Cambridge cranesbill

Cambridge cranesbill: how do you recognise it?

Habit

Low, dense mat 15–25 cm high that spreads to 60 cm and more by creeping stems.

Leaves

Rounded, palmately lobed and slightly glossy; semi-evergreen, partly red in autumn.

Flower

Flat, five-petalled flowers 2–2.5 cm across with prominent stamens, in clusters just above the foliage.

Colour

Pink, lilac-pink or white flushed pink, depending on the cultivar.

Scent

The leaves smell spicy and slightly sweet when crushed.

Fruit

It rarely sets seed, so it hardly self-seeds.

Flowering: May–July · Plants: March–April and September–October · Pruning: March and July

Why grow it?

• One of the best ground covers: dense, low and largely evergreen.
• Weeks of flowers in May–July, sometimes with a few more if you cut it back.
• The leaves give off a spicy scent when you touch them.
• Tough and undemanding: copes with some drought, shade and poor soil.
• Bees love to visit the flowers.
• In autumn some of the leaves turn red and orange.

Cambridge cranesbill: where does it grow best?

• Sun or partial shade; also under shrubs and trees that let some light through.
• Any free-draining soil: sand, loam or clay, acid to chalky.
• Dry to normal: once established it tolerates drought, but not soil that stays wet for long.
• Plant 30–40 cm apart for a closed carpet, ideal at the front of a border.

Light

Sun and partial shade

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Dry or normal

Size

0.25 m tall, 0.6 m wide

Hardiness

Hardy (to -30 °C)

Goes well with

• Roses: A dense, low underplanting that keeps weeds down.
• Lady’s mantle: Yellow-green flower sprays beside the pink flowers, at the same front edge.
• Hosta: Large leaves beside the fine, rounded foliage in partial shade.
• Daffodil: Flowers earlier; the cranesbill leaves later hide the dying daffodil foliage.
• Catmint: Blue flowers in the same sun and dry soil.

Cambridge cranesbill: when and how to plant it?

Plant in March–April and September–October.

1. Plant in March–April or in September–October.
2. Loosen the soil and mix in some compost; on heavy soil, add some coarse sand too.
3. Set the plant at the same depth as in the pot and firm the soil.
4. Space plants 30–40 cm apart; allow 6–9 plants per m².
5. Water straight away and in dry spells for the first few months.
6. Mulch between the plants with compost or wood chips until the carpet has closed.

Care

Water

Only in dry spells in the first year; rarely needed after that.

Feeding

A thin layer of compost in spring is enough.

Deadheading

Cut off the flower stems after flowering for a tidy carpet and a few later flowers.

Tidying

In March, remove brown, damaged leaves; leave the green ones.

Division

Every 4–5 years, when the centre goes bare.

Tip: Use it to hide dying bulb foliage: plant daffodils or ornamental onions in the carpet, and the green cranesbill leaves will neatly cover their yellowing leaves.

Cambridge cranesbill: when to prune it?

Pruning months: March and July.

When: After flowering, in July, and a light tidy in March.

How:

• In July, cut off the spent flower stems just above the leaves.
• If the carpet has become untidy, shear it back to 5–10 cm with a hedge trimmer: it soon regrows.
• In March, cut away brown or damaged winter leaves; the green ones can stay.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In March–April or in September: dig rooted pieces from the edge and replant them at once.

Cuttings

From April to August: cut pieces of the creeping stems with a few nodes and insert them in moist cutting compost. They root easily.

Cambridge cranesbill: how does it get through the winter?

Hardy to −30 °C.

• Hardy to about −30 °C: no protection is needed in Belgium.
• In mild winters the leaves stay largely green; in hard winters some discolour or wither, but the plant shoots again in spring.
• In a pot or trough: keep it sheltered and make sure the compost does not stay wet in winter.

Diseases and pests

• Bare centre: Old plants go bare in the middle. Divide them and replant the young pieces from the edge.
• Wet feet: In heavy, wet soil it rots in winter. Improve drainage with coarse sand.
• Slugs: They sometimes nibble young leaves in spring, but rarely do much damage. Pick them off in the evening.
• Weeds in a young planting: Until the carpet closes, weeds grow in between. Hand-weed and mulch between the plants.

Through the year

• March: Clear away brown leaves. Plant and divide.
• April: Plant. Add compost.
• May: Flowering begins.
• June: Full flower.
• July: Last flowers. Cut off flower stems, or shear the whole plant back. Take cuttings.
• August: Water young plants in dry weather.
• September: Plant and divide.
• October: Plant. Autumn colour in the leaves.
• November: The leaves stay largely green.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• The cultivar ‘Biokovo’ was found in the wild in the Biokovo mountains in Croatia, where both parents grow together.
• It sets almost no seed, so it does not self-seed like many other cranesbills.
• In Bulgaria a fragrant oil is extracted from the leaves of one of its parents, Geranium macrorrhizum; this hybrid has partly inherited that scent.