Forming a large clump to 120 cm (47 in) tall, it has glowing reddish purple colored flowers with prominent dark centres, and divided leaves tinted red in Autumn.

[2] G. psilostemon has the UK’s hardiest rating, surviving temperatures as low as −20 °C (−4 °F).

[3] The Latin specific epithet psilostemon means "with smooth stamens".

[4] Like other geranium species, G. psilostemon is useful as underplanting for larger shrubs such as roses.

It has earned the Royal Horticultural Society's Award of Garden Merit.