Herb Robert
Perennial & invasive weed
Herb Robert is a soft, low-growing geranium that often appears in cracks, shaded beds and sheltered corners. Its finely cut foliage and small pink flowers can be charming, but it seeds freely and rapidly fills bare soil. Fortunately, it is shallow-rooted and usually easy to remove when dealt with before its seed capsules ripen.
How to identify it
Plants generally grow 10-40 cm high, with branching, often reddish stems and soft, deeply divided leaves that have a ferny outline. Foliage frequently turns red in sun, cold or dry conditions, and has a strong scent when handled. Small five-petalled pink flowers, often with pale streaks, appear from spring into autumn. Long, beak-like seed capsules follow and flick seed away when dry. Roots are fine and shallow, without extensive runners.
Where it grows
Herb Robert grows in shade or part shade, especially at the foot of walls, beneath shrubs, in old mortar, paving gaps, woodland-style borders and disturbed soil. It can appear through much of the year in mild UK weather, with flowering and seeding continuing from spring into autumn. It exploits small pockets of bare ground remarkably quickly.
Why it is a problem
Although individual plants are easy to lift, they produce seed repeatedly and can form a busy carpet among young plants, pots and paving. Seedlings establish in tight spaces that are awkward to weed, then mature before they are noticed. In crowded borders, its foliage can shade small plants and make maintenance look untidy.
How to control it
Pull plants by hand while small, ideally after rain, taking the shallow roots with them. Use a hand fork around established clumps and hoe fresh seedlings in dry weather before flowers or seed capsules form. Collect pulled flowering plants rather than dropping them on bare soil. Mulch open borders to reduce germination, and check cracks, pot margins and wall bases regularly. Repeated early weeding prevents the seed bank from building up and is usually enough for control.
Commonly confused with
It resembles other cranesbills, especially dove's-foot cranesbill, but Herb Robert usually has softer, more ferny leaves, reddish stems and brighter pink flowers. Its strong scent and frequent red colouring are helpful clues. Young plants may also resemble cut-leaved geranium seedlings, which develop similar beak-like seed capsules.
Herb Robert: frequently asked questions
How do I identify herb robert?
Plants generally grow 10-40 cm high, with branching, often reddish stems and soft, deeply divided leaves that have a ferny outline.
How do I get rid of herb robert?
Pull plants by hand while small, ideally after rain, taking the shallow roots with them.
Where does herb robert grow?
Herb Robert grows in shade or part shade, especially at the foot of walls, beneath shrubs, in old mortar, paving gaps, woodland-style borders and disturbed soil.
General guidance for UK gardens and allotments, focused on prevention and non-chemical control. For a confirmed identification, the RHS or a local garden centre can help. Page updated 18 Sep 2026.