GRANDMA raised them, her darling hens and chicks–and no, I’m not referring to the egg-producing flock of adorable Bantam poultry in my Grandmother’s backyard, but to her Sempervivum, succulent plants that hugged the ground with their sculptural rosettes, at least till flowering time–when up shot tall stems with dusty pink blooms, if my memory serves.

Years later, when visiting English gardens, I’d smile to see what are referred to as “houseleeks” happily growing on shed roofs, out of stone walls, and in other unfussy spots.

These days at nurseries and in plant catalogs, Grandma’s version, the Sempervivum, are just the start–joined by what my friend Katherine Tracey of Avant Gardens Nursery calls “the other hens and chicks.”

I got inspiration on the creative use of succulents from Kathy on my public-radio show and podcast. Read along as you listen to the April 18, 2016 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).

my succulent q&a with katherine tracey

Q. I want to ask how you became a succulent collector—and even saying “collector” is sort of an understatement considering how many you have amassed over the years. But first: Dare I tell you about the first perennial garden I ever made like 30-something years ago included Sempervivum? It was really embarrassing. [Laughter.]

A. Tell me more.

Q. Well, you’re a famous garden designer…so close your eyes and visualize this incredible idea: I was a beginning gardener; I knew nothing. I made a little bed, and went to the local nursery. Then some perennials were sold in almost like 6-packs, like tomatoes are. I bought an equal number of hens and chicks and Kniphofia—the red hot poker plant…

A. Ooh!

Q. …and then like a mathematician I came home and gridded them out, one hen and chick and one Kniphofia and one hen and chick and one Kniphofia…

A. [Laughter.]

Q. Now she’s laughing at me. And I did the opposite in the next row.

A. Sometimes that geometry is really fun.

Q. It was awful; hideous. I didn’t even know what conditions the plants wanted. But it was my first adventure with gardening, and it involved hens and chicks. How did you get started with succulents?

A. I was always seeking out plants that have lower maintenance criteria, and don’t need a lot of water. Years ago there were a few sedums available to most gardeners—the upright forms, the Sedum telephium, and then the creepers, commonly called stonecrop. Hens and chicks, Sempervivum, were generally just known cultivars and they were often sold as you say in little six-packs.

I also around the same time began to follow the Rock Garden Society, and began collecting little alpine gems. We don’t have a regular rock garden—we have a little rock-garden area—but for the most part we were growing the alpines and rock-garden type plants in troughs.

Every winter I would lose some precious little gem that I had bought, but the little sedums and Sempervivum wintered over just beautifully. So it just confirmed that they were easy to grow, and even easy to winter over outdoors and in containers.

Q. So they won a place because they were true to you right from the start. [Laughter.]

A. They came back. [Laughter.]

Q. And in the beginning, that’s what we like, right? And then of course the world has opened up. You said there used to be the tall sedums like what most commonly is like ‘Autumn Joy’—which was like “new” and cutting edge practically a couple of decades ago, but now it’s like: wow, the world of succulents.

A. There are many new hardy forms of sedum, and I’ve actually found that the darker-leaved hardy sedum are a little trickier in our climate, with our summer humidity. For some reason if they’re not in really sharp-draining soils they will begin to sort of collapse in August. Sedum ‘Autumn Joy’ rarely does that; it’s so foolproof. But some of the dark hybrids like ‘Purple Emperor’ that we had—they’ve come and gone. But now I’m sidetracking into sedum.

Q. Because you’re obsessed with succulents. That’s why we called you today.  With the “hens and chicks,” as I said in the introduction, you have not just the more common ones but also the “other ones,” too.

So the word of the day when we’re talking hens and chicks, whatever genus they’re in, is that they’re “monocarpic.” Tell us what it means.

A. That means that when they erupt into blossom, that rosette will die after the flowers fade. Usually there are many, many offsets at the base ready to take over at the base, where that main rosette begins to die off.

Q. The chicks! [Laughter.]

A. The little chicks are all waiting. We often just lift a few chicks here and there to move them around the garden, so you usually never lose the plant. I’m trying to think of an occasion when I only had one rosette that erupted and nothing remained.

Q. In a container sometimes, when I think the plants are more stressed—like I’ve had them in strawberry jars. They didn’t have a chance to get as good a foothold maybe. But that’s more like a mechanical failure. [Laughter.]

A. Or if you were barring those chicks all along, and you didn’t leave any behind, you might lose it in that one spot.

Q. So word of the day, when we’re talking about hens and chicks, is monocarpic. It’s not something to panic about when one sees that happen.  The genus Sempervivum is probably the most common; shall we start there?

A. I have about 35 varieties, but I don’t list them all in our catalog.

Q. Oh my goodness.

A. There are some varieties that are a little stingy; they grow a little more slowly or don’t have that many offsets, or I have not put them in the best spot in the garden and they didn’t winter over as well.  One thing people should remember: they are so easy in a gravelly, rocky soil, or a poor, dry soil. But if you put them in your regular garden, they are often just too wet in the wintertime and they just sort of dissolve.

Which is a shame because they are evergreen, so there could be color all winter long, where you put them. You should perhaps tuck them in those gravelly spots where you have a view in the wintertime because they turn beautiful hues of purple and red and bronze.

Q. So the Sempervivum are the most familiar, and you said you have 35 kinds from the genus? [Above, Sempervivum ‘Topaz.’]

A. Cultivars, yes. A lot are very similar, and that’s another reason I don’t list them all—because what is the difference between this and that? But in general I look for ones that offer more contrast, like ‘Commander Hay.’ It gets large—it forms a nice big rosette, so it’s bold, with more contrast when you’re using it with various other hens and chicks as well as the little sedums you might associate with it.

One that we brought back from the West Coast that they didn’t think was very hardy—they told me it was only hardy to 32F degrees, though I’d thought all the Sempervivum were pretty hardy—it’s called ‘Pacific Devil’s Food.’  In the wintertime and early spring, when the temperatures are cool, it’s like a chocolate-bronze color, and really nice for contrast.

Q. ‘Pacific Devil’s Food’—that’s a funny name.

A. Like devil’s food cake. There are many named selections now. ‘Royal Ruby’ [above] has a narrower leaf and true to its name is like a ruby color. ‘Pacific Blue Ice’ produces so many offsets, if you really wanted to use one as a groundcover in a gravelly area that would be a really nice one to use. Kind of a blue-green with hints of lavender and purple at the base.

Q. If we graduate then from the Sempervivum, is it Rosularia that’s next on our list?

A. It’s not a big genus. Often you can tell plants apart in the plant world by looking at their flowers. Rosularia has pale yellow flowers—and usually you don’t see yellow flowers in the Sempervivum. Usually they’re shades of pink and pinkish-lavender. [Above, Rosularia muratdaghensis.]

They’re a little more fussy, and again, sharp drainage is the key to growing them.

They’re great in rockeries and in troughs—alpine troughs. I’ve lost them in my own rock garden, so I keep mine going in clay pots that I overwinter in an unheated greenhouse. Some people call them alpine houses. Little houses where you can keep the temperatures just above what it is outside, but because of the roof over it, and the plants are not getting rained or snowed on, you can kind of control how much moisture they’re affected by in the wintertime.

Q. Next genus on our quick tour of the “other” hens and chicks?

A. I like Jovibarba.

Q. It’s a funny name for a genus of plants, isn’t it?

A. I used to leave out the second B and call it “Jovibara,” and people would correct me that knew what I was talking about, and I’d go, “Oh, right.” [Laughter.] It has some sort of translation like “Jupiter’s beard,” not to be confused with the perennial Jupiter’s beard [Centranthus ruber].

I think there are three or four species in the genus Jovibarba. [Below, Jovibarba hirta.]

Q. I think you told me three.

A. I was just trying to remember if there was something added that I’d forgotten. They produce a lot of offsets too—certain species, at least. The species hirta and globifera produce lots of little rosettes. In fact they are called “rollers,” because they fall off very easily and roll away and root in. [Laughter.] That’s kind of cute.

Q. The rollers.

A. The species I think if the most stunning—and let’s see if I can get this to sound right—is heuffelii. Although it produces offsets, they’re so tight they’re actually on the same crown. In order to propagate it—to produce those offsets—you have to sever the crown. You know how other hens and chicks, the Sempervivum, have those stolons that sort of creep along the soil, so it’s an easy pickup to move around or pot up.

Q. It’s almost like they have a tether between them.

A. And the Jovibarba don’t. I wait till I absolutely need to transplant the pot, and slice them up. I have not tried this one outdoors. I’ve tried the others in the rock garden. But I think this one makes a nice specimen in a pot.

Q. Then there is the genus Orostachys? [Below, Orostachys spinosus.]

A. The one that is probably the best known is the species iwarenge, or Dunce caps is the common name.

Q. The dunce caps! [Laughter.] That’s funny.

A. They form little gray rosettes, and when they bloom, they erupt just like the Sempervivum, and then they die off. But they also continue to send up so many little offsets that as long as they are in a well-drained soil you have them coming along forever and ever.

There are a few other species, and there is some confusion. The taxonomists have decided that some of these plants should be classified as Sedum now, so I hesitate to go into it too much since I could be contradicting myself in a few minutes.

Q. What I am getting is that when Grandma had her Sempervivum they were Sempervivum, and that probably all of these other things were at the garden center at that time. Now we have a lot more choices. And some aren’t even hardy—what we call the “Mexican hens and chicks,” the Echeveria?

A. The Echeveria are not monocarpic. They will bloom, but then they will keep living. So one of the other common names for Sempervivum is “live-forever,” and the Echeveria actually do sort of live forever. They bloom in the winter and early spring, though there are a few varieties that are very free-blooming and try to bloom year-round. But it’s no problem when they try to bloom; some people just like the foliage, and remove the flower. I think they add some color, especially on a winter windowsill. [Above, Echeveria pulidonis.]

Q. How not hardy are they? [Laughter.]

A. They don’t like to go below freezing. In the wintertime, if you had a cool room that was sunny, without a lot of heat—they can take temperatures in the 30s.

Q. Using these: I mentioned that in England, there’s always a shed roof with the “houseleeks”—the original green roof. It’s so sculptural and textural. And they need so little—they don’t want a deep, rich, moist soil.

A. They need a very shallow pocket; that’s all they need. They’re the perfect plant for green roofs or crevices.

Q. And sometimes you see them the cracks in a stone wall—in an unmortared wall, like an old, wonderful effusion of them coming over the top of a wall.

A. I absolutely love that; it gets me so excited when I see plants creeping out of such severe rock crevices.

Q. How would you get that started if you had a wall that was unmortared, and had some pockets in the top? Would you put some medium in the cracks?

A. You’d try to get a little bit of soil to fill that pocket, and wedge it in. Sometimes you might need to prop it into place, especially if it’s very vertical. Just positioning little stones to secure it in place. You could even use floral pins, I suppose.

Usually, dirt falls into some of these crevices, too. And then, when the plants are really happy, sometimes they will just find their own way in there, attaching as they set off offsets.

Q. And some are going to be happier than others.  It seems like the plants know where the best spot is. Like you can put it in 10 spots and three of them will be the happiest.

A. I always look to see: “Oh look, look what that did there all by itself. I think I will help it a little bit and find a few more like it and see what happens.”

Q. You said you combine the hens and chicks, in the sharp-draining areas of the garden and also in troughs, with what kinds of other things? Give us some visual ideas.

A. If you really want to do an alpine-style trough, with miniature evergreens, you could use little miniature Hinoki cypress. I’ve had really luck with them being able to overwinter outdoors [in Eastern Massachusetts] with no other extra protection.

Of course all the little creeping sedums—Sedum dasyphyllum [above], Sedum acre, Sedum album—those little tiny stonecrops that just kind of root along. They have little runners that root along, and make the groundcover.

Q. Right, the groundcover. And then you’d have these little buns, or rosettes, of hens and chicks.

A. Exactly. Now that fairy gardens have suddenly become so popular…

Q. [Laughter.]

A. …miniature gardens. I think if I had called what I was doing a few years ago “fairy gardens,” people would have looked at me like, “Are you OK?” But now they’re catching on.

So what it basically is, is a miniature garden. So the scale: The miniature Hinokis form the trees, the evergreen trees in the forest. And something like Sisyrinchium—the blue-eyed grass, with small, iris-like foliage—and then the rosettes from Sempervivum or the Rosularia that give you that form. And then little creeping thyme or miniature Dianthus—and all the ones that I am mentioning are ones that I have had luck with them returning year after year in the trough gardens.

We make hypertufa troughs here—or we used to make them, really large ones. So they have a nice environment to keep going. But you don’t have to use hypertufa troughs; you could use any winterized container, any container you can leave outside all winter.

Q. When you come to my Garden Conservancy Open Day June 4, you’re going to do a talk called “Succulent Love,” and then do a container workshop. We were just talking about troughs; what about other containers?

A. Anything goes. I always remind people that they don’t need a lot of soil, so if you have a shallow container that you put, say, petunias in, and they would always be drying out because it’s shallow, maybe you shouldn’t use petunias and try succulents instead. They don’t want a lot of water and can go week if not longer without much all season long, so they’re good choices.

In the container workshop, the non-hardy perennial succulents offer so much color and diversity that they’re the perfect subjects for these containers. But that doesn’t mean that you can’t mix and match, say, the tropical Echeveria or Crassula with the hardy Sedum or Sempervivum.

Q. So even though you may have to give it different winter care—put it under cover like that unheated greenhouse you mentioned, somewhere to be protected—you could still combine them. Or you could disassemble them.

A. I talk about that: So it’s been super-easy all summer long, and it’s just gotten better and better, and now it’s September or October and you’re threatened with a frost. You think, “What am I going to do now?” If the container is small enough you can just bring the whole container into a protected spot, if you have some of the tenders in it.

That being said, in general that grouping—lovely as it is—will probably need to be lifted and divided in the spring anyway. So if you don’t have the time, just bring the whole pot in. But you could also just say, “I’m going to separate this,” and you have some hardy succulents that you just tuck back into the garden, and you can overwinter a very special Echeveria or Senecio that gave you height—and put those on your sunny windowsill for the winter.

Q. Not as we do with our other “investment plants” where I disassemble some pots and certain plants go in the basement, others in the garage, others stay outside in weatherproof pots, as you say. Now I want to drive across the Massachusetts Turnpike, turn off at your exit, and fill my car with succulents. [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 April 18, 2016 show right here. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here).

(All photos courtesy of Avant Gardens, used with permission.)