Dahlias are the crown jewel of late summer and fall.

Perhaps the most versatile flower one can grow in the home garden, dahlias have captured the hearts of gardeners for generations. In fact, you might call dahlias a ‘cult classic’ of sorts.

It seems only right to spotlight them today, covering their origins, range and care, as they (almost single-handedly) bring the lifeforce to my September garden.

Origin story

Native to the highlands of Mexico and Central America, dahlias have a rich history dating back to the Aztecs, who cultivated them for both their beauty and culinary uses.

Today, dahlias grace gardens around the world—but true to their southern origins, thrive reliably as perennials only in zones 8-10.

Bedding vs tuber-grown

Let’s start with the two key groupings of dahlias: bedding and tuber-grown.

Bedding dahlias are quite small in stature; you’ll likely see them for sale in bloom at nurseries or garden centers. I have personally found bedding dahlias to be mediocre performers that fade in the sun.

When I gush about dahlias, I’m talking about tuber-grown dahlias. You will very rarely see these for sale as plants at the nursery, but you can certainly find the tubers (similar to bulbs, resembling potatoes) available at garden centers come spring.

A mixed bag

The dahlia’s diversity is unmatched in the flower kingdom.

In the tuber-grown world, we find everything from petite, pom-pom-like "Pompon” shaped dahlias to firework-like “cactus” type dahlias to massive, dinner-plate-sized dahlias (aptly referred to as “Dinnerplate dahlias”).

Beyond shape, we have size—ranging from 24” to 60”plus—as well as color. Dahlias show up in nearly every hue on the color spectrum. From deepest maroon, to softest pink, to vibrant orange—not to mention a lew of multi-color varieties, I can guarantee there is a dahlia to suit every taste and garden.

No-fuss flowers

You know we love a no-fuss flower—and dahlias most definitely rise to the occasion.

Plant dahlia tubers after the last frost (Memorial Day weekend is the marker in my zone 6 area) in a full-sun location. Roots facing down, growth facing points up (most tubers will have started to sprout, making it easy to identify the growth point).

I water them after I plant, and that’s it. They thrive in my garden with virtually no care, even in dry conditions—and are especially tolerant of the exceedingly hot days we’ve experienced ad nauseam this summer.

Little of your love

While dahlias don’t require much, there are three practices that will ensure they shine their brightest.

1. Staking

   Dahlias can grow quite tall, and any above 36” require staking in my garden. I have made the mistake of not staking them, and they topple—though they do still grow from whatever position they find themselves in.

2. Pinching

   When a new dahlia plant is about 12” tall and has 3-4 leaves, you can pinch them. Use your fingers or scissors to pop off the top part of the stem, just above the third set of leaves. This will encourage side growth, and lead to a stronger, bushier plant with more blooms.

3. Deadheading

   Just like most flowers, dahlias benefit from deadheading—pinching off flowers that are dead or dying. We covered this in detail in Issue 26, and I demonstrate it in this video.

Overwintering and dividing

Because dahlias hale from the south, they are not tolerant of freezing temperatures.

To preserve your favorite varieties, you'll need to lift the tubers—ideally a day or two after the first frost of the fall.

If you’re willing to roll the dice, try keeping tubers in the ground and covering a thick layer of mulch, and a layer of hay. I experimented with this last year, and was surprised to find all of my dahlias returned this year!

Tubers will multiply in the ground, so lifting them gives you an opportunity to divide them. This will leave you with even more dahlias, or give you extra to pass to friends and family.

Dahlia tubers can survive in this way for many years—in fact I have friends that grow heirloom dahlias, passed down from generation to generation.

Growing in containers

Dahlias grow easily in containers—provided you choose the right containers, and the right dahlias.

Shorter dahlias will be your best bet for containers—those that grow around 36” tall. Make sure your containers are large enough, at least 10” but ideally 12” in diameter.

Just one tuber per container is necessary, as dahlia plants grow quite large.

🍰 Snack I’m craving

Every single recipe shared by ex-London chef turned farmer Julius Roberts.

His recipes are garden-inspired and simple, and look so tasty. As soon as our kitchen reno is complete, I’m trying a few!

🌸 Flower I’m admiring

I came across a ‘Sweet Summer’ panicle hydrangea while at the nursery this weekend.

Its flower heads were massive, with a few just starting to turn pink. The colors of this particular variety seemed clearer than other panicles I’ve seen—the white a more true-white than yellow, and the pink a more frosting light pink than the darker ink-blotches I usually see.

I had to pick it up—now to decide if it goes on the front hill or back hill!

Are you growing dahlias this year? Which varieties are your favorites? Reply and let me know—I’m always happy to share suggestions if you need them!

xx,

Courtney