| In mid and late summer, Eryngium x zabelii (Eryngium alpinum x Eryngium bourgatii) produces beautiful intense blue or violet flowers in rounded umbels, to 1 1/2 inches wide, with green tipped blue bracts. This is a clump-forming, semi-evergreen perennial with dark green, heart-shaped, basal leaves, 3 to 5 inches long, on blue stems. |