Mid-Atlantic Regional Reports

A Low-Stress Approach to Growing Dahlias in the Mid-Atlantic

When you garden outside of dahlia’s hardiness zone, an annual approach might be the best way to get gorgeous cut flowers

bouquet of pink and red dahlias
If you've dreamed of enjoying a diverse array of beautiful dahlia blooms inside and outdoors but dread the idea of digging up all those tubers every fall, there is an easier way. Photo: Maureen Robinson

My earliest memories of dahlias (Dahlia spp. and cvs., Zones 8–11) revolve around my grandfather, who grew them with gusto. His plants were neatly laid out in rows in the vegetable garden—cutting flowers, accessible for harvest, rather than specimens dotted through the borders.

My grandmother was the one to arrange them for the kitchen table or church bouquets. The vibrant arrangements were so exuberant. Dahlias are divas, and they command attention.

As for cultivation, I knew that the tubers were dug out and brought in each winter (this was Ohio), but it all seemed a bit mysterious, and it was a long time before I attempted to grow them myself. When I did, I initially thought that my approach was cheating, but I’ve since decided that my method is perfectly valid. I hope you’ll agree.


Dahlia Fun Facts:

  • Dahlias are octoploids! This means they have eight sets of each chromosome, which explains their potential for such diversity.
  • A true black dahlia is elusive. The closest we have is a deep blackish red, à la Chanel Rouge Noir (picture Uma Thurman’s nails in Pulp Fiction).
  • It’s almost physically impossible to resist putting your hand around a pompon dahlia, according to my personal research.

deep red, or black, dahlia bloom
While technically red and not black, dahlias like ‘Lights Out’ can still bring a moody and formal look to your bouquets and borders. Photo: courtesy of Swan Island Dahlias

Treat Your Dahlias like Annuals

Here’s my simple tip: treat your dahlias like annuals. This means you have two options each year:

Option 1: Order tubers online or from a catalog

After poring over catalogs and lamenting that you can’t have one of everything, finally select your favorites and place the order. Chelsea Belle of Bee’s Wing Farm in White Post, Virginia, suggests looking out for one or more of their bestsellers: ‘Sierra Glow’ (a salmon-colored dinner plate), ‘Isabel’ (a lavender ball), and ‘Blizzard’ (a white waterlily). All three varieties are particularly good in a vase, with long stems and good staying power.

three different varieties of dahlias
‘Blizzard’, ‘Isabel’, and ‘Sierra Glow’ are all great cultivars that make wonderful cut flowers. Because of their productivity and popularity, they’re also easy tubers to source, so you can spend more time enjoying these dahlias and less time finding them. Photos: Chelsea Belle

When the time is right for your zone, growers will ship your order. Bee’s Wing Farm recommends tubers be planted in late April or early May for a late bloom period: “hot start, cool finish,” which means fewer insect problems and longer lasting blooms. Whatever you do, make sure you’re past the frost date for your zone.

When my tubers arrive, I follow the grower’s instructions regarding depth and orientation. I opt to plant them in large troughs because, again, it’s easy, and anyone with a few square feet of outdoor space can add a container. Then I water them and watch the plants grow. Pinching them back will promote fuller branching and more blooms but is not a necessity. Your plant will just have fewer flowers. I also implement the “Florida Weave” for supporting these tall growers and learned to use “hilling” for sturdier plants (see Top Tips below).

Next, I thoroughly enjoy the blooms, on the plants and in bouquets, and finally—that’s it. I leave it to chance as to whether the tubers survive the winter, which they rarely do. In other words, I treat them as annuals.

staked dahlia plants
Treating dahlias like annuals will eliminate one of your chores, but providing some support is nonnegotiable. Whatever technique you choose, keep mature height in mind, as these plants can grow quickly during the heat of midsummer (exactly when you don’t want to be fussing with extending your stakes). Photo: Matt Mattus

Option 2: Buy plants from the garden center

Sometimes, spring slips by and you realize that you forgot to plan ahead. No sweat—just wait for dahlia plants to be available at your local nursery. Gush over their beauty, pick your favorites, and plant them as desired.


Top Tips from Bee’s Wing Farm:

Have you heard of the “Florida Weave”? No, it’s not a line dance, it’s a strategy for trellising plants with stakes and twine. Most associated with tomatoes, this method is basically a horizontal basket weave: in front of one plant, behind the next, down the line and back again (now it sounds like a square dance). Repeat each time your plants get tall enough to need more support. This will work for plants in the ground or in a long trough.

Use the practice of “hilling” for sturdier plants. As with potatoes, this involves building up a little hill around the base of the young dahlia plants, maybe 4 to 5 inches high, covering the first few leaf sets.


Maybe someday I’ll dedicate more time to my cutting garden, but in the spirit of “good enough over perfect,” I’d rather grow dahlias this way than not at all. I asked Chelsea what she thought about this, and she gave her stamp of approval—let’s just enjoy more flowers! As for those lamenting my lack of craft, I double down with this: I also buy pre-chopped mirepoix, but, man, are my soups delish.

storing dahlia tubers in a newspaper-lined crate
If you find the time to attempt some overwintering, storing tubers in cardboard boxes or wooden crates lined with newspaper and filled with peat moss or sawdust is a safe technique. To learn more about storing dahlias, check out this video: How to Dig, Divide, and Store Dahlia Tubers. Photo: gapphotos.com

Find more dahlia advice and inspiration:

 

Discuss this article or ask gardening questions with a regional gardening expert on the Gardening Answers forum.

And for more Mid-Atlantic regional reports, click here.


Maureen Robinson is president of the Washington, D.C., Maryland, and Virginia chapter of the Association of Professional Landscape Designers (APLD).

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