Self seeding seedlings

Try saying that when you're drunk! I have two Buddleia bushes in my back garden - neither of which I planted - they just sort of appeared one summer about three or four years ago. They seem to have self-seeded from bushes in a neighbour's garden three houses down. Looking at this dead seed head, you can understand how and why this happens. This is just part of one flower head from one stem on the Buddleia and it contains hundreds of seed pods (mostly empty now). I'm sure the birds will eat some of them, but others would have been carried and spread in the wind, thus ensuring future generations of flowers... and more importantly providing sustenance to our bees and butterflies - can't wait until they flower again this summer.