Garden flowers

Hardy geranium

GeraniumGeraniaceae
Also: Cranesbill, Geranium
AT A GLANCE
Part shade Water: average H7below −20 °C 30–60 cm tall · 40–60 cm wide In a pot: yes
Flowering · UK
Flowering · Northern Italy
Flowering · Central Italy
Flowering · Southern Italy and islands

Hardy geraniums are the plant to reach for when a border needs filling and nobody has time to garden. They cover ground, flower for months, grow in sun or half shade, and are almost never eaten by anything.

The one technique worth knowing is the mid-season shear: cut the whole plant back hard after the first flush, water it, and three weeks later it is a fresh green mound in flower again. Do not confuse them with pelargoniums, which is what garden centres label 'geraniums' on the bedding bench.

Care

Light

Most tolerate part shade well, a genuinely adaptable genus.

Water

Drought-tolerant once established.

Soil

Adaptable, moderately fertile, well-drained soil; tolerates poor soil once established.

Pruning

Shear back hard after the first flush of flowers in summer to encourage fresh foliage and a second flowering flush.

Feeding

Doesn't need feeding in any reasonable soil — a mulch of garden compost in spring is the whole regime. Fed generously it makes a mound of leaf that swamps its own flowers and then collapses open after rain.

Propagation

Division is the method: lift a clump as it starts into growth or after it has been cut back, pull or cut it into fist-sized pieces with roots and shoots, and replant straight away. Every piece takes.

Month by month

Months change with the climate: in southern Italy tomatoes go out two months earlier than in England.

  1. MarchDivide congested clumps. how ›
  2. AprilLight feed as growth resumes. how ›
  3. JuneShear back hard after the first flowering flush for fresh growth and repeat bloom. how ›

Months based on climate: UK. Your choice stays on this device.

  1. MarchDivide congested clumps. how ›
  2. AprilLight feed as growth resumes. how ›
  3. JuneShear back hard after the first flowering flush for fresh growth and repeat bloom. how ›

Months based on climate: Northern Italy. Your choice stays on this device.

  1. FebruaryDivide congested clumps. how ›
  2. MarchLight feed as growth resumes. how ›
  3. MayShear back hard after the first flowering flush for fresh growth and repeat bloom. how ›

Months based on climate: Central Italy. Your choice stays on this device.

  1. FebruaryDivide congested clumps. how ›
  2. MarchLight feed as growth resumes. how ›
  3. MayShear back hard after the first flowering flush for fresh growth and repeat bloom. how ›

Months based on climate: Southern Italy and islands. Your choice stays on this device.

Common problems

Powdery mildewfull sheet ›

How to spot it. In dry summers.

What to do. Shear back and water to refresh growth.

Sawfly larvaefull sheet ›

How to spot it. Holes in leaves.

What to do. Remove by hand if noticed early.

Slugs

How to spot it. On young growth.

What to do. Protect emerging shoots.

Popular varieties

Geranium ‘Ann Folkard’AGM45–60 cm × 1–1.5 m · June–SeptemberJune–SeptemberMay–SeptemberMay–September
Geranium ‘Biokovo’AGM20–30 cm × 60–90 cm · May–JuneMay–JuneApril–MayApril–May
Geranium ‘Johnson's Blue’AGM45–60 cm × 60–75 cm · June–JulyJune–JulyMay–JulyMay–July
Geranium ‘Max Frei’AGM25–30 cm × 40–45 cm · June–AugustJune–AugustMay–AugustMay–August
Geranium ‘Mrs Kendall Clark’AGM60–75 cm × 60 cm · May–JulyMay–JulyApril–JulyApril–July
Geranium ‘Rozanne’AGM45–60 cm × 90 cm–1.2 m · June–OctoberJune–OctoberMay–OctoberMay–October

Questions

Hardy geranium: is it hardy?

H7: Fully hardy anywhere in the UK. It survives below −20 °C.

Can it grow in a pot?

Happier in open ground long-term.

Hardy geranium: when do you prune it?

Shear back hard after the first flush of flowers in summer to encourage fresh foliage and a second flowering flush. In the calendar for UK, pruning falls in June.

Hardy geranium: when does it flower?

In the climate of UK it flowers in May–August.

When do you feed it?

Doesn't need feeding in any reasonable soil — a mulch of garden compost in spring is the whole regime. Fed generously it makes a mound of leaf that swamps its own flowers and then collapses open after rain.