Geranium macrorrhizum, known as bigroot geranium, Bulgarian geranium, and rock crane's-bill, is a species of hardy flowering herbaceous perennial plant in the genus Geranium, family Geraniaceae. It is native to the South east Alps and the Balkans.
Geranium macrorrhizum is a rhizomatous semi-evergreen perennial that typically grows to 12" tall but spreads to 24" wide to form a thick, weed-resistant ground cover. Deeply lobed and rounded, grayish-green leaves (4-8" long) have 5-7 lobes, with each lobe having 3 to 5 notches at the tip. Leaves are strongly aromatic when crushed. Leaves acquire attractive red tones in autumn. Long-lasting purple-pink flowers (to 1" wide) with inflated dark red calyces bloom in umbel-like clusters above the foliage in late spring to early summer, often with some sporadic rebloom occurring throughout summer. Genus name comes from the Greek word geranos meaning crane in reference to the fruit which purportedly resembles the head and beak of a crane. Specific epithet and bigroot common name are in obvious reference to the thick roots of this plant.