Perennial, spreading by seed and rooting of stems. It is said to have been on the ground at the entrance to the cave where Christ was laid to rest and when he stepped out onto it he blessed it for being soft. This gives the plant special significance and could relieve the pain of childbirth if placed under the right knee. Also women would hold a piece in their mouth when kissing a suitor to ensure the relationship would be long-lasting or drinkind an infusion would attract a partner. Faries were accused of spiriting people away so placing some over the door would keep them out.

It forms a dense mat close to the ground. The very fine, grass-like leaves can be mistaken for a moss. Very invasive and a problem in close cut lawns - raise the mower to allow the grass to outgrow it. Watch out for it on the surface compost of new plants (discard the top few centimetres before planting). Seed can be spread while mowing and carried on soles of shoes. Has been suggested as a non-grass lawn, but unless you want complete garden coverage, avoid.
Flowers from April to September, small bead-like buds. Four green sepals larger than the four white petals inside.
Height - up to 5 cm, but usually more squat.
Hand weed, regrowth from the roots is not a problem provided the growth point is removed, but it can be difficult to remove so with a large area it may be easier to slice off the surface. Small fragments can regrow. Remove at seedling stage if possible, but they are tiny like miniature tufts of grass, so tedious to remove in number. It's difficult to tell the maturity of the seeds and hoeing can disperse them. A weed burner should destroy most of the plants and the seed.

Weedkillers to use:-
Paraquat, Diquat kill seedlings on contact, but more mature plants will require a systemic like Glyphosate. It will probably take more than one application due to the presence of seed.
On paths a product containing a residual agent should prevent the seed from germinating for a while.
On lawns a selective herbicide ( singular, or a weed-and-feed type ) will require a few applications due to persistence of seed.

See also the monograph on Moss which is sometimes mistaken for Pearlwort.

Follow these links for further details on Weeds, Weed Removal and Weed Prevention.