Bigroot geranium (Geranium macrorrhizum) — care & requirements

In short

Grows in sun and shade, including difficult, dry shade under trees.
Forms a dense, close carpet that effectively suppresses weeds.
The aromatic leaves are semi-evergreen and turn red in autumn.
Very resistant to drought, frost and neglect — practically maintenance-free.
Blooms in May and June, attracting bees and bumblebees.

Botanical data

Family: Geraniaceae (Geraniaceae)
Height: 0.25–0.4 m
Width: 0.4–0.6 m
Habit: Creeping
Growth rate: Fast
Position: Full sun, Partial shade, Shade
Soil: Humus-rich, Loamy, Sandy, Chalky
pH reaction: pH 6–7.8
Moisture: Dry, Moderate
Bloom: May–June
Hardiness: USDA 4a–8b
Propagation: By division, From cuttings, By runners, From seed

Characteristics

It spreads by means of thick, fleshy rhizomes creeping over the soil surface, from which palmately lobed, resinously scented leaves grow. In summer the foliage is fresh green, and in autumn and winter it colours rusty and red, as the plant usually does not shed all its leaves. In May and June, small, pink to purple flowers with long, protruding stamens hover above the clump, along with the characteristic beak-shaped fruit typical of cranesbills.

Growing and care

Watering

One of the few groundcover perennials that cope well in dry shade under trees. Once established, very drought-resistant — watering is needed mainly in the first season and during long heatwaves.

In summer every ~12 days · drought tolerance: High

Fertilizing

An undemanding plant — a thin layer of compost in spring is enough; fertilising is not necessary.

optionally once a season, in spring · kompost w niewielkiej ilości

Planting

Tolerates almost any well-drained soil, including poor and stony ones. Over large areas, plant at a spacing of about 30–40 cm so that it quickly closes into a dense carpet.

Timing: April–May or September · spacing 30–40 cm

Pruning

After flowering the clump can be lightly trimmed to make it denser and refresh it; in spring, remove damaged or discoloured leaves.

Timing: After flowering and, if needed, in early spring. · Caution: Pruning is not necessary — the perennial maintains its close habit excellently on its own.

Companion plants

Good companions

Siebold's plantain lilyPractical observation

A classic duo for shade — the geranium densely fills the space between the hosta clumps and suppresses weeds while the hosta's leaves are still unfurling.

American alumrootPractical observation

Both perennials value partial shade and form a striking foliage composition; the decorative leaves of the coral bells contrast with the aromatic foliage of the geranium.

Heart-leaved bergeniaPractical observation

Two hardy, evergreen groundcover perennials with similar requirements — together they make a dense, low edging for borders and banks.

Bad companions

Small, slow-growing perennials and bulbsPractical observation

The geranium's dense, fast-spreading carpet can smother delicate, slow-growing neighbours by taking their light and space.

The evidence level indicates whether the relationship is backed by research, observation, or gardening tradition.

Diseases and pests

Slugs and snails

Slugs and shelled snails that feed at night and after rain. Symptoms: irregular holes in the leaves and young seedlings eaten off completely, silvery slime trails on leaves and soil. The greatest damage occurs in damp, shaded spots — particularly on lettuce, strawberries and hostas. The most damaging in gardens are the slugs (which lack an external shell): the Spanish slug (Arion vulgaris, formerly described as A. lusitanicus) and the grey field slug (Deroceras reticulatum). The leopard slug (Limax maximus) can be morphologically similar to them, but it feeds mainly on decaying organic matter and fungi and may even prey on other slugs, so it is of little importance as a pest of living plants. Shelled forms — grove snails (Cepaea) or the protected Roman snail (Helix pomatia) — usually cause less damage. The body is soft, elongated and permanently covered in slime; on the head there are two pairs of retractable tentacles — the longer upper pair bears the eyes, the shorter lower pair serves a tactile and olfactory function. Slugs and snails are hermaphrodites: they lay spherical, transparent or pearly eggs in clusters, hidden in damp soil, under stones and in leaf litter. A single Spanish slug can lay several hundred eggs; both eggs and young slugs overwinter, and feeding lasts from spring to late autumn, intensifying on warm, damp nights. The damage has smooth edges and often appears in the middle of the leaf blade, not only from the margin; seedlings and transplants are sometimes eaten down to bare soil, and on strawberries and ripening vegetables the slugs gnaw hollows into the fruit. The decisive diagnostic sign is the dried, silvery glistening slime trail — no insect leaves one.

Toxicity

For whom	Level	Notes
Humans	None	The plant is considered non-toxic; in sensitive people, contact with the aromatic leaves may rarely irritate the skin. The essential oils of the leaves are extracted in perfumery.
Dogs	None	—
Cats	None	—

History and origin

A species of the southern European mountains, cultivated in gardens for centuries; its aromatic leaves were the source of an oil (known as zdravetz) used in perfumery, especially in the Balkans. In modern horticulture it gained fame as a reliable groundcover for places where few other perennials cope.

Uses

Ideal for planting banks, underplanting beneath trees and shrubs, border edges and dry, shaded places where it is to suppress weeds. It also performs well in naturalistic and rock gardens and as undemanding greenery in parks.

Trivia

Crushed leaves give off an intense, resinous-spicy scent that effectively deters deer and rabbits.
In the Balkans the oil of this plant, known as zdravetz, is sometimes an ingredient of perfumes.

Frequently asked questions

Will bigroot geranium cope in dry shade under trees?

Yes — this is one of its greatest strengths. It is among the few groundcover perennials that grow well in dry shade, where they compete with tree roots. Once established, it forms a dense, self-sufficient carpet there.

Is bigroot geranium evergreen?

It is semi-evergreen — in mild winters it keeps most of its aromatic leaves, which additionally turn red and rusty. Frost-damaged leaves are easily removed in early spring, and the plant regenerates quickly.

How do you propagate bigroot geranium?

The simplest way is by dividing the clump or cutting off fragments of the creeping rhizome with roots in spring or early autumn. The sections root quickly, which is why the plant is very easy to multiply over larger areas.

Sources

RHS — Geranium macrorrhizumInstitution / botanical garden
Plants of the World Online (POWO) — Geranium macrorrhizumDatabase (GBIF, POWO…)

Edited by:Redakcja Atlas-Flora. Updated: 7/19/2026.

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Bigroot geranium

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