In 2012, I crossed a Daubenton Perennial Kale with a Purple Sprouting Broccoli that just happened to flower at the same time! The seed (collected from the Daubenton) were sown in Spring 2013. 12 plants were overwintered (in a cold cellar as they usually die outside here) and I planted them out in the garden in spring 2014. The resultant plants were a mix of short plants like Daubenton and tall plants like the broccoli! The dream here is a perennial purple sprouting kale…. They were overwintered again from 2014 to 2015 and a few of the taller plants are now producing broccolis. I will monitor the plants to see if any continue to perennialise.