Cephalaria radiata

Tall and airy, allowing other  perennailas to shine. The flowers are lovely too and long lasting.

The leaves are more divided, the plant is almost as tall as C. gigantea.  It is also tall and wispy...I just love this plant at the back of a border. Standing tall and gracefully open with masses of flower heads that are a little more open than the other species. At head height it has attractive foliage and masses of scabious-like flowers of pale creamy lemon. Fantastic for cutting. Will self sow quite a bit but easy to weed/edit out. Hardy and tough. 

Like most others, I have trouble telling the two giants apart. But these are from Jelitto so we can be sure. 

First image against ancient bricks: Acabashi, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons