Planning a dahlia garden part 2: design your plot

Hello there! I hope you are enjoying the light and the longer days of May. Here in Holland, we had a cold and dry start to spring. Not ideal growing conditions. It wasn’t all bad, though, the daffodils and tulips lasted a lot longer than normal. But now that the Ice Saints have gone, it is time to start hardening off your seedlings and plant out any potted up dahlias.

Warning: this post is all about dahlias and includes lists, facts and figures. Lots of words and no pretty pictures! I hope some of you find this interesting but if you are not growing dahlias yourself, you may find it boring. That’s okay! I am a little bit obsessed with creating the perfect dahlia garden, but I understand if you don’t share the same passion.

Ice Saints

The Ice Saints are four Catholic saints; St. Mamertus, St. Pancras, St. Servatius and St. Boniface. Their name days fall on the days of May 11, May 12, May 13 and May 14. According to folk wisdom, these are the dates of the last night frost of the spring. After these days, frost risk decreases sharply and at the end of May, temperatures below zero will be exceptional.

The Ice Saints are well known in Holland and other European countries. If you live in another part of the world, you can find out the date of your last spring frost on the internet.

When to plant dahlias in the garden

As you all know, dahlias are cold sensitive and should not be planted before the frosts are over. But you don’t have to wait until all danger of frost has passed.

I planted my dahlia tubers on April 12. The average temperature in April was 8,5°C (47,3°F). After April 12^th, we had 5 nights of frost, 4 in April, 1 in May. The lowest temperature was -3,4°C (25,9°F). Just to give you an impression what our climate is like.

Because the tubers are in the ground they are protected from the frost by the (warmer) soil. Of course, they won’t grow fast because temperatures are still low, but they will grow. This year, it took three weeks for the first shoots to appear.

Potting up dahlias

Lots of people pot up dahlias in March or April just to get a head start on their dahlias. By starting them indoors weeks before you would normally plant them in the garden, expecting this will get their dahlias blooming earlier.

I have never potted up dahlias before. First of all, because I am a bit of a lazy gardener. Filling pots with soil, planting the tubers, looking after them, and finally transplanting them into the garden, it’s just more work.

Secondly, because I don’t have a greenhouse or a cold frame. I don’t have anywhere to grow the potted tubers.

But this year I thought it would be a fun experiment to pot up a few tubers just to see if there is a huge difference in flowering time. I ordered several new tubers and potted up three of the new ones in mid-March. I used small pots because I was going to plant them in the dahlia garden anyway. They didn’t need lots of soil and nutrients; they just needed to get started.

I put them on the terrace, close to the house where it’s warmer. As you can see they survived the few nights of frost and are doing fine. Some of the tubers planted straight into the ground are about the same height, some haven’t come up yet. We’ll see!

Choosing dahlias

Last year I wrote a blog post about planning a dahlia garden. When choosing your dahlias it’s important to consider shapes, sizes, colours and height. If you are growing dahlias as cut flowers you will want flowers of different size and form. There are many flower forms, including the decorative, the cactus, the anemone, the ball and pompon, the peony, and the collarette dahlias. You will find examples of these forms in this blog post. More information on dahlia classification here.

I was very happy with last year’s selection and this year I just added a few varieties. I ordered Linda’s Baby and Labyrinth which I spotted at the dahlia show garden last year. And I finally found a collarette dahlia!

This year’s dahlia selection is:

• Ace Summer Sunset – decorative
• Bellelaine – cactus
• Black Jack – cactus
• Blue Bayou – anemone
• Boom boom white – ball
• Burlesca – pompon
• Café au Lait – decorative
• Classic Poème – peony
• Cornel – ball
• Cornel Brons – ball
• Floorinoor – anemone
• Labyrinth – decorative
• Linda’s baby – ball
• Lucky number – decorative
• Maarn – ball
• Platinum Blonde – anemone
• Preference – cactus
• Shooting Star – cactus
• Totally tangerine – anemone
• Twyning’s White Chocolate – collarette
• Waltzing Mathilda – other
• Zundert Mystery Fox – ball

Designing your plot

If you have been following this blog for a while, you know I have an allotment plot dedicated to dahlias. Even though I am growing dahlias just for cutting, I do want the plot to look pretty. I want my dahlias to look good together, not only in the vase but on my plot as well.

My plot is 20 m² (215 sq ft), approximately 4 x 5 m. (14 x 16 ft). At the allotment, we plant tubers 50 cm. (20 inches) apart. First, I divide the plot into 4 flower beds with paths between beds. I can fit in 2 rows of 9 tubers per bed.

Then the fun part begins. I like to colour coordinate the flower beds and can get a little carried away trying to create the perfect dahlia garden. I make several drafts before deciding on my final design.

This design goes into my garden notebook. I use it when planting the tubers. I don’t need any name tags, I know exactly which tuber is planted where.

All dahlias are planted on the allotment and about half of them have come up.

It will be a while before flowers appear, and of course, I will keep you posted. Make sure to subscribe to my blog to get updates delivered right to your inbox

Congratulations on reading till the end, you are a true fan and I thank you for that 😉