IT’S PREPOSTEROUS just how many feet of stem and foliage sprout from each little annual vine seed, and even wilder are the fancifully shaped flowers with charming names like love-in-a-puff and cup-and-saucer and Spanish flag. Some favorites are brightly colored hummingbird magnets, too, and others (think old-fashioned sweet peas) are intensely fragrant–just making them even better garden choices. Growing annual vines and climbers, with Marilyn Barlow.

I got my first glimpse of what have become my seasonal favorites almost 25 years ago, in the Connecticut garden of Marilyn Barlow, when she was starting Select Seeds (which I’m proud is an occasional advertiser on A Way to Garden). Then, the “nursery” was Marilyn’s yard, and the “office” was her kitchen table. And then, I hardly knew any of the vintage plants, climbing or otherwise, that Marilyn was collecting.

Though Select Seeds’ focus is on oldtime plants or ones with an oldtime look, the nursery has taken an increasingly forward-looking approach to environmental practices.

On the path toward organic growing, says Marilyn, use of neonicotinoids and other systemic chemicals has been completely eliminated. “Right now we’re growing naturally, with the plants and with the seeds that we do grow here,” she explains. “We use predator insects as the main way to control pests, and if we need something else, we use a product that’s approved for organically certified production.”

A 15kw solar array tops the warehouse, and three 1,500-gallon tanks underground in the greenhouse area collect rainwater off the roof. That is cycled that back up into the greenhouse benches to “flood” or bottom-water the flats and pots, and, “then it goes from the benches back into the tanks so we’re not dumping any kind of fertilizer on the ground,” she says.

But what brought Marilyn to the radio show was not talk of conservation, but of climbers–annual ones.Read along as you listen to the April 13, 2015 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).

The transcript includes many “extras” that we didn’t have time for in the broadcast. Enjoy!

read/listen:

my annual-vine q&a with marilyn barlow

Q. Let’s start with some general vine-and-climber 101. Not all are created equal–or climb the same way.

A. One of the great things about annual vines is that they’re not permanent. You can create a structure that they’ll cover. You can maybe hide something that you don’t want to show to your garden visitors.

Q. [Laughter.] Oh, that never happens to me, Marilyn—that I need to conceal something.

A. You could screen the compost area, for instance—so they’re useful in a lot of different ways, as well as being fun to grow, and an adventurous kind of pursuit.

Q. Some have tendrils, some twine…so they’re not all the same that way, in the way they support themselves, are they? [Above, Basella rubra, left, twining and Asarina climbing.]

A. The sweet peas and the cup-and-saucer vine (Cobaea scandens) have tendrils.They need a little bit of help at the very beginning, because the tendrils will wrap around something thin, so you need something fairly small to start with. But once they get a hold, they’re on their way up. And the cup-and-saucer is a pretty aggressive grabber. [Below, flower details of Cobaea and of ‘Black Knight’ sweet pea.] 

Q. Like string or…?

A. You could use string, but better is twiggy brush—little clippings from prunings.

Q. But at the beginning they’re not looking for something like a thick bamboo cane.

A. Nothing that big; you have to give them a helping hand, just to get going. They reach it, and then they’re on their way.

Q. What about some vines that don’t have tendrils?

A. The nasturtiums, for instance. Runner beans will twist, and morning glories will twine quite aggressively—they have strong, muscular stems that will pretty much climb on things. In nasturtiums, the leaf stalks kind of twine on things. The petioles reach out and grab on.

Q. I think of annual vines kind of in groups—for instance, like sweet peas as being a world to themselves, and others that are hummingbird favorites, and so on. Shall we start with sweet peas? You have some amazing ones—including that really dark purple ‘Black Knight.’

A. That’s always a favorite.

Q. Very fragrant, too, yes?

A. Yes, it’s an old-fashioned grandiflora type. It dates from 1898, near the beginning of the craze for sweet peas at the turn of the century. Henry Eckford of England bred that one, one of 153 cultivars he personally introduced, and we still love it today.

Q. You sell sweet peas both as seeds and plants. So how do we grow them?

A. They fit in well with organic growing, because they like an organic soil: rich in humus, with a neutral pH—well supplied with bone meal and compost, rotted manure, lime…you name it. And all well dug in.

Q. Do we sow them when we do our garden peas?

A. Yes, about the same time, but we do them indoors. In New England, you might find you’re planting them on a nice day and then you get snow and rain—maybe a week of rain—so the seeds might rot if it’s too cold and too wet.

Mice also love those seeds and will dig them up and slugs and rabbits can finish off the newly emerging seedlings before they even have a chance!

Q. In cellpacks indoors or in 3-1/2 inch pots or…?

A. We put them in individual pots, three seeds to a pot. They come up very reliably that way. Then if space is an issue, as soon as you see them poking above the soil surface, you can put them outdoors to harden them off, and then transplant them once they’re up and growing at about 3-6 inches or so.

Q. We want to give them help to get started climbing. [Sweet peas on a rustic wigwam, and the variety Spring Sunshine ‘Champagne’ on plastic netting, above; below, rustic supports for vines at Montreal Botanical Garden.]

A. You don’t want to let them lay on the ground. You can use brush; I like brush, because if it’s a plastic trellis, for instance, at the end of the season how are you going to manage that plastic trellis, getting the little pea vines out of it?

Chicken wire also works well to support them as the thin wire allows the tendrils to easily catch hold. We also pinch once when they are about 6 inches tall to encourage some branching to fill out the planting.

Q. How tall can I expect them to be, and are they all fragrant?

A. All the ones we sell are fragrant or highly fragrant—there’s a little variation between the varieties–and they get to about 5 or 6 feet tall.

We have a new variety of sweet pea this year-the fragrant Spring Sunshine series. These are coveted by cut-flower growers for their large flowers and super-long stems and have been very popular with our customers. They were bred in England, but using old American varieties that are so much more heat tolerant –and earlier to bloom.

Q. How long do the sweet peas bloom?

A. It depends where you live, of course. At the coast of Maine, they might go all summer, with night temperatures dropping and it never getting too hot during the day. They’ll go much longer that way.

Q. And in warmer zones they are planted earlier and finish earlier.

A. And in intermediate areas, you might get two to four weeks of bloom, where in perfect zones perhaps all summer. Keep cutting the flowers for bouquets so they don’t go to seed, for that will also cut short the bloom time.

Q. I’m crazy about hummingbirds, so I love what happens in the later part of the summer and into early fall with some of the annual vines that hummingbirds like. Which ones have you noticed that they’re interested in?

A. They really do like the cypress vine and cardinal climber [above]—very small but very bright red trumpet-shaped flowers that are morning glory relatives. They’re very cute. They seem to flock to those.

I think they also like runner beans [below left].

Q. I’ve also noticed them on some of the Asarina [like ‘Wine Red,’ above right].

A. Yes, we call Asarina the climbing snapdragons, but they’re known by many names. Those do attract hummingbirds very well.

Q. They like the Spanish flag, too, Mina lobata or whatever it’s called now.

A. We still classify Spanish flag as Mina lobata, but it’s changed over to Ipomoea lobata now—but we’re kind of old-fashioned here in many ways. [Laughter.]

Q. You are, but in a charming way.

With cardinal climber and cypress vine [and Spanish flag, above]—they’re morning glory relatives, so do we soak the seed first? 

A. Yes, they have a hard seed coat like morning glories do, so a little soaking will help speed germination. And they’re tender annuals, so they don’t like cold weather, and don’t want to be started outside too early.

Q. So again in 3-inch pots indoors?

A. Yes, or a peat pot where you can just ease them out gently and transplant them once the weather has settled, and the nighttime temperatures aren’t still see-sawing up and down. You want to have 60 degrees at night—we’re talking the beginning of June in the Northeast, for instance.

Q. I find that the Spanish flag is such an extravagant late-season bloomer for me.

A. A lot of morning glory relatives are short-day plants—you have to wait until later in the summer for them to really come into their own.  And they all hate cool weather in spring, when they’re getting going; they sulk, like we do.

Q. The so-called black-eyed Susan vine, Thunbergia alata: It seems like there is a wider range of colors available lately.

A. I wish I had a lot more history about how they were developed. We have ‘African Sunset’ (very similar to ‘Blushing Susie’), which is a combination of warm-toned flowers. We also have the ‘Arizona Dark Red,’ a sort of burnt orange-red kind of color.  It has an even darker center like most of them do.

Q. And you have a white one with a black center. It’s a crazy-looking thing.

A. That’s one of our favorites. Black-eyed Susan vines are really suitable for growing in pots; they’re not huge vines, like cup-and-saucer, or hyacinth bean, or moonflower, which get quite large and are better suited to arbors.

Q. On my patio I have these big, low terra cotta bowls—like 30 inches wide, but low like a soup bowl. I put a bamboo tripod in the middle, tied together at the top, and I grew that ‘Arizona Dark Red’ up each leg, and I used at the mid-layer other annuals, like Coleus with similar colors, plus some other things I cannot recall, and draped Alternanthera down the edge of the pot. The vine became the upright element.

Are the Thunbergia easy from seed?

A. The seeds are fairly large, and easy to grow; we start quite a few of them indoors. They’re a good one for beginners.

Q. You have a Senecio confusus that I was curious about…

A. We’ve had the Mexican flame vine, the selection called ‘Sao Paulo,’ [above right] for a long time. It’s very popular—and more of what I call a sprawler. We grow it in pots, and it cascades over the pots.

Q. Could it be a hanging basket as well?
A. I think it would be good in a large hanging basket. It’s a real butterfly attractor; they flock to it.

Q. It’s a composite, or daisy-like flower, and orange-colored.

A. ‘Sao Paolo’ is a scarlet-orange, very rich and very pretty, and it has a big fluff in the center and that’s what the butterflies go for.

Q. There was another vine I haven’t grown in years, speaking of climbers that do well in pots: Rhodochiton [above right].

A. That’s pretty refined—we call it a refined vine. It stays nicely, shaped; it doesn’t try to get away. It doesn’t climb up to the top of your support, topple over, tip it over—it doesn’t go wild. It has these very showy flowers composed of a calyx, which is long-lasting, like a little umbrella, on top of the flower, which is tube-shaped.

Q. It’s like a clapper in a bell.

A. Right. Those showy calyxes stay as the old flowers fade and new ones come on, so you get more and more and more as the season progresses. And it’s quite frost-tolerant in the fall.

Q. I find that the Spanish flag last a lot longer than other things with that tropical look would be expected to; not into hard freezes, but well into the cool fall.

A. Some of those tropical things start out not wanting to be cold, but finish strong.

I think cup-and-saucer is also frost-tolerant, which is good because it tends to bloom midsummer on, so it will be one of the last things in your garden looking gorgeous in the fall. That’s a very showy one—and the leaves are really pretty, and the tendrils are a lovely violet.

Q. So what’s not to like about it? [Laughter.] Any others you want to make sure we have an eye out for?

A. I really like the canary bird vine, Tropaeolum peregrinum. Like a lot of these “annual vines,” it’s a tender perennial, but we grow it as an annual.

Q. And it does have these little canary birds—the flowers really look like birds. And nice foliage.

A. The foliage is the main selling point, because sometimes the flowers aren’t as abundant as you’d like—they are generally dotted about. But the leaves have this gray-green cast to them; a nice contrast to the bright yellow fringed flowers.

And the other one is love-in-a-puff (Cardiospermum halicacabum). It’s one of those adventurous things; a fun vine. The flowers you might not even notice; they’re tiny little white things. The leaves are shy and retiring; they don’t make a big bold statement. But the balloon part that encloses the seeds is very decorative. Then once that balloon ages and matures and turns buff-colored, you open it up and I think there are at least three seeds that are a pure matte black, marked with a perfect little white heart on them.

• Browse annual vines at Select Seeds, sold as seed and transplants

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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 13, 2015 show using the player near the top of this transcript. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here).

(Photos except cardinal climber courtesy of Select Seeds.)

more in-depth annual vine profiles

• Spanish flag
• Cardinal climber and cypress vine