Linum narbonense (Linaceae). Perennial flax or blue flax, is a flowering plant native to Europe. One of the finest blue flowered plants. A profusion of luminous ultra-marine blue flowers. Sowing : Sow in trays, pots, etc of good seed compost in a propagator or warm place to maintain an optimum temperature of 20-25C. Sowing Depth: Surface sow using peat/sand mix seed compost. Locality : Ex Hort. Date of harvest : October 2015.