5 Tips For Growing Dahlias

by Alice White Walker
polaroid photo of sharon santoni on top of a dahlia

Cactus, waterfall or pompom, there are so many variations out there to brighten every garden. While they are relatively easy to grow, here are some tips for growing dahlias by our Editor and longtime flower fanatic, Sharon Santoni.

#Tip 1: Pick your flower carefully

While the dahlia family offers a lot of choice, there’s a few factors to consider before your dahlias reach full size.

Dahlias can be very big. Their average size is 1.2m, with some cultivars growing almost 2 meters tall! They like to have space around them to develop well and the large varieties will need to be staked.

If this sounds too big for your garden, then there are plenty of shorter varieties available, that are full of color and every bit as generous as their taller cousins. Almanac is a great guide for looking at different varieties and colors, as well as more tips for growing dahlias.

a view of the dahlia color garden at chateau de la bourdaisière

#Tip 2: Timing is essential

Because dahlias grow best in mild and moderate climats, you’ll need to wait until all the pinch of any spring frost is over before planting.
A few weeks after you pot your tomatoes is usually a good moment. You’ll see why they go so well together at Château de la Bourdaisière (p46, Sept.Oct)!

You can also get a head start by potting and setting them indoors for the first few weeks.

#Tip 3: When to water

One of my best tips for growing dahlias is to understand their hydration needs. Dahlias don’t need a drop until they start to sprout. But once they show, you’ll need to give them a lot of TLC.

I usually leave the sprinkler on for around 30 minutes, two to three times per week, to make sure they’re properly watered.

cafe au lait dahlia at chateau de la bourdaisiere

#Tip 4: Cut to cultivate

The more you cut dahlias the more they will grow. Which means you can create lots and lots of beautiful bouquets. Do take a look at the special winter arrangement that we made for My French Country Home‘s Sept-Oct 19 issue.

a range of cut dahlias waiting to go into a bouquet

#Tip 5: To lift or not to lift?

Most people believe you need to lift your dahlia tubers each winter and keep them to replant the next spring. This is a lot of work, and if your garden is not too waterlogged during the winter months you may be able to avoid that step.

If you decide to leave them in the ground, cut the stems back to about 15cm, and tie a tag around the protruding stalk with the name or color of the dahlia written clearly. Mulch at the start of winter and again early spring.

However, if you decide to lift the tubers, then make the most of the winter to divide them and multiply the dahlias for the next year. Lift and wash the tuber. Look carefully to find the ‘eye’ on the tuber legs, and cut carefully, leaving at least one ‘eye’ on each new piece. Store in a cool, dark place, covered in sand. Bring out to plant after the end of the spring frosts.

Make the most of planning your dahlias for next year, because we think they’re fall’s best flowers every year!

Do you have any other tips for growing dahlias? Let us know in the comments below!

Want more? Order the Sept.Oct issue here

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