Dahlia not blooming, just tiny pink flowers
I've had a Dahlia in a pot on my apartment patio for 3 years now. It grew back once and had no problems last year and hs grown back this year even bigger but seems to not be blooming.
It got ridiculously taller than usual it's about 5 feet or more growing out of the planter. The problem is that it only has many stalks with tiny pink flowers instead of the large pink/yellow blooms it usually has.
I've never had to do much but water it in the past and I know very little about gardening. I've uploaded a photo of it so you can get an idea.
What can I do to fix it?
Here is a link that might be useful: