Native to moist meadows and stream banks across Europe and Asia, Myosotis scorpioides is one of those plants that knows exactly where it wants to be. Given consistently wet or even standing water up to three inches deep, it spreads quietly by creeping rhizomes into dense, floriferous colonies — a reliable ground cover for the boggy margin that stumps most gardeners. The genus name comes from the Greek for mouse ear, a nod to the short pointed leaves; the species name honors the flower cymes that coil like a scorpion's tail before opening.

At ten to eighteen inches, it stays low enough to read as texture rather than structure, and those blue flowers are reliably attractive to bees through fall. It tolerates poor soil and heavy clay as long as moisture is constant, making it forgiving for water garden containers — plant in one-gallon pots submerged to three inches to keep spread in check. Mildew can appear in stagnant air but rarely causes lasting harm. In parts of the Midwest it has naturalized aggressively enough to earn noxious weed status, so a little oversight keeps it from overstaying its welcome.