I grow my poker plants in containers, just because I do not plant anything on the ground..everything in containers.
When I got them as seedlings, I saw they got thick roots, so very rhizomatous.
I used to have Kniphofia Hirsuta Fire Dance, not sure if it is always short growing, since I planted it in a container, and my garden only gets part sun. But it was shorter than my other Kniphofia. Unfortunately it died after blooming..not even sure if it was over or underwatering..
These were photos last May 2012:
My other Kniphofia, Kniphofia sarmentosa is a tall grower and blooms during winter time to early spring. It is growing okay in my garden. I cut the wilted flowers and stalks, but I do not get a rebloom same season, it will do it next season again. This year after bloom time, I tied up the leaves, they looked unruly, then I even cut them very short. Now it is back growing new leaves, after I have been watering them a bit more due to the recent heat wave
Photos during its bloom early this year.
I have one other kniphofia, called Kniphofia caulescens..this one I do not know what it looks like..has never bloomed...just never ending leaves..
So I would think since your kniphofia is planted in ground, it will have very deep thick roots.
