I love this time of year when the Autumn gentians start to flower.
(http://img.photobucket.com/albums/v172/Berghill/AASeptember/gentian.jpg)
This is a form of the Wilow gentian.
Lovely colour. Are these fairly hardy and suitable for an allotment?
Tough as old boot leather, they are about 18 inches to 2 feet tall and if you want to see them in all their glory go to Sizergh Castle near Grange over Sands. If happy they will self seed all over too. I've got my fingers crossed it will be happy enough to spread.