Geranium macrorrhizum
Common Name: cranesbill 
Type: Herbaceous perennial
Family: Geraniaceae
Native Range: Southern Europe, Turkey
Zone: 4 to 8
Height: 1.00 to 1.50 feet
Spread: 1.00 to 2.00 feet
Bloom Time: May to July
Bloom Description: Purple pink
Sun: Full sun to part shade
Water: Dry to medium
Maintenance: Low
Suggested Use: Ground Cover, Naturalize
Flower: Showy
Leaf: Good Fall
Attracts: Butterflies
Tolerate: Rabbit, Deer, Drought, Erosion, Dry Soil

Culture

Easily grown in average, dry to medium moisture, well-drained soil in full sun to part shade. Appreciates some afternoon shade in the St. Louis area. Tolerates full sun in cool summer areas. Tolerates drought due to thick rhizomes. Also tolerates hot and humid summers better than most other species of geranium. Plants of this species do not need to be cut back, sheared or otherwise trimmed after flowering. Removal of flowering stems is all that is usually necessary for maintaining attractive plant appearance. If foliage decline occurs in summer, individual leaves may be removed as they yellow. Plants will easily spread in the garden by rhizomes. Plants may also self seed but cultivars may not come true from seed. Clumps may be divided.

Noteworthy Characteristics

Geranium macrorrhizum, commonly called bigroot geranium, 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.

Problems

No serious insect or disease problems.

Uses

Popular ground cover. Border fronts, cottage gardens or wild gardens.