Bigroot geranium

Sun

Full sun to partial shade; tolerates deeper shade but flowers less. Give afternoon shade in hot climates.

Water

Water regularly during the first growing season. Established plants tolerate dry spells; water during prolonged drought if leaves wilt or brown.

Soil

Well-drained soil, including clay, loam, chalky or sandy soil. Tolerates a wide pH range and relatively poor soil, but dislikes persistent waterlogging.

Height

1-1.5 ft (0.3-0.45 m)

Spread

1.5-3 ft (0.45-0.9 m), gradually spreading farther through rhizomes

Flowers

Late spring to early summer; pink to magenta flowers held above the leaves. White-flowered cultivars are also available.

Foliage

Rounded, deeply lobed, softly hairy green leaves with a strong scent when rubbed. Leaves often turn red or bronze in autumn; foliage persists in mild winters but may die back in cold areas.

Growth

Moderate; forms broad, dense patches over several seasons.

Care needed

Low

• Water new plants deeply when the soil begins to dry during their first growing season.
• Keep the soil well drained; avoid low spots that stay wet through winter.
• Apply a thin layer of compost in spring if growth is weak; routine feeding is usually unnecessary.
• Remove encroaching rhizomes at bed edges before they spread into small neighbouring plants.
• Divide crowded patches in spring or early autumn, and water divisions until established.

Pruning. After flowering, remove spent flower stems and trim untidy foliage if needed; avoid cutting healthy evergreen foliage down unnecessarily. Remove winter-damaged leaves in early spring.

Early spring

Remove damaged leaves and check that spreading rhizomes remain within the intended area.

Spring

Plant or divide clumps, then water thoroughly and keep moist while they establish.

Late spring

Enjoy the flowers; remove any weeds before the foliage closes over them.

Early summer

Remove spent flower stems and lightly tidy any ragged foliage.

Summer

Check new plants during dry weather; water established patches only during prolonged drought.

Early autumn

Divide or reduce oversized patches while the soil is still warm and conditions are moist.

• Plant beneath deciduous trees and shrubs to create a leafy carpet in dry shade.
• Use along informal path edges, where the aromatic foliage can be appreciated without obstructing the path.
• Combine with spring bulbs to cover their fading leaves as the geranium fills out.
• Repeat broad patches beneath roses or mixed shrubs to soften bare stems and reduce weeding.
• Use on well-drained banks where spreading rhizomes can knit together into low cover.

Garden styles it suits: Woodland, Cottage garden, English country, Low-maintenance, Sensory garden and Wildlife garden.

Plant it with: Daffodils, Hellebores, Epimediums, Solomon's seal, Foxgloves and Shrub roses.

Wildlife: Flowers provide nectar and pollen for bees and other visiting insects. Dense foliage offers shelter for small garden animals; deer and rabbits often leave the aromatic leaves alone, although browsing is still possible.

• Root or crown rot in waterlogged soil: improve drainage or move plants to a raised, better-drained position.
• Leaf scorch or summer browning in hot, exposed sites: provide afternoon shade and water during prolonged drought.
• Occasional leaf spots: remove badly affected leaves, improve airflow and avoid wetting foliage when watering.
• Spreading into neighbouring plants: lift unwanted rhizomes and divide or trim the patch at its edges.

Not known to be toxic to people, cats, dogs or horses; no part is recognised as poisonous. It is not a food plant, and eating substantial amounts of foliage may cause stomach upset. Do not confuse it with pelargoniums, also commonly called geraniums, which have different toxicity risks.

• Cambridge geranium (Geranium × cantabrigiense)

  This hybrid has similar aromatic foliage and spreading rhizomes but usually makes a lower, more compact mat with smaller leaves and flowers.

• Dalmatian cranesbill (Geranium dalmaticum)

  Much lower and finer-textured, with smaller, glossier leaves and pale pink flowers; it forms a tight mat rather than a tall leafy patch.

• Bloody cranesbill (Geranium sanguineum)

  Has much more finely divided leaves and generally larger, open flowers. It lacks the broad, strongly aromatic leaves characteristic of bigroot geranium.

Geranium comes from the Greek word for crane, referring to the beak-shaped seed head, while macrorrhizum means large-rooted and refers to its thick rhizomes.

Propagation. Divide clumps in spring or early autumn, retaining roots and growing shoots on each piece. Rooted rhizome sections establish readily. Seed can be sown when ripe, but named cultivars should be divided to preserve their characteristics.

Accepted botanical name

Geranium macrorrhizum

Native range

Albania, Austria, Bulgaria, France, Greece, Italy, Romania, Turkey and Yugoslavia.

Measured

Average height 30 cm.

Sources: GBIF (CC BY 4.0) and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.