Iresines are easy to take cuttings from, they root easily in water, ... but they will not survive the winter in a cold greenhouse.

Thanks for the advice Hywel, I hadn't thought of rooting the cuttings in water. I'll give it a try and if they root I'll keep them on the windowsill in the house over winter.

I think they'll be all right on a warm windowsill. That's where I keep mine and they last for years :o)
Good luck !