Bought one - grew one free!

Just over 2 weeks ago I got some miniature Buddleia plants, one each pink, blue and white. As I was potting them up a small piece broke off one of them. Rather than throw it away, I stuck it in a little jug of water on the kitchen windowsill. Look at it now - all those roots have grown in just 17 days!  I am amazed - I have a reputation for killing all plants, but this may well survive - I will pot it up soon and see what happens.