A stem cutting from a dark red/purple penstemon that I planted out last year is now flowering, but nothing like the parent plant. I can't remember if it flowered last year, but if so, it would have been as I expected. The flowers are a kind of mid blue nearest the stem, going to pink at the edge of the petals, with dark pink stripes on the white-ish inside. They are pretty but I like my penstemons to be strong colours! Though the plant is very vigorous, there are (so far) not many flowers.
Any idea what's going on?