Geranium × cantabrigiense 'St. Ola'
Common Name: hardy geranium
Type: Herbaceous perennial
Family: Geraniaceae
Zone: 4 to 8
Height: 1.00 to 1.50 feet
Spread: 1.50 to 2.00 feet
Bloom Time: June to July
Bloom Description: White
Sun: Full sun to part shade
Water: Medium
Maintenance: Low
Suggested Use: Ground Cover
Flower: Showy
Attracts: Butterflies
Tolerate: Rabbit, Deer

Culture

Easily grown in average, medium moisture, well-drained soil in full sun to part shade. Tolerates some drought, but prefers and spreads best in moist, humusy soils with good drainage. Deadheading is tedious for larger plantings and unnecessary. Side stems may be removed at any time to control spread. Foliage may decline after flowering in hot summer climates, at which point it may be lightly sheared back and shaped to revitalize.

Noteworthy Characteristics

Geranium is a large genus containing in excess of 300 species of mostly herbaceous perennials and sub-shrubs which grow in a variety of habitats, primarily in cool temperate regions throughout the world. Plants typically have palmately-lobed often aromatic leaves and 5-petaled flowers in colors ranging from white to pink to red to blue to purple, mostly appearing in cymes, umbels or panicles.

Geranium x cantabrigiense is a sterile hybrid geranium developed in 1974 by Dr. Helen Kiefer of the Cambridge University Botanic Garden in Cambridge, England, by crossing G. macrorrhizum (female parent) and G. dalmaticum (male parent). Plants spread by trailing stems to form a foliage carpet to 8-12” tall spreading to 18” wide or more. Foliage consists of aromatic, deeply-cut, 7-lobed, glossy light green, palmate, semi-evergreen leaves (to 3 1/2” wide). Long-persisting, white to pink sterile flowers (to 1” wide) bloom from late spring into early/mid-summer with a sporadic rebloom sometimes continuing to fall. Cultivars of this hybrid expand the color range of the flowers to include shades of red and purple. Plants grow well in rock gardens or as ground covers.

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.

Hybrid name of cantabrigiense comes from the Latin word Cantabrigia meaning of or pertaining to Cambridge, England.

‘St. Ola’ is a hybrid member of the cantabrigiense group. Parents are G. macrorrhizum ‘Album’ crossed with G. dalmaticum ‘Album’. It features bright white flowers on plants growing to 15” tall while spreading to 24” wide. It was named after the parish of St. Ola located in Mainland, Orkney, Scotland, which was, at that time when the cultivar was developed, the home of the breeder, Alan Bremner. In comparison to other geraniums in the x cantabrigiense group, the flowers of the within plant are slightly larger (to 1 1/2” across) and are pure white with a small pink center blush, lacking significant pink overtones. It is very similar in appearance to Geranium x cantabrigiense ‘Biokovo’.

Problems

No serious insect or disease problems. Some susceptibility to leaf spots and rusts.

Garden Uses

Rock gardens or border fronts. Mass for ground cover. Edging. Containers.