Pulmonaria saccharata, Bethlehem lungwort, is a rhizomatous herbaceous perennial native to France and Italy. It is grown primarily for its lance-shaped leaves patterned with white or silver spots and for its early spring color - pink buds that open to violet-blue - at a time when little else in the shade garden is active. Plants spread to roughly 24 inches wide, making them effective ground cover beneath deciduous trees and shrubs.
It performs best in dappled to deep shade with consistently moist, humus-rich soil and tolerates pH 5.5–7.0. By midsummer the foliage often looks tired or develops powdery mildew; cutting the entire plant to the ground at that point prompts a flush of fresh, clean leaves that carry into fall. A 2–3 inch layer of leaf-mold mulch helps retain moisture and stabilize root temperatures. The plant is reliably cold-hardy to zone 3a without special protection.
The common name derives from the doctrine of signatures: the spotted leaves were likened to diseased lung tissue, and the plant carries a long history of use for respiratory complaints. Young leaves contain mucilage, silicic acid, tannins, and allantoin. Traditional preparations targeted coughs and bronchitis, and the allantoin content supports topical use in wound care. Young leaves of Pulmonaria species have also been cooked and eaten as potherbs in parts of Europe.
Powdery mildew
White or grey powdery coating on leaves - usually starting on older growth in humid conditions or when nights cool.
Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.
Fungal leaf spot
Brown or purplish spots on the leaves, often ringed with a yellow halo, that spread and merge in warm, humid, or wet weather; heavily spotted leaves yellow and drop early.
Pick off spotted leaves and clear fallen debris to remove overwintering spores. Improve air circulation by thinning, and water at the base so foliage dries quickly. If it persists, apply a copper- or sulfur-based fungicide at the first sign.