This grower is fairly sure of this plant identification.
Miniature form for pot trough rockery etc. Grows to 10cm tall and 20cm spread. 7cm pot
Thorow-wax, Hare's ear
Bupleurum genus (Thorow-wax). This genus consists of annuals, perennials, evergreens and semi-evergreens shrubs. The leaves are alternate and simple, the flowers are star-shaped yellow to green and borne in umbels. They are grown for their foliage and flowers and will grow well in coastal areas. They are frost hardy and will need full sun and well drained soil. You can propagate by semi-ripe cuttings in the summer.
Grown for their foliage and flowers and grows well in coastal areas.