With bright blue forget-me-not flowers in spring and silver marbled leaves all summer, B. ‘Jack Frost’ is a joy. The species Brunnera macrophylla is a native to north eastern Turkey, the Caucasus and Georgia to western Siberia in forests and open grassy slopes, forming a compact clump with bright blue forget-me-not flowers on wispy branchlets in early spring, followed by coarse heart shaped leaves that remain to make good ground cover all summer. The species and some cultivars will grow in full sun in cooler summer regions. B. ‘Jack Frost’ is a relatively new introduction that arose as a mutation or sport in the micropropagation unit at Walters Gardens in Michigan, and has already found a place as one of my favourite gardenworthy plants: hardy, reliable and undeniably showy. ‘Jack Frost’ makes a fine and long spring display of light twinkling blue flowers, but it is the silver-veined and marbled leaves that follow that make it a valuable plant for garden and container.
As its origins suggest, ‘Jack Frost’ is very hardy; however, leaves can be easily scorched in hotter climates in full sun or where dry root conditions exist, so if in any doubt plant in full or part shade where roots are moist. Old flowers are best removed as soon as flowering is finished, and if the foliage becomes damaged during summer cut back, water and mulch for another show of brighter, cleaner leaves, although these may be smaller. This plant offers so many opportunities for plant combinations throughout its season from spring to autumn: try it with the black-leaved Ophiopogon planiscapus ‘Nigrescens’. Propagation is by division, but damaged roots may regrow with green leaves so care should be taken. ‘Jack Frost’ and other selections will seed freely on moist soils if flowers are not removed, but will vary from the parent. 45–60 cm (1½–2 ft.) × 60 cm (2 ft.) F spring, Z 3–8
Brunnera macrophylla ‘Hadspen Cream’ was raised by English plantsman Eric Smith and is a robust alternative to B. ‘Jack Frost’, with mid-green heart-shaped leaves edged irregularly with creamy yellow. It is free flowering and makes good, dense ground cover once established in part shade. 30–45 cm (1–1½ ft.) × 45–60cm (1½–2 ft.), F spring, Z 3–8.