I had this for many years in my Manchester Allotment. In spring 2020 I thought it had not survived the winter. I dug over the bed it was in and realised there was some roots of it still there. I potted this up just in case.
I bought a new one just in case.
Low and behold the original one sprouted well and I found space for this too. Now I have two separate plants.
It flowers reliably all summer and keeps a compact habit. A staple for a yellow border.
I moved it again in July 2020, swapping it with my Tradescantia.