Colt's-foot is a perennial which spreads by seeds, but mainly by creeping underground stems. The shallowly lobed leaves emerge in spring after the flowers have faded, on long purplish stalks which arise at ground level and can reach 30cm high. The mature leaves have white, felted undersides with toothed, black-tipped margins and the overall shape gives rise to the common name.
The first part of the scientific name is derived from the Latin tissis meaning cough and in unenlightened times the dried leaves were smoked to relieve coughs and asthma! More realisticly a juice or syrup made from the fresh leaves has been used for the same purpose. However, it contains some alkaloids which can be mildly toxic to the liver, so should only be used under the supervision of a qualified practitioner. Colt's-Foot water has been applied to ease the discomfort of piles, and an ointment was popular with the Ulster Scots to relieve swellings. The crushed leaves can be used to ease stings, insect bites or inflamed skin.
Flowering occurs from February to April; the single, yellow, rayed flowers are held on stout stems which are covered in overlapping purplish scales. Later downy seedheads develop.

It can be a problem to remove once estsblished; uproot as much of the underground growth as possible and repeat on any regrowth. Repeated close mowing will eradicate it so it not a problem in the lawn, but it will re-emerge from adjoining areas if it is not eradicated there.
Use a systemic or selective weedkiller to kill the underground parts.

See also Winter Heliotrope which has similar leaves and growth habit.

Nicholas Culpepper
(17th century astrologer-physician)
"The dry leaves are best for those who have thin rheums and distillations upon their lungs, causing a cough"
Rheums - watery or catarrhal discharge.