A worldwide community photographing and learning about wildlife
Oxalis acetosella
Actually the Oxalis genus is widespread in a variety of climates, with greatest diversity in the tropics.
We have a very similar species--Oxalis oregana. Ireland and the Oregon coast must have similar climate & soils I guess. It can be called a "shamrock", but I understand that shamrock usually refers to clover.
Order: Oxalidales
Family: Oxalidaceae
Genus: Oxalis
Edible and can be used as a spice in cooking or just added in salads.