WHAT ARE YOUR time-tested perennials—and would you like expert help selecting others that rate that status? It’s time to talk standout plants, and on that score: Maybe the only thing I miss about my former city life and an office setting is having colleagues. I used to work on a team that included other very keen gardeners, and especially around catalog-shopping time, we talked plants, plants, plants.
Now as a rural dweller I mostly talk to the birds outside, so Skype and phone sessions have to substitute. My friend Katherine Tracey and I got into it the other day–lots of, “Have you ever grown (fill in the blank)?” or, “Did you see the new color of (insert Latin plant name)?” and then wondering aloud if each one is really a good performer or not, and worth trying.
I thought it would be fun to bring all of you into the conversation, too, so once you listen to our chat, tell us your own powerhouse plants, in the comments.
Read along as you listen to the Feb. 15, 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).
Background on Kathy: When she and her husband, Chris, a master dry-stone artisan, aren’t manning Avant Gardens, their longtime retail and mail-order nursery in Dartmouth, Massachusetts—they are out helping others make, and refine, their landscapes. The nursery (which is also their home), as Katherine describes it is: “Intimate, but not fussy, with a wide variety of plants, but not one of this and one of that everywhere.”
my time-tested perennial q&a with kathy tracey
Q. Part of your “job”–or really a lot of your job, both as a nursery owner and garden designer–is to identify great plants that will do the job in the garden setting (not just look good in a photo in a catalog). It must be hard to resist every pretty new face. How do you go about selecting things? Do you trial them, or what’s the process?
A. I can’t resist trying out new plants, and so I do. I try them out and see how they survive, and not just one year but several. Of course each winter we have here in the Northeast is different. We might have a mild winter and things come though beautifully, and the next year not so well.
There are some plants that are still trying to prove themselves. Last year, for instance, we were taken by that new anemone that was introduced at the Chelsea Flower Show a couple of years back, a hybrid called ‘Wild Swan.’ It was reported to have bloomed all summer into fall.
It started to bloom a little bit in late spring-early summer, and then no blossoms for most of the season, and then it picked up again in the fall. So it didn’t quite live up to its billing, but maybe it needs a year to establish in the garden and might show off better the second or third season. Patience is in order.
Q. So you don’t always resist temptation, but give them the test and trial things—give them a little more time. I think sometimes do take a year or two or three to settle in. I’ve been in my garden 30 years—and I think you have, too.
Q. Shocking, isn’t it?
A. It’s fun to look at the plants that have been there that long, and maybe not so much fun to think about those that have come and gone.
Q. I remember going to a garden in Texas, John Fairey’s garden called Peckerwood that was part of the Garden Conservancy preservation scheme at one time. He had an area in the middle of one bed, and at first you didn’t know what you were looking at. Then you realized: It was a giant cluster, like an enormous pincushion but on a large scale, of plant labels—of things that had died, but he’d kept the labels and made them into this impromptu sculpture.
A. [Laughter.] Oh my goodness, a shrine to all the dead plants.
Q. And he made the bed so perfectly manicured like the plants were in there. It was hysterical. So yes, I know what you mean: lots of missing creatures.
I really have to renovate a big area in front of my house, a bed that’s maybe 15 or 20 years old, and when I look at it I get stuck. I think, oh, when I planted it originally it was X, Y and Z plants—but that was 20 years ago, and I don’t want to repeat or recreate it. I’m not living in a historic-restoration property or anything [laughter]; not some famous garden.
It’s hard for me to get past what was there, and imagine something new for it, and I want to use some new things. But again—I see the pretty new face and never know if it’s worth it. So I thought maybe we could talk about some of what I call powerhouse plants and you call time-tested plants, if not for that specific bed (although I may take notes!).
A. For sun, I go back to my all-time favorite plant for the sunny border, because it is so reliable. I think the plants that we planted approximately 20 years ago are still in the garden and have not declined in any way. This plant is Calamintha nepeta ssp nepetoides, and it is a calamint that doesn’t drop seed in my garden. I have heard people complain that calamint self-sows, but this particular form has not here—and it should if it was going to.
And it blooms from early July right through September and into October. It’s a hazy mound of white—airy little white flowers. It doesn’t photograph especially well, so it’s often overlooked in catalogs. It’s not till people see it performing in the garden that they go, “What’s that?”
I know it’s been around for a long time, but I am still amazed at the number of gardeners who don’t know about it and haven’t used it in their gardens, because it seems to perform in sunny, hot, dry summers as wells as cool, wet summers.
Q. So Calamintha nepeta ssp nepetoides—but we can just say it’s a calamint, yes? [Laughter.]
A. Yes, it’s a mouthful of a name.
Q. I haven’t tried it, but it may find its way into my “needing to be restored” bed. What’s the next plant?
A. Let’s talk about a few more sun plants, and then we can talk about some shade plants. A plant that was new to me about five or six years ago is ‘Blue Star’ Kalimeris: Kalimeris incisa ‘Blue Star.’ It’s in the Aster family, but it begins blooming in June, and continues throughout the summer without deadheading. It’s a nice shade of lavender-blue.
The flowers are not each perfect, and sometimes that might throw people a little bit, because they seem to fade a little unevenly. You can do a little clipping if you want to, to freshen it up. It is a pretty well-behaved plant and grows about 18 inches tall. We’ve had it in the garden for five years and it hasn’t sulked at all—it comes back strong. It’s a candidate for the time-tested plants list, in my book.
Q. Does it help kind of knit together designs—is it an in-between plant, not groundcover or tall?
A. At 18 inches you could use it in the front of the border, or the middle. Definitely one of them is not going to make as big a statement. If you use three or five or six in a group, it will have more impact.
Q. Do you find that pollinators seem interested, if it’s an Aster relative?
A. It’s a magnet for butterflies and bees.
Q. I keep wanting to jump in and tell you my plant list, but I’m going to suppress my thoughts for a moment—because we could go crazy, you and me. [Laughter.]
A. If you’ve grown something I mentioned and want to give it the thumb’s up—or say it didn’t do so well…
Q. No, so far I am 0 for 2 on these, which is amazing.
A. Another one that is more for fall, but looks good all summer long, is a dwarf, Vernonia lettermanii. It forms a clump with fine linear foliage resembles threadleaf Amsonia, except a little but more compact. And this foliage looks good all summer. In September, it has clusters of purple flowers, and this too is attractive to bees and butterflies.
Q. When you said Vernonia, the only ones I have grow the species is not lettermanii, but noveboracensis—the New York ironweed—and they’re like an aster in flower, but super-tall, way up high, like taller than I am. This one’s quite different.
A. It is. The foliage on this one is more civilized. The tall Vernonia really is more of a candidate for the wild garden. It’s big, it’s blowsy; it forms these huge clumps. It is a great plant, but the dwarf ironweed I just mentioned is much easier to integrate in a mixed border. It can go with shrubs as well as other perennials.
Q. It’s so important as we think about wanting to support more pollinators in our gardens to have things blooming for as long a season as possible. In the Northeast, where we garden, that could mean as early as March or early April, and as late as November. The more things we add to the end of the season the better.
And now I’m 0 for 3, Kathy.
A. Wow. [Laughter.] Well, we talked about one the other day that I think you said you’d had, but that maybe it’s not in your garden any more or perhaps isn’t what it used to be. I still have two forms of it in my garden, and it’s Lespedeza thunbergii, the Japanese bush clover.
Although technically it falls into the shrub category, we treat it as a perennial up here in the North, because most of the wood gets cut back to maybe 6 or 8 inches in spring, and without any problem at all it flushes out and gets quite tall by the end of the season.
By August, it’s 5 or 6 feet tall, cascading with pea-like blossoms. There is a lavender-pinkish form called ‘Gibraltar,’ which is probably the most common, and then there is also a white form called ‘Avalanche.’ They attract butterflies and bees, and also the hummingbirds frequent it all the time.
Q. Well I can tell you from first-hand experience that it is also extremely attractive to bunnies—to rabbits. [Laughter.] I’ve had the lavender one, probably ‘Gibraltar,’ which is kind of a big mound, like a shrub. I’ve had it for easily 15 or 20 years—so long I don’t remember when I got it.
It’s fabulous, and you can see if from a great distance when it’s in bloom, so it kind of draws you across the yard to that focal point in that fall period [above in Margaret’s garden, a purple mound way across the yard]. Except that the last two years I had a lot of rabbits, of cottontails. For some reason, this was incredibly attractive to them.
They not only ate it once when it came up, but they did it again and again. As we know, a plant will resprout once, usually, but if you keep getting your head cut off you run out of energy.
I think what I will see this spring—since the rabbits were asked to leave—is some life in it, but maybe not enough. I might have to dig the whole thing out and replace it, and I will replace it because it’s such a showy thing at a great time of year.
A. It is. It doesn’t need to be on a slope or over a retaining wall, where it can cascade, but that is a great way to display the plant. I’m so sorry that the rabbits attacked it.
Q. And after all those years—what a wacky thing. We had a very dry year, especially in May, and everything succulent was just getting its head chopped off. I’ll get another one, or two or three.
Any others for sun?
A. One other I’ll mention: Crambe maritima, the sea kale.
Q. Oh, yes, sea kale.
A. This is a gorgeous foliage plant, with powder-blue cabbage-like leaves. The shoots in spring are edible, and it’s treated as a vegetable in Europe. I haven’t tried it myself, but it’s in the Cabbage family; it probably has that kind of flavor.
It blooms in June and July, and has these large sprays of white flowers. It, too, is attractive to bees and butterflies. It’s a good plant to use in the front of the border, and it likes hot, dry, sandy soils—in fact it’s native to the North Atlantic maritime region, probably the coasts of Ireland and England.
Q. Where I first saw this plant was at the garden of the late artist Derek Jarman, who has a seaside garden that a whole book has been written about. I think the garden is still preserved. I thought the sea kale has been planted there as an ornamental plant, but it was growing wild. [2007 photo of Jarman’s garden with sea kale in right foreground, by Wikipedia User Jasper 33.]
A. It’s hardy up through Zone 5, so there is no reason why it’s not being grown in more gardens.
Q. It’s beautiful. Who’s next?
A. Let’s talk for partial shade, and some of these plants can take full sun if they’re getting enough moisture during the growing season. One of the newer Brunnera on the market that has impressed me is the form ‘Alexander’s Great.’
Q. Is this the one that I see in catalogs with some guy who has his arms around it, as if to say, “Look how big the plant is, it’s as big as a person.” [Laughter.]
A. That was the marketing photograph that got distributed among all the people who were selling it. All of us growers buy it in as little starts, and grow it on in our own soil mixes.
It has the variegated foliage similar to ‘Jack Frost,’ but the leaves do get larger. I’ve had it now for three years and the plants have come through each winter beautifully, and it blooms in mid-spring with those electric blue forget-me-not flowers. As you and I have talked about, it’s an odd color in the garden because most of our blue shades have a lavender tint to them, and not electric blue.
But after it gets done blooming, all you need to do is cut back those flowering stems and the plant will flush out with some new foliage. Then the foliage looks good all summer, right into the fall. It does get some size to it, and gives you that hosta-like boldness in the garden, but that the deer are not especially fond of.
I know that so many of us are fighting deer, and when we can find something that the deer are not so happy with, that offers us an alternative to more of the time-honored plants like hosta.
Q. Big, bold Brunnera ‘Alexander’s Great’ for a part-shade, part-sun kind of a situation.
A. It doesn’t like soil that is really dry.
Q. Makes sense, with those big leaves.
A. Another one to go along with it, though I wouldn’t plant them next to each other because they are both variegated—with two different forms of variegation—is Symphytum ‘Axminster Gold.’
Q. That sounds like a comfrey.
A. It is, a variegated comfrey. You don’t grow this from seed to get the variegated form, but it needs to be divided—that’s the only way you will be able to have more of this plant. And it produces big, bold gold and green deer-resistant foliage. In flowers in late May-early June in my garden, maybe a little earlier farther south.
It has tiny little bells, blue aging to pink, that are sweet enough—the bees and butterflies like it.
One point I should mention: Here is an example of a plant that in order to keep it looking good all summer into the fall is to cut back those flowering stems that have a lot of foliage on it, and then the plant will flush out with a fresh display of leaves for the summer into the fall.
Q. I did badly with this plant. This is one where I got it when it first came out—and I think that’s one of the things as we said earlier with the anemone. Sometimes a plant is so new and maybe it’s not quite ready for prime time. Now it’s been known longer and propagated longer and I suspect I’d do better with it now, based on your experience and the experience of other experts. So I may give it another try: variegated comfrey.
What plant is next?
A. How about Aralia cordata ‘Sun King?’
Q You know I love aralias [above, a young-ish ‘Sun King’ in Margaret’s garden].
A. Another deer-resistant plant for shade.
Q. And this is a big, bold thing.
A. It takes few years to get there. People have to have a little patience when they grow this plant. Although I use it in somewhat shady gardens, it should get around 4 hours of sun to have a good gold color. If it’s in a lot of shade, it’s more of a pale greenish-yellow, not quite as exciting.
It does bloom in late summer, with white spherical flowers that are followed by black fruit. And again: deer-resistant.
Q. This is a great one: statuesque. My older plants of this are easily 5 feet tall in bloom and maybe 4 feet when not in bloom—big, big plants.
A. You’ve had them for a long time.
Q. I got them from a friend in the nursery business years and years ago, and so yes, I have some very old plants.
Want to try to tuck one more plant in before we’re done?
A. What about an ornamental grass?
Q. Oh, good.
A. It doesn’t get much publicity because maybe it doesn’t photograph as well as maybe the big clumping of Miscanthus that are sold everywhere. This grass that I am talking about is little bluestem.
Q. I love it.
A. The Latin name—I’m never sure if I’m saying it right: Schizachyrium scoparium.
Q. “Little bluestem” is good.
A. For me in the summer it’s just a nice upright thrust of powder blue foliage, and then in the fall it starts to change color. It takes on some purple-reddish tones, and then it holds on well into the wintertime, with wonderful amber color.
There are new forms coming out, and last year was the first year for us—we tried a cultivar called ‘Twilight Zone’ [shown], which has much earlier in the season some violet-infused with that powder-blue coloring, and then it changes to those more reddish tones and amber in the fall.
Last year was the first year for that, and so far it seems a little less vigorous than the species. This is a great grass to use en masse—it needs more publicity, so I’m glad we’re giving it a little publicity.
Q. I love little bluestem, and have been favoring it and cultivating it up on my hillside over many years.
Will you come back and talk shrubs next time?
A. Sounds good.
win a $50 avant gardens gift certificate
KATHY TRACEY has donated a $50 gift certificate from Avant Gardens (a seasonal sponsor on A Way to Garden) for one lucky winner. All you have to do to enter to win is answer this question, entering your reply into the comment box at the very bottom of the page, scrolling down beneath the last reader comment (NOTE: THE GIVEAWAY IS FINISHED):
What are your time-tested perennials, or as I call them, your powerhouse plants? Tell us where you garden, too (location or Zone), for perspective on your choices.
Feeling shy, or have nothing to share? Just say “count me in” and I will include your entry–again, put it in the box-like form at the bottom of the page! Good luck to all. I’ll choose a winner at random after entries close at midnight Sunday, February 21, 2016.
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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 Feb. 15, 2016 show right here. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here).