I see you haven't gotten a response, probably because I think harlequins are the bedding dahlias, and most dahlia addicts grow the three ft to seven feet varieties in the ground.

I've never seen six-packs of dahlias in the store, so I had been watching to see if anyone would respond, as well.

Please don't take a no-answer as ignoring, but as a collective "I'm not sure..."

Cheers!
CC

Well I'm a new dahlia lover. Last year I grew a bargain bulb from Walmart and it was the most beautiful red and white bloom. So, about the 6 packs. I bought a container from Lowes last summer. It was about a 20 inch pot. I would estimate that there were 3-4 plants. It filled the container nicely. The six packs won't get very tall. Flowers are not huge but they are pretty.

The Harlequins are a bedding dahlia, getting about a foot tall (or less).

I've grown single plants in 2-gallon pots, where they did reasonably well. So if you want to plant three of them in one pot, I'd go with a 7- or 10-gallon pot.

One-gallon pots are too small in my experience - the roots get too hot.

I like the Harlequins, and I save my favorites. They make tubers just like real dahlias!

I saw little six packs of bedding dahlias at one of the small nursery set ups around here for the first time this year.

I grew some from seed last year and again this year, and was wondering why they were not popular with the growers. I didnt grow Harlequins, and I grew them in the ground, but the two types I have tried ended up being 12-18" tall and wide. They bloomed well all summer.