The alpine or woodland forget-me-not (Myosotis alpestris) grows just about anywhere, and for that reason some folks class it as a weed. But I love it, both in the garden and the vase, where its pretty blue flowers last for an age. It grows very well in cooler areas, though it will also grow in warmer spots, in sun or shade. These plants self-sow readily (hence the tendency to call it a weed), though they’re easy to pull out as well.
Sow seeds now for a spring showing. Available from Kings Seeds.