Scarlet Flax flowers are spectacular with their glossy, deep scarlet red, and they bloom in profusion and are best admired if planted densely. Linum Rubrum Scarlet Flax prefers full sun in well-drained soils. It often re-seeds and will be back the next spring. Scarlet Flax wild flower is a hardy annual, native to northern Africa and Southern Europe. Once established this variety can tolerate immense heat and extremely dry conditions though it will need watering at the height of summer.