Everywhere but in the plant world, Jack Frost is a sprite-like character with roots in Viking lore. Quoting Wikipedia, in the U.S., “Jack Frost is a variant of Old Man Winter and is held responsible for frosty weather, for nipping the nose and toes in such weather…and leaving fernlike patterns on cold windows in winter.” It’s the latter description that accounts for naming a popular Brunnera macrophylla ‘Jack Frost’. Siberian bugloss, heartleaf brunnera, and false forget-me-not are common names for this perennial.
Growing 12 to 15 inches tall and spreading to about 20 inches, this multi-season plant has blue flowers—which look very much like forget-me-nots—in the spring and frosty-silver leaves with green veins through the rest of the growing season. ‘Jack Frost’ is hardy to USDA zones 3-8 and thrives in shade. (I have a friend who planted it in compost-enhanced soil in full sun with moisture and it’s almost gotten too big for her border. Hers appears a lot more robust than mine that are planted in full shade.) The Perennial Plant Association says that the rough leaf texture makes it less palatable to browsing deer, a big advantage if you live out in the country in the Northwest or in much of the rest of the country. The plant combines well with other shade perennials such as hostas, ferns and epimediums.