I’m not positive which Allium this is, but I am going to go out a limb and say it is an ornamental onion ‘Allium Senescens’ Thanks to Joe the on the garden web forum ‘Name that plant’ for the identification. The plant stands about 2 – 2 1/2 feet tall. The flower heads are about 2 – 2 1/2 inches across the middle. Many seeds were tightly packed in the flower head. It’s too bad I missed it in bloom. Oh well, this summer I will get to see it’s beauty. The image of the flower is from Wikipedia and attributes go to Meneerke bloem for the use of the photo.