Bigroot cranesbill

Bigroot cranesbill: how do you recognise it?

Habit

Dense, creeping mat 30–40 cm tall, spreading to 60 cm or more per plant.

Leaves

Soft, sticky-hairy, palmately cut into five to seven lobes; semi-evergreen, partly red in autumn.

Flowers

Pink, white or magenta, with an inflated calyx and long, protruding stamens; May to July.

Scent

The leaves smell strong and spicy when crushed or brushed against.

Roots

Thick, fleshy rhizomes that creep along and just below the surface.

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

Why grow it?

• One of the best ground covers for dry shade under trees and shrubs, where little else will grow.
• The leaves smell spicy and aromatic and largely persist through mild winters.
• Red to orange autumn colour on some of the leaves.
• Flowers from May to July and attracts bees and bumblebees.
• Smothers weeds and needs almost no work after the first year.

Bigroot cranesbill: where does it grow best?

• Sun, partial shade or shade: it grows anywhere, even in dry shade.
• Any garden soil, from poor sand to heavy clay, acid to chalky.
• Dry to moist soil; it copes with drought far better than with waterlogging.
• Plant 30–40 cm apart for ground cover that closes quickly.

Light

Sun, partial shade and shade

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Dry or normal

Size

0.4 m tall, 0.6 m wide

Hardiness

Hardy (to -35 °C)

Goes well with

• Ferns: Together they quickly fill a dry, shady corner under trees.
• Lenten rose: Flowers in winter and early spring above the soft green.
• Hosta: Big leaves as a contrast to the finely cut foliage.
• Snowdrop: Pushes through the mat in February; then the leaves take over.
• Barrenwort: Another tough ground cover for dry shade, with dainty spring flowers.

Bigroot cranesbill: when and how to plant it?

Plant in March–April and September–October.

1. Plant in March–April or September–October.
2. Loosen the soil and, under trees, work in some compost to give the young plant a good start.
3. Set the plant at the same depth as in the pot; the rhizome may sit right at the surface.
4. Space plants 30–40 cm apart, or 5–8 per m² for quick ground cover.
5. Water well straight away and weekly in dry spells during the first year.
6. Spread a thin layer of leaf mould between the plants until the carpet has closed.

Care

Watering

Only in dry spells during the first year. After that it copes even in dry shade.

Feeding

Not needed. On very poor soil a little compost in March is enough.

Weeding

Weed between the young plants in the first year; after that the dense mat keeps weeds out by itself.

Deadheading

Cut off the spent flower stems in July for a neater look.

Keeping in check

If the mat gets too big, slice off a piece at the edge with a spade.

Tip: Plant it under trees and shrubs where grass gives up: water faithfully in dry spells during the first year, and after that it forms an indestructible, scented carpet that gives weeds no chance.

Bigroot cranesbill: when to prune it?

Pruning months: March and July.

When: Little needed. After flowering in July you can cut off the flower stems, and in March remove old, withered leaves.

How:

• After flowering, cut the spent stems off just above the leaves.
• In March, remove brown and damaged leaves so the new foliage comes through nicely.
• If the mat has become bare and leggy, cut it back hard in spring: it soon regrows.
• Wear gloves if you like: the scent of the leaves lingers on your hands for a long time.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

Very easy in March–April or September–October. Lift pieces with roots and a few leaf rosettes and replant them straight away.

Rhizome pieces

Loose pieces of rhizome with a leaf rosette root easily if you lay them on moist soil and press them in lightly.

Bigroot cranesbill: how does it get through the winter?

Hardy to −35 °C.

• Fully hardy, to about −35 °C: no protection is needed in Belgium.
• Some of the leaves remain in winter; in hard winters more of them drop, but the plant regrows normally in spring.
• In a pot or trough it copes well with frost; just make sure the water drains away freely.

Diseases and pests

• Spreading too much: The mat can swamp smaller plants. Slice off the edges in spring or autumn.
• Long, bare rhizomes: Older mats go bare in the middle. Cut back, or divide and replant.
• Drought in young plants: In the first year young plants can dry out under trees. Water weekly until they are well rooted.
• Slugs: They usually leave the scented leaves alone; only young shoots are sometimes nibbled.

Through the year

• March: Remove old, withered leaves. Give a little compost on poor soil.
• April: Plant or divide. Water young plants in dry spells.
• May: Flowering begins. Bees and bumblebees on the flowers.
• June: Full bloom.
• July: Cut off the spent flower stems.
• August: A quiet green carpet. Water young plants in dry spells.
• September: Plant or divide. Trim back mats that have grown too big.
• October: Red and orange autumn colour on some of the leaves.
• December: Semi-evergreen leaves keep the ground covered.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• In Bulgaria the plant is called zdravets, from the word for health. A fragrant oil used in perfumes is extracted from its leaves.
• The Latin name macrorrhizum means ‘with a large root’, after the thick rhizomes.
• The calyx of the flower is noticeably swollen, which sets it apart from most other cranesbills.