistic about what they can grow in the shade.

If you look at the tags on the plants, it has a full open circle for full sun—and then a circle that’s half black and half open, and that’s the partial shade or medium shade or shade. And then there is the full dark circle on the back of the tag that’s shade.

You read the catalogs and if you look up “shade plants” or “shade perennials,” I can’t believe what they put there. I can’t grow those things in shade.

The question is about the degrees of shade or the amounts of shade, and what you call it. It’s hard to say because they’re calling that half circle partial shade, and they’re recommending plants I can’t grow in partial shade.

I tried in my last book [“The New Shade Garden”] to define these different kinds of shade, and to describe them. So I say light shade is around six hours of direct sunlight at the height of summer. If you’ve got 16 hours of sun in your garden and it [the plant label] says half-shade—well then that’s eight hours of sun. And I don’t think eight hours of sun is shade…

Q. [Laughter.]

Ken. …because our caller knows that she can grow a tomato in eight hours of sun, especially in Tennessee—because heat kind of ripens foliage. And if you live in the far North, in Maine or Canada, your hours of daylight in summer are longer, so you have a different kind of shade there, too.  So light shade I’d say is around six hours of direct sunlight—and some people would call that sun.

Filtered light is four to six hours of sun, and that might be a place under a few high-limbed trees or below and open structure—or on the east side of the house.

Medium shade is two to four hours of direct sunlight, or light all day beneath a translucent cover or light that passes through feathery foliage of a tree like a honey locust tree. You might think of that as the dappled shade, where the light is constantly fluttering.

Now full deep or dense shade—that’s not really the dark, because nothing can grow in the dark, except maybe mushrooms. We’re talking about two hours of direct sunlight or very bright light. It could be a plant that’s right up against the north side of a building.

Something that hardly anybody talks about is something I call woodland shade. If you have a place that’s in full sun under deciduous trees, trees that lose their leaves and are naked in the winter—you’ve got full sun. Then the leaves come out in mid-May for me, and then you have shade.

In that situation, in woodland shade, there are a lot of the spring ephemerals that can be grown like trillium [above, T. erectum] and Virginia bluebells and trout lily. Those plants bloom early and set seed and very often they go dormant. They might lose their leaves and then they end up in dense shade.

Q. Yes, I think of that as these opportunists—they know that they will get shade later, so they make hay while the sun shines. [Laughter.] You know what I mean? They come out early, and grow very fast and as you say go through their whole reproductive cycle, and then may go dormant, depending on the heat and drought and whatever.

The other kind of shade that’s trickiest is under evergreens, I think. The same amount of light under some conifers seems different from the same amount of light under some deciduous trees—if that makes any sense. Because it’s always darker under there—all year—and it’s drier, too, under the conifers (and certain other kind of trees, too). But do you know what I mean?

Ken. Yes, and dry shade—that’s the bane. And people are always asking me: “Can I dig up the roots of my tree to plant in there?” And the answer is, “No.” [Laughter.] You can plug in—and plug is a good word—you can plug in some groundcovers, if you buy the little baby ones, or even plant seeds among the roots of a tree. You can’t do it under a beech because the roots are so shallow, and you can’t in some evergreens.

I always tell people that if they have dry shade that is really hopeless, grow containers. Put containers up on a few bricks carefully—not right on the roots if you see the roots, but in between the roots. You can try things, and it’s making me think that you can test the amount of shade with a plant.

You and I both grow that big-root geranium.

Q. Geranium macrorrhizum [above].

Ken. And if that plant flowers, you’re sort of in the filtered light zone—you’re in the four to six hours of sun [or more]. If it doesn’t flower, you have less than that—and if it croaks, you have even less that that. [Laughter.]

Sometimes you are surprised. I grow a lot of Brunnera—sometimes it’s called bugloss, though I have never heard anybody call it that, or perennial forget-me-nots [below]—and they grow and bloom in what I would call shade, even full shade. Two hours of sun.

Q. Thank you, Marsha, for such a great question—did that seem to help a little bit?

Marsha: It does. I always wondered about the plant tags.

Q. [Laughter.] We did, too. How can they be right for all places?

Marsha: And there are really only three categories: full sun, partial shade and full shade.

Q And it doesn’t really deal with what Ken was talking about—like if it’s a tree with feathery foliage versus something dense like a stand of conifers.

Ken. And I know you’re a vegetable gardener, which is tough in shade, but you can grow some leafy lettuces and maybe arugula—things like that.

Q. Rhubarb [below, emerging], and parsley.


Ken. Rhubarb: That’s another tip. If you see a plant with big leaves, those big leaves are there to gather as much light as possible, so it’s kind of a tip that the plant might be a little more shade tolerant.

Q. Marsha, thank you so much for being our first caller.

deer-rut damage to bark

Q. You know Ken, I wanted to just tell you a question that we had on Facebook about deer.

Matthew said: “While I do have a deer fence around half of my property, the other half is open and often visited by marauders. This fall, a few small trees were rutted…” during the deer rut season, by the bucks, “…specifically a paper bark maple, an ornamental peach, and a Korean fir.”

Ken. Aw.

Q. So what can he do, he wanted to know? I answered him because I felt so bad. When you have bark damage, it depends of course on how deep and large the scars are if the tree can cope—and also on the age of the trees. Young trees usually do worse, and unfortunately his are young trees.

The worst damage of all—and I don’t know if you have noticed this, Ken—but it’s typically lethal if the trees are girdled—that is, if the bark damage extends all the way around the trunk.

Ken. Yes.

Q. I have seen trees with a big vertical scar that have healed over…

Ken. In 20 years.

Q. When I say healed over I guess I meant the tree didn’t die, but not that it got new beautiful bark, sorry. So what I suggested to Matthew was to clean up any peeling, stray bits of bark a little bit, but do not paint any “wound dressing” or other substance on the scar.

Ken. Deer love to rut young trees. I haven’t done this myself, but I have seen it done. You can get those cedar stakes, like a 2-inch caliper cedar stake with the bark on it, and you pound it into the ground near the tree you love, they will often go to that stake.

Q. So a decoy, OK. [More on discouraging deer.]

how to grow peas

Let’s say hello to Susan from Virginia.

Caller: This is Ruth.

Q. [Laughter.] I’m a bad person; I have the wrong name. I’m a nincompoop.

Ruth: But I am from Virginia.

Ken. Did you change your name?

Q. I’m so sorry [laughter]. Where in Virginia are you?

Ruth: I’m in Amherst County, close to Lynchburg. Kind of on the eastern side, pretty close to Sweet Briar College.

Peas ready to harvest.Q. And you have an urgent gardening question for us, do you?

Ruth. I do. I was wondering about growing snow peas. I’ve been trying to grow them for a couple of years. First year I had great success, then I tried them last year and kind of just threw the peas in the ground again, and they didn’t come up. I tried another approach a little later—because last year was really cold.  I thought maybe it’s delayed a little bit, so I put some in some paper towels in the refrigerator, and they did start to sprout, so I put those in the ground—but even those didn’t come up.

So I had some questions: Can you start them indoors? I have read that you can’t but wanted to know.

Q. So when you say “snow peas,” you mean any edible-podded pea—not specifically the kind with flat peas that are in a Chinese stir-fry dish?

Ruth: Yes.

Q. OK, good. I have lots to say about that.  Eliot Coleman, who is a Northern gardener in Maine and a famous vegetable gardener who has written great books—he used to start his indoors, but now he starts them in his coldframe (or the most recent time I read about it, he did so). He started them in the back of his coldframe, and by the time they were up to the glass, he opened the coldframe for good. So in other words, he started them under protection outside, to get like an extra headstart.

So they can be started indoors and transplanted [as he did previously], but generally if you can direct-sow you are adding one less stress to the young plant.

With peas, timing is everything, and they are very tolerant of cold—more so in a spring sowing than a fall crop, which is a bit more susceptible to frost. But there is also the whole subject of inoculants. Have you ever used them?

Ruth: No I haven’t.

Q. Ken do you use them—or do you grow peas?

A. Years ago I grew ‘Sugar Snap’ peas on the roof in Soho in New York City. I sowed them on St. Patrick’s Day, and I didn’t use inoculants—and I was even using a soilless mix. They did very well, and the hard part for me was keeping up with the harvest.

Q. And that’s the worst conditions!

Ruth: I wish that was my problem. [Laughter.]

Q. So if you’re having trouble, they’re big seeds and one thing they are not going to want is to be in wet soil—especially cold, wet soil.

Ruth: OK.

Q. So we want to say that the soil is at the “chocolate cake stage,” as we used to say when we were learning to garden, right Ken? Which is if you were to take a piece of chocolate cake—delicious chocolate cake…

Ken. [Laughter.]

Q. …and you were to squeeze it in your hand gently, it would hold together but water would not come dripping out between your fingers. It’s moist, not wet. So we want to wait until the soil is at the chocolate cake stage before we sow our pea seeds in the ground.

Ruth: You would think raised beds would work.

Q. Correct. And I grow in raised beds, which is one of my advantages in this matter—mine drain out sooner.

The other thing is: I don’t think the inoculant can hurt. It can be a waste of money if it doesn’t help, and they have to be matched to the right crop—one labeled for use on peas.

legume inoculant for peas and beansBut if you have not had success growing peas or any legume in a particular situation, I was reading an interesting bulletin on Colorado State University Extension about use of inoculants.  And if you haven’t grown legumes in the area, or had success, so you don’t have a track record, it is recommended that you use an inoculant. You can take your peas seeds and put them in a little Baggie with the inoculant and shake it up, or I put it in a bowl and spoon the seeds out. Or with a teaspoon you can actually sprinkle it in the ground, if you make a furrow first.

Chocolate cake stage—not cold, wet soil—and I’d use the inoculant. And you’re on to something when you say raised beds; you’re trying to simulate that kind of decent drainage.

Does that seem to help? One more thing about peas: Try different varieties. I have some that are my standards that really work for me. Find ones that are suited to your area, perhaps from a catalog that specializes in your area may also help you [examples: Southern Exposure Seed Exchange or Sow True Seed.] Thank you so much for calling.

[Version of the show for radio broadcast ends.]

Q. Ken and I are going to continue after a little break. [In Part 2—the bonus minutes—we talk more about the best peas, about gardening around black walnut trees, and growing strawberries in containers.]

how to ask a question

WANT TO ASK a question for a later show? You can do so in two ways: Find me on Facebook.com/awaytogarden and ask a question there, which a number of people did in anticipation of the first Q&A show. Or use the little link at the bottom of any page on this website that says “contact,” which goes to a little contact form. Very easy. If your question is selected, we’ll email you to set up a taping time on the show.

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 Jan. 16, 2017 show right here. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here).


(Photos of night-blooming Cereus and Brunnera courtesy of Ken Druse. Purchases from Amazon affiliate links yield a small commission.)

  1. Bill PlummerI says:

    I have all grades of shade on my wooded lot from dense shade (in summer) under the tree canopy to afternoon sun in a west-facing site. Other sites receive full sun for a few hours or dappled shade throughout the day. An east-facing stone wall receives enough light to grow rock garden plants. Other sites are shaded, but are open to the sky and qualify as part sun/part shade. Years ago I used my camera to quantify degrees of light throughout the day at dozens of sites.

    Incidentally I do not consider trilliums as ephemeral. Unlike the true ephemerals like Virginia bluebells, trout lily and Dutchman’s britches, trilliums (and bloodroot) retain their leaves into late summer and fall.

  2. Lauren B. says:

    I have a lot of bleeding hearts, brunnera, trillium dutchmans breeches, trycyrtis, hellebore, some annoying kind of fern, bishops mitre, etc, on a hill under a big old kwaanzan cherry tree. They get just about zero sun but do well. In my backyard none of these things or anything else does well as the soil is unimproved and there are nearby pin oak, red maple, and wild cherry that make it dry shade. Dandelions and wild garlic, pink flowered knotweed, and garlic mustard have a party there.
    I took a quick peek at Mr. DRuse’s website and it is indeed eye candy. Plus I am sure there is all sorts of stuff for me to learn there! Just right now I am knitting socks. As usual I enjoy your presentations. Oops, look out for those allelopaths!

  3. Gayle Chatfield says:

    Night blooming cereus:
    I have a huge Epiphyllum oxypetalum that began blooming vigorously when I moved it near huge east windows, over 20′ wide by 11′ tall. Second year in this spot it bloomed 4 times with 10+ blooms each time. It needed more light. I keep this inside in summer but friends move theirs outside to bright, indirect light areas and they bloom well then. I live as far north in Wisconsin as it gets, near Lake Superior. It’s fragrance is as intoxicating as it’s appearance.

    Margaret, yours is the ONLY blog I make time for, thank you for it. It’s so worth it!
    (Used the mousetrap recommendation, they are super!)

    1. Eva Munday says:

      My neighbor collected all of kinds of plants and kept a few I didn’t recognize on her picnic table outside in semi shade. One day she said “meet me outside at 10:30 tonight at the picnic table, I have a surprise for you!” I met her outside, and to my surprise she was in her pj’s! She shone a flashlight on one of the plants on the picnic table on a bloom that yesterday was insignificant and now was slowly opening. I couldn’t believe my eyes how beautiful it was and then finally the scent-so heavenly-I had never smelled anything that good! We finally parted and went to bed.
      Of course, the first thing I did was check on the plant in the morning before work. The beautiful bloom was gone, just a pile of mushy flower parts. Well worth growing!

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