growing dahlias – my do’s and dont’s and learning as you go

by Sharon Santoni

I’ve been growing dahlias here for six or seven years now. It started with a tuber I found in a bargain corner at the garden center, and which turned out to be the most beautiful café au lait! I was immediately hooked, and have been growing them ever since, in increasing quantities each year.

Like everything else in the garden, there is an element of trial and error in growing dahlias. It took me a while for example to understand that I can leave some dahlias in the ground in certain parts of the garden, whereas elsewhere I have to lift them because the earth is too damp during the winter.

Like so many others, I have admired the long beds of dahlias that populate Instagram like the one at Charlie McCormicks house in England. I attempted the same thing this year, planting 45 tubers along a 25 metre wall. On the whole it looks good, but I’m not quite there yet. The key seems to be staking the dahlias individually.

So, although I don’t consider myself a dahlia expert, here is my list of do’s and dont’s – learnt the hard way!

Lifting dahlias for the winter.

Yes, I know, it is what you are meant to do. And I have done it for several years, but it is a lot of work. Each tuber needs to be cut back and lifted. Washed clean of any clinging earth, labelled and allowed to dry before storing beyond the reach of frost and light. I’m lucky to have a dark wine cellar with space to store the twenty or so crates that were needed to stock the huge tubers.

You can forget about them all winter, but when the moment comes to replant, it’s easy to feel fainthearted. The realisation that the 50 tubers you dug up last autumn need to be divided, and you now find yourself with well over a hundred dahlias needing a home … it can come as a shock.

At the end of the day, you have to get to know your garden. If there are beds that are very damp during the winter you will need to lift the dahlias, but those that are well drained could be left. If you’re willing to take the risk of losing some over the winter rather than having the work of lifting and planting – this is your call!

Choosing the right spot

When planting dahlias, it’s important to understand how tall and wide they’ll be when they start growing. This year I accidentally planted some Bel Amour tubers at the front of a bed with a much shorter variety behind. The result is that the shorter dahlia is practically invisible. You also want to have easy access to each dahlia plant for deadheading, so don’t put them at the back of a very deep bed unless you can get in there with a secateur.

Water carefully

Dahlias don’t like to get too hot or too dry. Their leaves look a tad tired, and they have trouble producing as many flowers. The best way to water is a drip pipe – less wasted water and it goes straight to the root. The easiest time to lay down the drip hose is when you plant the tubers.

Deadheading

Deadheading needs to be done regularly in order to continue getting a healthy growth on your dahlias. If you let the plants go to seed, not only are they less pretty, but they also use a lot of their precious energy trying to grow the seeds instead of concentrating on exceptional blooms. And of course, the very best way to deadhead is to pick them before they fade and bring them inside for endless bouquets!

Take cuttings

it is very easy to multiply dahlias by dividing the tubers, but did you know you can also propagate by taking cuttings from the plant once the new shoots are about 10 cm high? Cut off small shoots, leave only the top two leaves and pot immediately around the edge of a large pot filled with good quality earth, already damp.

Stake your dahlias

Possible the most important step! Dahlias can grown 6 foot high, and their flower heads are heavy, especially in the rain. The ideal is a sturdy stake for each plant. Failing this, a grid system using a sturdy string zig-zagged between stakes. This year I used string and stakes along the bed, but it wasn’t as effective as individual supports for each plant.

Drying your dahlias

You may not know just how beautiful dahlias are when they dry! To do this, cut your flowers at their best blooming moment. Take them inside, away from direct sunlight, but not in the dark. They need plenty of air circulating, and the easiest way to dry them is to stretch a length of chicken wire along a ceiling space, and simply poke the dahlia stems – upside down – through the holes. In 3-4 weeks you’ll be able to create a stunning bouquet of dried dahlias that will last through the winter months.

22 comments

Joann Beck September 27, 2022 - 6:47 pm

What a lovely and enlightening article! You are quite the gardener and I appreciate your sharing your talents.

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Judi September 28, 2022 - 12:21 am

Do you have earwigs on your Dahlias because I do . They are awful.

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Sharon Santoni September 29, 2022 - 1:18 am

Hi Judi, I don’t seem to have that problem …. I’m sorry I can’t help you on that one

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Ruth October 1, 2022 - 2:14 am

I have seen gardeners put a small pot upside down on a stake near the dahlias, with some straw in it. This apparently attracts the earwigs to the decaying straw and dark place (which they like better than dahlia leaves). It also keeps you from poking your eye on the top of the stake when you bend over. 🙂

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Sharon Santoni September 29, 2022 - 1:17 am

thank you!

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Lin George September 27, 2022 - 7:44 pm

This is an excellent article. Keeping them in the ground over the winter is so much easier. At my last property I had some in a fairly protected spot with a wall behind them. I found that layering old carpet pieces over them worked well. I used outdated carpet samples that I got for free from a carpet store.

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Shiva Denis September 27, 2022 - 7:54 pm

Sharon, I loved reading your post on growing Dahlias. I fell in love with them the day I discovered Cafe au Lait at your home. I’ll never forget the beautiful table arrangement you created with freshly cut ones from your garden that day. If you have any tubers of Cafe au Lait needing a home I will welcome them with open arms.
Xxx Shiva

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marilyn September 27, 2022 - 8:18 pm

Your message is very timely. I was just online to find information on growing dahlias. I have about 10 in my garden, but want to dig them up this year and move them to my daughter’s garden. I love them, but may move and I know she would enjoy them and I could go pick from her garden. Thank you for your share on gorgeous dahlias.

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Yvonne September 27, 2022 - 9:45 pm

What a beautiful display!
Wonderful information on dahlias. I also love the Café sun Lait and planted them many years ago. This year I just ordered some for next spring and will rekindle my interest in dahlias. Thank you for the inspiration.

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Mary Ewen September 27, 2022 - 10:00 pm

Wonderful wonderful garden tips . I am just getting used to what our front and back gardens do since we have only been here 7 months and I hope to try to do some dahlias for they do make stunning arrangements! Thank you so much!!

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Kameela September 27, 2022 - 10:50 pm

They are gorgeous. I don’t lift mine as when I do they shrivel and die. Now I just leave them and take my chances

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Lulu GALSTON September 28, 2022 - 12:26 am

Beautiful flowers freshly cut and or dried for bouquets and do the deer relish them? Lulu

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Suzanne Nelson September 28, 2022 - 3:46 am

I grow to love Dahlias after visiting France and so I looked to plant some in Melbourne Australia. I managed to find some little ones and even those are so expensive in relation to other plants.

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Lorrie Orr September 28, 2022 - 5:42 am

I have never thought of drying dahlias. Mine are continuing to produce lovely blooms that I cut every few days and bring in to make bouquets. I’m always dithering about whether or not to leave them or to bring them in for the winter. A very informative blog post! Thank you.

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Patricia Guest September 28, 2022 - 7:41 am

Thank you Sharon for your informative post. You did not mention feeding them. Do you feed them regularly to get the abundant flowers?

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Pam Gillies September 28, 2022 - 11:14 am

Lovely article Sharon. I, too, LOVE dahlias and have two dahlia beds. This year I had lots and lots of buds but they just didn’t open up! Any ideas please ?

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Rhonda Reeves October 2, 2022 - 4:43 pm

Having just visited your garden, no one would notice what you call mistakes–it was beautiful and now I want more Dahlias next year. Thank you for the tip on drying as I had not thought of that.

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Shannon Grochowski October 27, 2022 - 10:11 am

Thanks for such helpful tips! I began growing them back in Montana years ago and had lots of earwigs in the petals. I’d scream each time I cut flowers. Now, in France, I’ve had luck planting them in containers, but look forward to having some earth soon. I’ll use your tips❤️

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Lucia Donahower October 31, 2022 - 11:50 pm

WOW! Your Dahlias are so beautiful! I love the single one you featured pink/white variegated and that yellow center. Can you share the name of it?
Frankly, they all are beautiful .
Thank you so much for your tips in growing them.
Many thanks,
Lucy in California

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dumpster rental woonsocket ri April 13, 2023 - 12:04 pm

Dahlia is a beautiful flower. Want to grow them on my own.

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peter hunt May 28, 2024 - 11:27 am

This will be my third year of growing dahlias and i have left them in the ground to over winter. I prefer the dinner plate plants and cover them with very large pots with the bottom removed and them put 8-10 inches of old soil on top. When i remove the covers i dig up the tubers which are enormous and on just one plant i can have 30+ cuttings. When planting out the small plants i cover them again with pots to keep out all light for about a week. This makes the roots grow very quickly as initial wilting is avoided.

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