Flower description / bloom time
Jack Frost has China-blue sprays of flowers in April and May for 3 to 4 weeks with no repeat flowering later in the season. However, flowers are not Jack Frost’s main feature — flowers only received a ‘good’ rating over the evaluation period.
Foliage interest / color and texture
Medium green, heart-shaped leaves are heavily marbled in silver-white. The variegated foliage boldly stands out as a ‘color’ throughout the growing season in the shaded garden. Even in a drought year  foliage did not have browned edges.
Habit and growth rate observations
The mounded habit of the foliage takes about a year from planting to achieve a height of 12 inches with the flowers adding an additional 9 inches. The plants reached a width of 18 to 24 inches in a 2- to 3-year period.
Site preference / soil and light
Jack Frost grows best in slightly moist, well draining soil in part shade or shade. It showed great drought tolerance in 2005 while growing under Norway maples.
Successes and possible drawbacks—how to overcome them
Showy foliar variegation stands out in shaded gardens from April to November. For appearance the plant looks best if the spent flower stems are removed. It was also thought that seedlings might revert to the species but on at least one site the seedlings remained true to type. There was only one report of minor slug damage.
Notes from growers / retailers
Foliage seems to be very consistent and nicer than other variegated Brunnera macrophylla cultivars. As recommended for garden planting, Jack Frost requires excellent drainage to avoid root diseases. By mid-June the plant develops nice foliage, is moderately rooted and in bloom. Jack Frost can be potted bare root in mid-April and grown outdoors under 30% shade cloth. One grower generally sells about 75% and over winters the remaining 25% under micro foam and white plastic right on the ground. Another grower recommended growing plants in a ‘squat pot’ (wider than tall). Brunnera is also salt-sensitive so growers should periodically drench soils to remove excess salt.
Some suggested companion plants include Athyrium filix-femina ‘Frizelliae’, Carex ‘Ice Dance’, and Impatiens ‘Lipstick’.
Parting SHOT —the overall evaluation results were Excellent ****
Brunnera macrophylla ‘Jack Frost’ is an easy-care perennial for brightening a darker area of the garden – it is the foliage of Jack Frost that makes this plant a standout! For most of the evaluators this plant performed well in dry, shaded conditions filling a much-needed position in the garden. Jack Frost received the highest overall rating of Excellent ****.