The first of two comprehensive blog posts on growing dahlias in your home garden. This post covers the basics including our favorite varieties, tips on site selection, tools you’ll need and a tried and true pre-sprouting technique.

Well gardenologie friends, it’s here! Our dahlia primer. So many of you have asked for help on growing dahlias that we wanted to get you this information early in the season so that you can plan for your best dahlia season ever. Because growing dahlias is such an incredible and detailed journey, we are breaking down the information into two blog posts. This first post is going to help you start your plants off right and we will follow up with best growing and harvesting practices in the next post.

Why grow dahlias?

Dahlias are native to Mexico and Central America. They have been cultivated for their tall strong stems, the beauty of their blooms and the romance of them as both a garden and cut flower. You’ll want to grow dahlias to challenge yourself and to add beauty and color to your outdoor space. A highly rewarding crop that requires some effort, dahlias are simply the best showstopper flower that we know.

Dahlia Sizes

Dahlia blooms come in many different sizes and shapes and there is a tangible benefit to growing a variety of dahlias as they will add texture to your cut flower arrangements and bouquets. The largest of the dahlias exceed 25cm (10”) in diameter while the smallest are but 5cm (2”) across.

Get to know tubers

Most home gardeners and flower farmers alike grow dahlias from tubers. The tubers are the root system of the dahlia that are harvested and divided in order to create exact clones of the mother plant. The tuber is the plump part or the root and above it is the neck and the stalk. Above the neck where the stalk has been cut back you’ll find the eyes. Eyes must be present in order to propagate dahlias and they are where new shoots will emerge. In the image below, the eyes are the small green nubs on the tuber.

Choosing your tubers

Tubers are sold by breeders and big box stores alike and are generally sold to the public in late winter and early spring. There is not much advantage to buying your dahlia tubers any earlier as you will need to store them and they have very specific and somewhat tricky storage requirements.

Tubers should be firm and never mushy or showing any signs of mold. The tubers you purchase will need to have the neck intact in order for any eyes located above them to grow. If you come across a tuber with a broken neck, it is not viable and you should not purchase it.

Our favorite dahlia varieties

While there are many different petal configurations and sizes of dahlia blooms, this section is entirely subjective. There is no right or wrong dahlia to grow and we humbly offer you some of our favorite varieties. If you intend to use your dahlia blooms as cut flowers and arrange them, you might keep in mind the palette of the varieties you choose.

Our favorite varietals include:

Bacardi: Raspberry tones on white large blooms.
Boom Boom White: Beautiful uniform blooms that are incredible for wedding work and bouquets.
Break Out: Early blooming and very large. Pink outer leaves petals to soft yellow inner petals.
Café au Lait: Large light rose and dusky caramel colored bloom that is beautiful and versatile.
Chilson’s Pride: Lovely mid-pink tones that make it a crowd favorite.
Cornel Bronze: Orangey goodness with beautiful ball shape.
Ferncliff Copper: Peachy copper tones that are well loved.
Ivanetti: Ball dahlia with a lovely dark red tone.
Jowey Nicky: Prolific smaller blooms with a pinky-peachy hue.
Labyrinth: Very large beautiful decorative dahlia with pinky raspberry tones.
Linda’s Baby: Popular variety that blooms well.
Maarn: Rich orange color that bloom consistently.
Otto’s Thrill: Very large dinner plate dahlia that has a lovely pink hue.
Polka: Anemone variety with truly unique with yellow poofy centers and white petals with pink.
Peaches ‘N Cream: Wildly popular peachy blooms that are almost impossible to find.
Shiloh Noelle: Massive blossoms with pale pink and lavender colored petals.
Silver Years: Mid sized blush pink blooms that mix well with other dahlias.
Snoho Doris: Peachy apricot tones that are a larger ball variety.
Sweet Nathalie: More love in the blush colored blooms, this variety is simply stunning in its soft soft appearance.
Totally Tangerine: Pink and orange petals in a smaller dahlia plant suitable for container growing.
Wizard of Oz: Mini ball variety that is prolific and pink.

An entire module is dedicate to growing flowers, including Dahlias, in our A Year in the Urban Garden Master Class. We also cover flower arranging. Check out the Master Class page or contact us if you have questions about the program. You can also book a Discovery Call and we can discuss if the program is right for you!

Garden site selection

Be sure to pick a very sunny spot in your garden where you plan to grow your dahlias. A minimum of 6 hours of direct sunlight is needed for these beautiful flowers to thrive. Dahlias will require staking and at least 60cm (24in) of space so be prepared to dedicate enough space for your blooms.

Planting out your dahlias vs starting them indoors:

In regions where warm summer months are relatively short (Zones 7 and below) it is recommended that you start your dahlia tubers indoors before planting them out. This will give your plants a better start to the season and ensure that you have abundant blooms as early as possible.

Starting your dahlias indoors

You’ll need:

Potting mix
Dahlia tubers
Aluminum lasagna trays
Plant markers

Tubers should be started indoors 6-8 weeks before you plan on planting them out. They should be planted out after all chance of frost has passed so be sure to give yourself an ample buffer after the predicted last frost date.

Fill your lasagna trays with 2” of potting mix that is lightly dampened.
Place your tubers horizontally with any visible eyes facing up.
Lightly cover the tubers with your potting mix but leave the eyes of the tuber exposed.
Trays should be kept barely moist as you don’t want the tubers to rot.
Placing your trays in a warm space will help them sprout.
Be sure to use your plant markers to label the different tubers you have in your trays as they may all look very similar when sprouting.

Once it is nearing the time to plant your sprouted tubers out in the garden, you’ll need to harden them off. Start by taking your trays outdoors one hour in the shade on the first day, building on duration outside and exposure to the sun over seven days.

Stay tuned for the second blog post to learn how to plant out your tubers, stake your plants, protect them from insect damage and harvest your brilliant blooms! Be sure to sign up for our newsletter to get timely updates and information on when Part 2 will be released.

Dahlia Growing Guide - Part 1