growing begonias, with tovah martin

I’M ALWAYS LOOKING for ways to make my many houseplants, especially the fancy-leaf begonias, feel more at home year-round–especially through the hot, dry wintertime indoors. I asked author Tovah Martin, a begonia expert, for advice on these sturdy beauties (like ‘Kit Kat’ and ‘Palomar Prince’, above, left to right).

Tovah is the author of more than a dozen garden books including “Tasha Tudor’s Garden” and “The New Terrarium” and the “The Unexpected Houseplant,” and her newest, “The Indestructible Houseplant” (Amazon affiliate links).

Besides our love of begonias, Tovah (find her at her Plantswise Facebook page) and I share a commitment to organic garden practices, indoors and out,. And we are near-neighbors in the corner of the world where Connecticut, Massachusetts and New York’s borders come together.

Tovah says she emerged from 25 years working in Connecticut at the famed Logee’s Greenhouses with “a serious houseplant addiction.” She joined me on the radio and podcast (the transcript follows) to confess some of the sordid details of that affliction–and share some of her best insights into success. (That’s Tovah, watering, below.)

q&a: begonias and more with tovah martin

Q. Are you and your babies tucked safely inside, Tovah?

A. There’s one jasmine left outside—getting the chilling process he needs.

Q. A little tough love for that one first, huh? Is there any room indoors left for you?

A. No, I just get wedged in a corner. But isn’t it wonderful that you brush by these things all winter—and that‘s part of the therapy of it. I don’t know where I’d be without these plants I walk past in the morning. It’s like a garden indoors.

Q. I’ve had some that I have owned for decades—they’re like family.

A. And every year it changes a little bit—every autumn when I bring them in, it’s like a new little landscape. New ones come; old ones we wave goodbye to.

Q. I know you have a new book coming next year, called “The Indestructible Houseplant,” and I assume begonias are in it, yes? And did they feature in the current book, “The Unexpected Houseplant,” too?

A. Begonias are everywhere in my life.  Even though they have always been thought of as houseplants, you can grow them in unique and beautiful ways that’s a little bit off the beaten track.

Q. Hence the “unexpected” word in the title of the latest book.

Can we have a quick history of your affair with begonias? Did it begin in the years you worked at Logee’s?

A. Prior to Logee’s, I had no idea how many different types there were. I really only knew the ordinary wax begonias, the semperflorens group that is grown in the garden all the time.

At Logee’s I curated the begonia collection for 25 years, and that solidified the romance between begonias and me. Can you think of another plant that is as diverse?

Q. Yes, we should explain that there are various groups of begonias. It’s a genus with all kinds of forms.

A. And sometimes you think, “That’s a begonia?” But when you see it bloom, all is revealed.

There are several different types—the wax or semperfloren types, but historically other types have also become popular. Many people know the tuberous types that grow in the summer, with those great, huge fluffy flowers. They go dormant in the winter. I think those are the kings of the flowers for begonias.

And then there is a semi-tuberous group, which come from a caudex, and look a little like a bonsai.

Q. I love those oddball types.

A. There are also more upright or cane types, which just as the name says they jut straight up. The trick is to prune them to make them branch out. The leaves are like a wing—bat wings, feathery angel wings, that sort of thing.  Within that group are some that cascade down—scandent types. And then there are the rhizomatous types, like one of your favorites, ‘Marmaduke…’ [in photo below, at right]

Q. …which is kind of chartreuse with reddish spots and pucker and lusty growing…

A. …and kind of has felted, furry leaves.

The rhizome is a rootlike sort of a thing that creeps along the top of the soil, and send up the leaves. There can be upright versions, but most sort of creep along the ground. They have a great diversity of leaf shapes and sizes: ones just the size of a penny, and then one like ‘Marmaduke’ could be 10 inches across and some get even bigger than that.

Some have palmate leaves, others rounded, some curly.

Q. And the colors—they’re like a stained-glass window.

A. And the flowers usually happen later winter and early spring, and come up in a little scape. Not huge, and usually pinks and creams. The flowers aren’t the big things for those.

And then there are the Rex types.

Q. I’m here in the studio now with two thumbs pointing down. I see them at the garden center, and they’re so beautiful, but…forget about it. Do you grow Rex types?

A. They are tough to grow. I get powdery mildew, do you?

Q. I feel like the leaves start to sort of “melt” and decay, yes.

A. Unless they have fans going and so on, in the average home that you have to close up during the winter, people struggle with the Rex types. They’re very colorful with bands of reds and greens and metallic silver—but for me it’s mission impossible.

Q. I should say, I think the rhizomatous types make great holiday and hostess gifts, and I sometimes order ahead of when it’s too cold to ship, caring for them for a couple or few weeks before bringing them to someone. (Or I just give a gift certificate, for redemption later.)

So let’s go through the 101 on growing the rhizomatous types—shall we begin with their basic needs?

A. Rhizomatous begonias like indirect sun, so an east or west window is ideal. If growing them outside, it would be under a loose shade tree.

Across the board with begonias: They don’t like huge pots. They like to have their roots cramped a bit into smaller containers. I find that most begonia roots don’t go down, they go horizontally.

A shallow container is better than a deep one—like what we’d call an azalea pot.

Q. Slightly wider than it is tall?

A. That’s best for them, which goes into their next need: That they don’t like to be overwatered. They like to dry out slightly between waterings, so when you grow them in the shallow pot you are less likely to have soil lower down, beneath the root area, that’s damp. In the shallower pot you have roots throughout the soil that are drinking up the moisture.

Q. So you don’t want them standing in  saucer of water, either, right?

A. Growing inside, everyone has their way of staging plants, and everything has a saucer, or zinc trays or something like that. Try to avoid standing water—which is what you’re alluding to.

Q. Outside in the summer [above, some of my plants near the kitchen door], I take the saucers away, so in a rainy time they don’t stand in water, either.

A. I’m with you on that.

Q. Potting soil?

A. Back in the day we made potting soil for specific plants—a fern mix, a begonia mix, and so on. Now I use the same soil for everything—an organic potting soil. It’s not so hard to find organic potting soils nowadays. I use one that has compost added, so that it has nutrition in it. I don’t use a soilless mix, but believe in one with some soil in it.

So you’re giving it oomph under foot, you’re putting it in a pots that’s shallow so they’re not swimming in soil with no roots.

And in with this we should mention that our container needs good drainage. I do a lot of drilling [of holes in pots] but you couldn’t really drill a drainage hole big enough for begonias. They need really good drainage.

Q. And then we bring them into the house at season’s end…and they get a little angry at us. [Laughter.] Some of the bigger, older leaves will start to pale and drop. I confess I sometimes give haircuts to the ones that are in the worst throes–but what’s the optimal overwintering plan?

A. Some of the upright rhizomatous hybrid types, like ‘Little Brother Montgomery,’ [above] drop some leaves in the fall when you bring it in. And this is important: Bring them in early in the fall; they don’t like it at 40 degrees. Begonias would be one of the first plants you’d march inside in fall.

Try to give them a fair amount of humidity—don’t situate them near a heating vent.

Q. Many of the rhizomatous types will climb out of the pot and over the rim, with the rhizome looking like a giant caterpillar gone overboard. Oops, I guess I should have repotted already! Tell us how to read the plant’s signals and when and how to repot.

A. I repot begonias only in the spring—since winter is not when they are growing actively, and light levels are also low. To determine when to repot, check the root system. If the roots have filled the container with nice whitish, creamy-colored healthy, live roots—that’s when you would repot.

Q. Do I pinch off those “man overboard” rhizomes? [Laughter.]

A. Pinch is the magic word. If you don’t want them to get all unsightly and naked and gnarly, clip the little tips off those rhizomes, and they’ll start to make new growth by themselves, and you won’t have to go through the unsightly stage. You’ll nip that in the bud.

Those are easy to root with hairpins.

Q. Pin them down on the soil surface?

A. Yes, and they’ll make new plants.

A. With your new “The Indestructible Houseplant” book well under way, and due out next June, I wonder what other toughies besides begonias made the list?

A. As I was testing plants, I found more and more and more—and it went a little crazy. You’d be surprised at what many plants can really endure. I really put these plants through their paces.

Q. Tough love! Which made the cut?

A. Ivies, aspidistra, Aglaonema, agave, philodendron, euphorbia, sansevieria, old-fashioned geraniums…plants your grandmother grew.

Q. I was just listening and thinking, “My grandmother’s plants.”

A. But you can do it with so much more finesse. You can give them a punch, modern look that’s you.

Q. And compared to in Grandma’s time there are showier forms—variegated, for instance—and not just the one plain old green one.

A. Absolutely—with everything. There are many more agaves than years ago; I had no idea that there were so many varieties of Aglaonema when I started collecting them a few years ago.

some favorite begonias, from tovah martin

AFTER OUR radio chat, I asked Tovah to name some favorite begonias. “You’re asking for trouble if I get going on favorites,” she said. “It could go into infinity. But right now I’m growing these:”

• ‘Black Fancy’
• ‘Erythrophylla’
• ‘Bunchii’
• ‘Cowardly Lion’
• ‘Bethlehem Star’
• ‘Texas Star’
• ‘Fuscomaculata’
• ‘Beatrice Haddrell’
• ‘Stonewall’
• ‘Palomar Prince’
• ‘Zip’
• sizemoreae
• bowerae nigramarga

get the podcast version of future shows

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. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here).

enter to win ‘the unexpected houseplant’

I’VE BOUGHT TWO copies of Tovah Martin’s “The Unexpected Houseplant” to share with lucky readers. Update: the giveaway is complete. All you have to do to enter is answer this question in the comments box way down at the bottom of the page, after the very last comment:

What houseplant have you had the longest, and is your most reliable? (If none are very old, than what’s your favorite?)

My oldest are the Clivias that I’ve had for way more than 20 years–can it be 30? They’re divisions from a big plant that sat in my mother’s TV room many decades ago.

No answer, or feeling shy? Just say, “Count me in” or something like that, and I will, but an answer is better.

I’ll draw two random winners after entries close at midnight on Monday, November 24. Good luck to all. U.S. and Canada only.

• Again: Find Tovah on her Plantswise Facebook page or her website.

(Photos copyight Kindra Clineff, used with permission, except ‘Marmaduke,’ ‘Little Brother Montgomery’  and outdoor plants with water troughs, by Margaret Roach.)