I grow pentas here in TX. I was given some cuttings and got them rooted. I have the regular penta with fuchsia flowers and the variegated one with red flowers. I really enjoy them since they keep blooming right through summer.
My SIL started out with a small pot and now it is huge! Mine have gotten fairly big too. This is the 2 year for them.
Inthegarden- TX, Zone "9"