Petrorhagia saxifraga

Common Name: petrorhagia 
Type: Herbaceous perennial
Family: Caryophyllaceae
Native Range: Southern and central Europe
Zone: 5 to 7
Height: 0.50 to 1.00 feet
Spread: 0.75 to 1.50 feet
Bloom Time: May to August
Bloom Description: Pink
Sun: Full sun
Water: Medium
Maintenance: Low
Suggested Use: Ground Cover, Naturalize
Flower: Showy
Tolerate: Shallow-Rocky Soil

Culture

Winter hardy to USDA Zones 5 (possibly Zone 4) to 7 where it is best grown in medium moisture, well-drained soils in full sun. Performs well in rocky or sandy soils. Tolerates poor soils. Likes cool summer climates. Shallow root systems dry out quickly and appreciate a mulch to help retain soil moisture. Aggressively self-seeds in the landscape.

Noteworthy Characteristics

Petrorhagia saxifrage, commonly called tunic flower, coat flower, tunic saxifrage or pink saxifrage, is a spreading, mat-forming, grass-like perennial of the pink family. It is native to rocky, sandy, limy soils in the Pyrenees, southern to central Europe and Turkey. It has been introduced into North America where it has naturalized over time, primarily into fields, meadows and disturbed soils in Quebec, Ontario and the eastern and central U.S. north of USDA Zone 8. It is noted for producing a spreading foliage mat of short, narrow, grass-like, linear, pointed green leaves rising to only 4” tall but spreading over time to as much as 18” wide. Thin, wiry flower stems rise in spring above the foliage mat to 8-12” tall. Stems are topped by small dianthus-like, 5-petaled white flowers (to 1/2” wide) which bloom from spring into summer in loose clusters or solitary. Spring flowers are white, but summer flowers usually have pinkish tones. When flowering stops, plants may be cut back to encourage an additional bloom that may last into fall.

Formerly known as Tunica saxifrage, Dianthus saxifrage, and Dianthus filiformis.

Genus name comes from the Greek petros meaning rock and rhagas meaning narrow opening or fissure in reference to this plant’s ability to live in the cracks of walls.

Specific epithet literally means stone-breaker (from Latin saxum meaning rock and frangere meaning to break) in reference to this plant’s ability to live in rock crevices.

Problems

No serious insect or disease problems.

Garden Uses

Rock gardens. Cascade over walls. Raised beds. Ground cover for large areas. Border fronts. Path edger.