a huge mullein
I shook some mullein seed from a garden rather special to me some five years ago. I had some flower 2 years ago, but I believe they are biennial, and none last year. 2 years ago they grew about 5 feet tall from a rosette about 9 inches across. This year I have one flowering about 2.5 feet tall and a number of plants 9 inches across, but then a whopper like this one and another whopper on the way. If they are mullein how have they become huge? This one is about 3 1/2 feet across. It doesn't seem to be invasive and the plants I got two years ago were easy to move, but does this plant become invasive with its seeds?