Siberian bugloss (Brunnera macrophylla 'Jack Frost')
Achieve stunning woodland charm with Brunnera macrophylla 'Jack Frost' (Siberian bugloss), featuring silvery foliage and blue flowers.
Complete Plant Information
Overview
Brunnera macrophylla ‘Jack Frost’ is highly prized for its breathtaking foliage, making it a standout choice for shaded garden areas. This herbaceous perennial, commonly known as Siberian bugloss, forms dense clumps of heart-shaped leaves heavily splashed with silvery-white, accented by dark green veins. The spring display is completed by delicate, bright blue, forget-me-not-like flowers that hover above the striking leaf mound.
This plant offers low maintenance and high impact, slowly spreading via rhizomes to create a reliable and attractive ground cover. While beloved for its leaves, the ephemeral spring blooms provide an excellent early-season color contrast in woodland settings. Selecting Brunnera macrophylla ‘Jack Frost’ ensures seasonal interest long after the flowers fade.
For gardeners seeking reliable performance in dappled light, the Siberian bugloss is an excellent perennial foundation plant. Its preference for cool, moist conditions means careful placement is key, particularly avoiding intense afternoon sun which can scorch the unique leaves. Ensure proper soil preparation to maximize the visual appeal of ‘Jack Frost’.
Fast Facts
- Plant Family: Boraginaceae
- Plant Type: Herbaceous perennial
- Hardiness Zones: USDA Zones 3-8
- Size at Maturity:
- Height: 1-1.5 ft
- Spread: 1-1.5 ft
- Bloom Time: April to May
- Bloom Description: Blue
- Sun Exposure: Part shade
- Water Needs: Medium
- Maintenance Level: Low
How to Grow
The ideal time to establish Brunnera macrophylla ‘Jack Frost’ is during the spring or fall when temperatures are moderate. Plant in average, medium-moisture, well-drained soil. While it tolerates some dryness once established, this Siberian bugloss thrives best in organically rich soils that remain consistently moist, mimicking its native woodland environment.
Watering should be regular to maintain that medium moisture level, especially during dry spells. Avoid letting the soil dry out completely, as this can stress the plant and potentially damage the foliage. Fertilizing is generally unnecessary if the soil is rich in organic matter; excessive feeding can sometimes lead to reduced variegation quality in the leaves.
Regarding pruning, maintenance is minimal. A quick cleanup of any tattered or damaged leaves in early spring is usually sufficient. Be aware that plants prefer cooler summers; in the hot, humid conditions of the Deep South (Zones 7-9), the foliage of Brunnera macrophylla ‘Jack Frost’ may scorch, so location selection is crucial for long-term success.
Landscape Uses
Brunnera macrophylla ‘Jack Frost’ is perfectly suited for use as a textured ground cover, mass planting, or for edging woodland borders where its silvered leaves catch the low light beautifully. It performs excellently in groups or masses, suppressing weeds while creating a clean foundation layer beneath taller shrubs or trees. The elegant foliage makes it a strong specimen plant when placed in containers or mixed with spring bulbs.
In woodland gardens, pair the Siberian bugloss with plants that share similar light and moisture needs, such as Hostas, Ferns, or early spring bloomers like bleeding hearts. The blue flowers of Brunnera macrophylla ‘Jack Frost’ contrast beautifully with white or yellow-flowering companions. Allow it to naturalize in moist, shady areas to enhance the informal, natural aesthetic.
Standout Features
Flower Qualities
- Showy
Noteworthy Characteristics
Brunnera macrophylla, commonly called Siberian bugloss, is a rhizomatous, clump-forming, herbaceous perennial native to forested, mountain slopes in northeastern Turkey and the Caucasus. It is primarily grown in shady areas for its attractive heart-shaped, dark green, basal foliage. Small, blue, forget-me-not-like flowers with white centers bloom in airy, branched racemes rising well above the foliage on slender stems to 18” tall in spring. The cultivar ‘Jack Frost’ leaves are a distinctive silvery white with green primary and secondary veins and a thin green rim around the leaf edges.
Tolerances
- Rabbit
Potential Problems
Brunnera macrophylla ‘Jack Frost’ is generally resilient, exhibiting no serious insect or disease problems when grown in appropriate conditions. The primary occasional visitors are slugs and snails, which can chew holes in the soft foliage, especially right after emergence in spring. To manage pests, use bait pellets applied strategically around the base of the plants or encourage natural predators like ground beetles. Rabbits typically avoid eating this Siberian bugloss due to the texture or slight sap compounds within the leaves.
Frequently Asked Questions
What hardiness zones is Siberian bugloss suitable for?
Brunnera macrophylla ‘Jack Frost’ is hardy and reliably grown in USDA Zones 3 through 8.
How large does Brunnera macrophylla ‘Jack Frost’ grow?
This perennial typically reaches a mature height between 1 and 1.5 feet, with a similar spread of 1 to 1.5 feet.
What sun exposure does Brunnera macrophylla ‘Jack Frost’ need?
The best environment for this plant is Part shade; intense, direct afternoon sun can cause the attractive silver foliage to scorch.
When does Siberian bugloss bloom?
The dainty blue flowers appear relatively early in the season, usually spanning from April through May.
Conclusion
The unique, silver-etched foliage of Brunnera macrophylla ‘Jack Frost’ provides essential contrast and brightness in deep shade plantings, making the Siberian bugloss an indispensable perennial. Its low maintenance requirements and reliability cement its value in any cool, moist garden border or woodland area. Before planting, verify your garden site matches the required part shade and medium soil moisture to ensure your ‘Jack Frost’ displays its best characteristics all season long.
Companion Planting
Selecting companions for Brunnera macrophylla ‘Jack Frost’ should focus on other shade-lovers that share the need for consistently moist, rich soil. Consider pairing it with various Heuchera (Coral Bells) cultivars, whose leaf shapes and colors complement the large heart-shaped leaves of the Siberian bugloss. Hellebores (Lenten Rose) are excellent companions, offering very early bloom before the Brunnera fully leafs out, followed by the long-lasting foliage of Astilbe toward mid-summer.
For textural diversity, incorporate fine-leaved plants such as Japanese Forest Grass (Hakonechloa macra) or native ferns against the broad leaves of the Brunnera. This combination prevents the shade garden from looking too monolithic, ensuring that the silver tones of Brunnera macrophylla ‘Jack Frost’ remain vibrant against rich, dark greens and finer textures throughout the growing season.
Design Ideas for Deep Shade
The striking variegation of ‘Jack Frost’ makes it an ideal plant for illuminating otherwise dim corners of the garden where dark shadows tend to collect. Use it as a living mulch beneath deciduous trees, allowing the spring flowers to appear just as the tree canopy begins to thicken. When planting, use groups of three or five plants closely together to create an immediate impact, rather than spacing them individually for gradual naturalizing.
For containers, utilize the Brunnera as a ‘thriller’ or ‘filler’ element, pairing it with trailing ivy or colorful impatiens that enjoy the same cool, moist conditions. The consistent quality of the Brunnera macrophylla ‘Jack Frost’ foliage means that even when flowers are absent, this plant remains a focal point. Ensure containers have excellent drainage to prevent root rot, despite the plant’s moisture needs.
