Lungwort or Bethlehem Sage

(Boraginaceae - Borage Family)

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• Form
  • miniature herbaceous perennial
  • maturing at about 1' tall by 1.5' wide
  • radiating clump growth habit

• Culture
  • partial shade to full shade
  • prefers an evenly moist, deep, rich, and well-drained topsoil high in organic matter, in partial shade to full shade; adaptable to partial sun (some leaf scorch and constant wilting) or deep shade (less vigor and fewer flowers), but not at all tolerant of poorly drained soils
  • propagated primarily by crown division in the Spring or Autumn, but also lightly self-sowing if not deadheaded after flowering
  • Borage Family, with crown rot and root rot being the primary diseases that affect plants that are improperly planted in wet sites or poorly drained clay soils
  • commonly available in container form, with quite a few cultivars
  • good soil drainage is critical for the long-term life of the crown and roots of this perennial, and yet the foliage will wilt during the periodic droughts of Summer if moisture is not evenly provided

• Foliage
  • elliptical variegated leaves are medium- to dark green, pubescent to bristly on both upper and lower surfaces, with silver speckles or blotches that yield a striking mottled to marbled appearance
  • foliage emerges early and radiates from the central crown (ranging from 4" to 12" long, depending upon cultivar), and becomes alternate and much smaller along the flowering stalks
  • the foliage remains viable (although faded) after many frosts and light freezes, and while prostrate in late Autumn and Winter, may be semi-evergreen in southern climates

• Flowers
  • pink, violet, or blue buds open to slightly nodding blue flowers on stalked inflorescences in late April and early May, opening before the basal foliage has fully expanded
  • other cultivars of this species may have violet or white inflorescences, while other species and hybrids may have purple, blue, violet, red, orange, salmon, or white inflorescences

• Fruits
  • ornamentally inconspicuous, but lightly self-sowing if the soil is exposed below the plant

• Twigs
  • not applicable

• Trunk
  • not applicable

• ID Summary
  • this perennial for shady areas has elliptical, radiating, basal green foliage that is pubescent to bristly, and speckled or blotched with silver variegation, with Spring inflorescences that are slightly nodding and often transition from pink buds to cobalt-blue flowers

• Function
  • shady spots in beds at foundations, entranceways, and underneath trees, used in group or mass plantings as a specimen perennial, or as a non-traditional variegated groundcover

• Texture
  • medium texture when in foliage
  • thick density when in foliage or flower

• Assets
  • strikingly variegated foliage of silver speckles or blotches on a green background
  • lovely nodding cobalt-blue or white flowers in Spring, often with pink buds beforehand
  • performs optimally in partial shade conditions, but also performs very well in full shade to deep shade conditions, where few other perennials or groundcovers thrive

• Liabilities
  • crown rot and root rot occur in poorly drained soils
  • powdery mildew may occur on the foliage when the plant is sited in permanently moist and/or poor air circulation areas (although the mildew is often unnoticed among the silver variegation)

• Habitat
  • zones 3 to 8
  • native to Europe

• Alternates
  • perennials or groundcovers with striking silver-, cream-, or white-variegated foliage, especially those for partially to fully shaded sites (Arum italicum 'Pictum', Hosta 'Patriot', Lamiastrum galeobdolon 'Variegatum', Lamium maculatum 'White Nancy', Polemonium caeruleum 'Brize D'Anjou', etc.)

• Variants
  • primarily selected based upon floral color, foliage shape, and especially for degree of foliage variegation (newly emerging cultivars with this lattermost trait often have great names, including 'Berries and Cream', 'British Sterling', 'Silver Streamers', and 'Spilled Milk'); a few of the well-established cultivars and several species are noted below:
    • Pulmonaria longifolia 'Roy Davidson' - this species has much longer leaves with acuminate apices; this cultivar has dark green foliage with silver variegation and violet-blue to cobalt blue flowers
    • Pulmonaria rubra 'Redstart' - solid green leaves that develop a subtle speckling in Autumn, with red-salmon flowers in Spring
    • Pulmonaria saccharata 'Excalibur' - nearly solid silver leaves with irregular green margins
    • Pulmonaria saccharata 'Mrs. Moon' - long the standard cultivar of Lungworts, its leaves are much shorter (about 4" long) and more rounded than all other cultivars, and having well-separated, round, silver speckles on a medium-green foliage background; also very prone to self-sowing and will form a dense mat of low groundcover in naturalized or neglected areas
    • Pulmonaria saccharata 'Sissinghurst White' - white flowers provide a great foil for the silver-variegated foliage

• Translation
  • Pulmonaria is derived from the Latin word for "lung", and refers to times past when plants that resembled human organs were used to treat those body parts; in this case, the speckled leaves of Lungwort (resembling diseased lungs) were used as a raw material to treat various afflictions of the pulmonary organs of humans and domesticated animals.
  • saccharata translates roughly as "sprinkled with sugar" and refers again to the variegated, spotty foliage.

• Purpose
  • Lungwort is a marble-foliaged perennial or non-traditional groundcover that is a good substitute for variegated Hostas in those shady sites with moist, well-drained, organically-enriched soils.

• Summary
  • Pulmonaria saccharata is known as a perennial with excellent blue flowers and speckled silvery-green foliage, best sited in partial shade to full shade in moist organic soils, and used either as a specimen perennial or en masse as a focal point mounding groundcover.