I was given a white an pink lupin last year in the summer, I planted them in rich potting compost, feed them every 2 weeks with Miracle Grow, had them in dappled sun most of the day and a few hours of full sun in the afternoon, I sprayed them pretty often sometimes once a week with powdery mildew treatment ( it comes back without regluar sparying). My tow were small when I got them and they grew to really nice sized plants that summer producing about 4-5 flower spikes each that summer.
I moved house that same year and put them in full all day sun and they struggled and wilted, so I planted them out at my new house in a dappled shade area. This year the white one is coming back healthy and strong already with a tuft of leaves waiting to burst out in spring. However the pink one sent up only one leaf shoot that looks like its struggling, I have a feeling this cold March may finish it off.
I did go to Homebase a few weeks back and there were some lupin seedings in the sale as they had wilted due to not being watered so I got about 30 large plugs for £9. I have since planted them in compost one plant per container and put them in a poly tunnel. I took them out just this Tuesday when the weather was warm and left them ou for the week they have recoved from their wilt and have formed strong tufts of leaves that have started bursting out some have one or two large leaves so I am hoping to have a garden full this summer. I have since put them back under the tunnel due to the Freezing weather.