This grower is fairly sure of this plant identification.
Tuberous rooted variety with yellow flowers. Not hardy.
Oxalis genus (Sorrel). These are tuberous, rhizomatous or fibrous-rooted perennials and semi-evergreen sub-shrubs. The leaves are divided into heart-shaped leaflets. The funnel-shaped flowers are pink, white or yellow; they are carried in an umbel-like cluster on slender stalks.
They are fully hardy to frost tender, min 5C, and will need full sun or semi-shade with well drained soil.
Grown for their colourful flowers (which in bud are rolled like an umbrella), and their often attractive leaves.