Dahlias in Containers

[SuntannedSwede]

I have just started some large dahlia tubers, and I'm trying to figure out where I should put them. My raised beds are only two feet wide and about 8 inches deep, not big enough for these monsters I thought.

I have several containers 15" deep and 24" across, would I be able to plant one tuber per container? I have been scouring the internet for hours but all the information out there seems to be for smaller cultivars. The varieties I bought will be 4' high and the blooms are 11" across or so. I have a sturdy support system but I want to make sure they have all the space they need for proper development.

Good plan? Or should I find some other way of planting them?

[Deborah]

I'd be interested in which dahlias you've chosen. A dear friend of mine was Edna Comstock, whose husband bred and named for her a very well known dahlia called the Edna C.

[SuntannedSwede]

I had to look that up, what a beautiful flower. I bought four tubers each of Cafe au Lait, Penhill Watermelon, and Walter Hardisty.

Do you think I should keep it at one tuber per container?

[RJGlew]

Originally Posted by SuntannedSwede

I had to look that up, what a beautiful flower. I bought four tubers each of Cafe au Lait, Penhill Watermelon, and Walter Hardisty.

Do you think I should keep it at one tuber per container?

Only Walter Hardisty is over 10" across (AA). It is a beautiful white - grew it for many years in a better climate than where I currently am. Penhill Watermelon is a great variety too. Enjoy.

Cafe au Liat - B - Informal Decorative
Penhill Watermelon - A - Semi-Cactus
Walter Hardisty - AA - Informal Decorative

[SuntannedSwede]

Good to know, thank you. Would you allow one tuber per container, or would it be acceptable to double up? Assuming heavy feedings of liquid fertilizers

[Deborah]

I don't know anything about dahlia culture. It's one of those "someday" things I still haven't done. I'd love to see pictures when yours are blooming.

[RJGlew]

Originally Posted by SuntannedSwede

Good to know, thank you. Would you allow one tuber per container, or would it be acceptable to double up? Assuming heavy feedings of liquid fertilizers

Recommended spacing for AA varieties is 18" so your call. They are heavy feeders so I work in a half handfull of granluar 6-12-12 or 10-10-10 when I plant them, and a second dressing of the same somewhere between mid-July & mid-August. Keep the fertilizer away from the stem to avoid burning the plant.

Where I live now I have a hard time flowering AAs (10"+) due to our short season but I always try a few - this year my AAs will be AC Darkhorse, Bonaventure, Clara Huston, Holland Festival, Kelvin Floodlight & Purple Taiheijo. I start the AAs & As indoors in pots (right about now) before planting them out in early/mid June. Typically the smaller the flowers, the earlier they bloom so choose your flower sizes a accordingly. I tend towards `B' (medium, 6"-8") here in Zone 3a since they always flower, unless decimated by hail.

[greenthumbomaha]

The dahlias I am familiar with would need to be lifted and stored in your growing zone if you want to replant them next season. I wonder if you could overwinter them in containers in your garage.

- Lisa

[RJGlew]

Originally Posted by greenthumbomaha

The dahlias I am familiar with would need to be lifted and stored in your growing zone if you want to replant them next season. I wonder if you could overwinter them in containers in your garage.

- Lisa

They all need to be lifted for winter storage in colder climates - Dahlias originated in Mexico, and any frost will immediately kill the foliage to the ground, and if your soil freezes, the tubers will die. I certainly can't overwinter them here in my garage (Zone 3a), but folks in better climates should be able to. I store mine in the coolest room in the basement, right on the floor. They need to be stored between 4 and 8 degress Celcius or else they will sprout.

[NewWestGardener]

I think you are fine for the first year anyways, as you only have a single tuber of each variety. Your pots should be big enough. You'll get an idea in the fall how many more tubers each plant developed and then the decision for next year would be piece of cake . Several tubers in one pot for more branches, or single ones in more pots. I like to plant several tubers of the same variety in one spot for a better show.

Hope it helps. Happy Gardening!

[PhilaGardener]

+1 on one per container. They will grow large and multiply. Next year you will be trying to find friends to give homes to all the splits. Almost floral zucchini!

[SuntannedSwede]

Thank you guys for the help- I have set aside enough pots for all of the tubers, only have 3 that are sprouting though.

Much appreciated

[KarenO]

they will need lots of water, fertilizer and support like a big tomato plant. three good stakes placed around them and then some string to hold the branching plant adding more string as they grow.they are very large plants and the blooms are heavy. I like growing them in pots but they take a fair bit of work. worth it for the gorgeous blooms.
KarenO

[SuntannedSwede]

Good to know Karen- I was wondering about how many stakes I would really need

[Deborah]

I'm looking forward to pictures! Of the plants and their blooms.