It is common in woods, hedges, gardens, and on waste ground, and can also be found on shingle beaches and limestone pavements.

Herb-robert is a small, usually biennial but sometimes annual or even short-lived perennial herb that typically grows to about 30 cm (1 ft) tall and broad, or sometimes up to about twice that size.

The flowering stems can arise vertically or sprawl along the ground, and some of them can turn into stolons by putting down roots at the nodes.

Flowering occurs from early spring to late autumn in northern Europe and plants remain green over winter.

The petals are from 8 to 14 mm long, purplish-pink with white stripes, and with the claw (stalk-like basal part) slightly shorter than the limb.

In Britain, in particular, it can be very difficult to separate herb-robert from little robin in coastal locations; various varieties and hybrids have been described.

The generic name comes from the Ancient Greek word for the plant, γεράνιον (géranion), which comes from γέρανος (géranos) 'crane' with the diminutive ending -ιον, "little crane".

Sell & Murrell,[2] for example, describe three subspecies in Britain: Geranium robertianum has generally been found to have a chromosome number of 2n = 64, although there has been a count of 2n = 32.

The two species have been found to hybridise on beaches in south-west Britain and Ireland to produce largely infertile offspring with a chromosome number 2n = 48.

[11][12] Its Ellenberg values in Britain are L=5, N=6, F=6, R=6 and S=0, which means that it typically grows in places with light shade, moist neutral soils with moderate fertility and no salinity.

However, it can occupy a wide range of habitats, including shingle beaches in full sun and grikes in limestone pavements.

It is also considered characteristic of E5.43 shady forest edges, F3.11 Central European thickets on moist soils, H2.6C Illyrian sub-Mediterranean screes, and G1.7A1212 Pannonic alkali steppe oak woods.

Some claim it is from St Rupert, who is also known as Saint Robert, because a German name for it is ruprechtskraut (another, more prosaic one is Stinkender Storchschnabel).

[19] In Britain there are dozens of other country names for herb-robert, some of which ("robin-in-the-hedge", "robin's-flower") make reference to the European robin because of the colour and the habitat.

Maud Grieve, for example, did not mention it at all in her influential herbal,[23] but there are other accounts of it being used in the folk medicine of several countries, including as a treatment for diarrhea, to improve functioning of the liver and gallbladder,[24] for toothache and nosebleeds,[25] and as a vulnerary (used for or useful in healing wounds).