Tiny Tuesday: Flower Head

I don't think there's a theme for Tiny Tuesday this week but if there is, I missed it. Having got shrubs in one border and cleared out the others for bedding, this is the only thing in bloom in my garden until the peonies come out, which should be next week judging by the buds. No idea what it is but it's a clump-forming plant which is covered with these small flower heads.