Geranium 'Johnson's Blue' (Johnson's Blue Cranesbill) — Mound-forming or spreading

Overview

Geranium 'Johnson's Blue' is a mound-forming or spreading perennial in the genus Geranium, part of the Geraniaceae family, with deciduous or semi-evergreen; rounded, palmately lobed, often aromatic foliage. Geranium 'Johnson's Blue' grows best in full sun to partial shade, and tolerates most soils and acid and neutral or alkaline pH. Its UK hardiness is rated H5–H7. Suggested uses include borders, rock gardens, ground cover, cottage gardens and pollinator gardens.

About

Geranium 'Johnson's Blue' is a perennial in the Geraniaceae with a mound-forming or spreading habit and rounded, palmately lobed leaves that are often aromatic. It flowers from June to September. The plant tolerates full sun to partial shade and will grow in almost any reasonable soil provided it is well drained. It suits exposed or sheltered positions across most UK gardens.

About the genus

Geranium is a genus of 422 species of annual, biennial, and perennial plants that are commonly known as geraniums, hardy geraniums, or cranesbills. They are found throughout the temperate regions of the world and the mountains of the tropics, with the greatest diversity in the eastern part of the Mediterranean region.

Wikipedia contributors, "Geranium", CC BY-SA 4.0 — Geranium

In the garden

Geranium 'Johnson's Blue' is a perennial geranium (family Geraniaceae) with a mound-forming or spreading habit and rounded, palmately lobed foliage that is often aromatic. It flowers from June to September, providing a sustained display through summer into early autumn. Sunlight needs are flexible: place it in full sun where soils stay cool, or in partial shade where summers are hot. It will establish in almost any reasonable soil — loam, chalk, sand or clay — and tolerates acid, neutral and alkaline pH so long as the site is well drained but not parched. Aspect can be any and the plant copes with exposed or sheltered situations. With a UK hardiness range of H5–H7, Geranium 'Johnson's Blue' is suitable for most gardens across the country; for reference its USDA hardiness range is 4–9. Use it in mixed borders to soften edges, as a ground cover between taller herbaceous plants, in rock gardens where it can creep between stones, or within cottage and pollinator plantings where its summer flowers are an asset. The combination of aromatic, palmately lobed leaves and a spreading habit makes it effective where a sustained, informal ground cover or summer-flowering understorey is needed.

Growing conditions

Best soil and position for Geranium

Sunlight: Full sun to partial shade
Soil type: Almost any reasonable soil — loam, chalk, sand or clay
Soil pH: Acid, neutral or alkaline
Soil moisture: Well drained but not parched
Aspect: Any
Exposure: Exposed or sheltered
UK hardiness: H5–H7

Plant details

Geranium 'Johnson's Blue' size, habit and characteristics

Plant type: Perennial
Habit: Mound-forming or spreading
Foliage: Deciduous or semi-evergreen; rounded, palmately lobed, often aromatic
Suggested uses: Borders, rock gardens, ground cover, cottage gardens, pollinator gardens

Care notes

Pruning and caring for Geranium 'Johnson's Blue'

Cultivation: Among the least demanding of perennials, asking only for reasonable drainage and an open position. Shear the whole plant back hard after the first flush and water it in; most kinds then produce fresh foliage and a second showing by late summer.
Pruning: Cut back to a low framework after the first flowering to renew the foliage and prompt repeat bloom. Tidy any remaining growth in late autumn or early spring.
Propagation: Divide in spring or autumn. Many species self-seed freely, and basal cuttings suit cultivars that resent disturbance.
Pest resistance: Largely untroubled, though vine weevil grubs attack the roots of container plants and sawfly larvae occasionally strip leaves.
Disease resistance: Powdery mildew and rust may appear on congested plants in a dry summer; shearing back usually resolves both.

Frequently asked questions

How do I grow Geranium 'Johnson's Blue'?

Among the least demanding of perennials, asking only for reasonable drainage and an open position. Shear the whole plant back hard after the first flush and water it in; most kinds then produce fresh foliage and a second showing by late summer.

Where is the best place to plant Geranium 'Johnson's Blue'?

Geranium 'Johnson's Blue' prefers full sun to partial shade. It suits exposed or sheltered positions.

What soil does Geranium 'Johnson's Blue' need?

Geranium 'Johnson's Blue' is adaptable and grows happily in most soil types, including almost any reasonable soil — loam, chalk and sand or clay. It prefers acid and neutral or alkaline soil. Aim for soil that stays well drained but not parched.

How do I prune Geranium 'Johnson's Blue'?

Cut back to a low framework after the first flowering to renew the foliage and prompt repeat bloom. Tidy any remaining growth in late autumn or early spring.