Try just 1 in a pot that size.I wouldn't be afraid to use that soil,either.I've not kept 1 in a pot but grow them in the garden every year. Usually they will reseed..When it warms up they take off. I have to trim them to keep in bounds & this is just 1 by itself.
Rose Iowa

Mine wasn't really that much. It was thin. I'll try to look for a picture.

hey.. long time.. no time

i hope you arent comparing your result to say.. a zone which has an extra couple months in the growing season??

otherwise.. hyper fertilize it.. w/o killing it ...

ken

Hey Ken,

:D Long time....Been so busy at work...I didn't fertilize it last time. Also, I saw the dirt that I used last time today. It has tons of like grain skin. It doesn't really look like a dirt like what MiracleGro sells.

Neil

Ken has a good point. I plant them from seed here in early April and rarely see blooms until August. They simply take a long time to get big enough to bloom...but they are so worth the wait!

It's a really big plant. I am guessing that a pot is crowding the roots and limiting the plant from reaching its full potential. But maybe not. Try it again and see. There's very little to lose.