Lungwort (Pulmonaria 'Cotton Cool')
Pulmonaria 'Cotton Cool' Lungwort is prized for striking silver foliage and spring blooms, ideal for tough, shady spots.
Scroll down to discover growing tips, care requirements, companion plants, and more
Complete Plant Information
Overview
Pulmonaria ‘Cotton Cool’ is a magnificent herbaceous perennial, known commonly as Lungwort, that truly excels in challenging, shaded locations. This variety stands out due to its highly ornamental, mounding foliage, featuring deep silver leaves heavily splashed with white blotching. While valued for its flowers, the strong visual impact of the leaves provides season-long interest, making it a garden cornerstone where other plants struggle.
This Lungwort variety is valued for its low maintenance requirements and its ability to form dense masses, serving as an excellent choice for ground cover duties beneath mature trees. It offers charming spring color as its funnel-shaped flowers transition beautifully from pink buds to mature blue blossoms, often appearing simultaneously. Gardeners looking for reliable performance in deep shade will find Pulmonaria ‘Cotton Cool’ to be an indispensable addition.
Fast Facts
- Plant Family: Boraginaceae
- Plant Type: Herbaceous perennial
- Hardiness Zones: USDA Zones 4-9
- Size at Maturity:
- Height: 0.75-1 ft
- Spread: 1-1.5 ft
- Bloom Time: April
- Bloom Description: Blue
- Sun Exposure: Part shade to full shade
- Water Needs: Medium
- Maintenance Level: Low
How to Grow
Plant Pulmonaria ‘Cotton Cool’ in the spring or fall, ideally during cooler weather to help it establish new roots. This Lungwort thrives in average, medium moisture, well-drained soils that are rich in organic matter and humus. Ensure the planting site is consistently moist; these plants absolutely must not be allowed to dry out, especially during summer heat periods.
Maintenance for Pulmonaria ‘Cotton Cool’ is generally quite low. While they tolerate light morning sun, afternoon shade is critical, as foliage can scorch or depreciate in intense, hot summer weather. If soils dry out in peak heat, the plant may briefly go dormant, though good moisture management prevents this. Remove spent flower stems immediately after the intense bloom period concludes in spring.
Slowly spreading by creeping roots, Pulmonaria ‘Cotton Cool’ can become crowded over time. To maintain vigor and manage size, divide clumps during the fall months. Due to its evergreen or semi-evergreen nature in milder climates, the attractive leaves may provide valuable winter color, reducing the need for heavy cleanup until early spring.
Landscape Uses
The primary strength of the Lungwort, especially the striking Pulmonaria ‘Cotton Cool’, lies in its utility within shady borders and woodland settings. It works wonderfully when massed together to create a cohesive carpet of patterned foliage, making it perfect for use as a ground cover or naturalizing in dappled light areas. Its spreading habit means it effectively suppresses weeds once established.
For design purposes, use this perennial as an edging plant tucked along shaded pathways to draw attention to the foliage texture. Its relatively short stature (under 1 foot) makes it an excellent mid-to-front-of-border plant near larger shade-lovers like Hostas or large ferns. The emerging spring flowers provide early color contrast against the cool silver leaves before the main summer garden awakens.
Standout Features
Flower Qualities
- Showy
Noteworthy Characteristics
Pulmonaria is a genus of about 17 species of deciduous or evergreen herbaceous perennials from Europe and Asia. Lungworts are shade plants that, like many of the hostas, are often valued more for their attractive foliage than for their spring flowers.Gen-us name comes from the Latin pulmo meaning lung, in reference to the supposed resemblance of the blotched/spotted leaves to a diseased lung. ‘Cotton Cool’ is a mounding variety that features silver leaves with white blotching and blue flowers, typically forming a clump up to 12” tall with silvery, ovate leaves. Drooping clusters of funnel-shaped flowers emerge pink and mature to beautiful blue, presenting a mixed color palette during its spring bloom.
Tolerances
- Deer
- Heavy Shade
- Black Walnut
Potential Problems
Pulmonaria ‘Cotton Cool’ generally avoids serious pest and disease issues, though slugs and snails may occasionally target the leaves in damp conditions. The most significant cultural threat is related to moisture stress; allowing the soil to dry out, especially when combined with excessive heat or sun, can lead to leaf scorching and potential powdery mildew development. Fortunately, the ‘Cotton Cool’ cultivar is noted for having good resistance to powdery mildew, provided its requirement for consistently moist soil is met. Prevent issues by ensuring good air circulation and avoiding overhead watering in the late afternoon.
Frequently Asked Questions
What hardiness zones is Lungwort suitable for?
Pulmonaria ‘Cotton Cool’ Lungwort is reliably hardy in USDA Zones 4 through 9, offering wide adaptability across many temperate regions.
How large does Pulmonaria ‘Cotton Cool’ grow?
This herbaceous perennial generally reaches a height between 0.75 and 1 foot tall, spreading slowly to widths between 1 and 1.5 feet wide at maturity.
What sun exposure does Lungwort need?
This variety performs best when situated in part shade to full shade conditions, requiring protection from intense afternoon sun to prevent foliage scorch.
When does Pulmonaria ‘Cotton Cool’ bloom?
This Lungwort displays its signature blooms in April, featuring flowers that mature from pink to a lovely blue hue.
Conclusion
Pulmonaria ‘Cotton Cool’ is highly valuable in the landscape for its exceptional, silver-patterned foliage that brightens the darkest corners of the garden. As a low-maintenance Lungwort, it delivers reliable seasonal structure and early spring color. Ensure you plant Pulmonaria ‘Cotton Cool’ where soil moisture is consistent, and enjoy this dependable shade performer for years to come.
Companion Planting Guide
Selecting good companions for Pulmonaria ‘Cotton Cool’ focuses on plants that share its appreciation for medium moisture and deep shade. Consider pairing it with other texture providers such as Hosta cultivars that contrast the silver leaves with solid green or blue tones. Spring bulbs like snowdrops or blooming ephemerals work well as they complete their cycle just as the Lungwort foliage reaches its peak.
For an effective woodland garden tapestry, intersperse groups of your Pulmonaria ‘Cotton Cool’ with hardy ferns, such as Japanese Painted Ferns or Autumn Ferns, which provide fine texture contrast. Ensure that companion plants do not aggressively compete for surface moisture, as Lungwort performs best when it has access to consistent hydration, even if it is slow-spreading.
Seasonal Care Calendar
Early Spring (Pre-Bloom): This is the best time to assess the health of the foliage after winter. Remove any heavily damaged leaves from the previous year, though much of the foliage may remain. Apply a light layer of compost around the base of your Pulmonaria ‘Cotton Cool’ to enrich the humus content of the soil.
Late Spring/Early Summer (Post-Bloom): Crucially, remove the spent flower stalks immediately after they fade. This pruning helps direct energy back into foliage production and keeps the plant looking neat. Focus on consistent deep watering if spring rains have been sparse, as the plant will need steady moisture entering the summer months.
Late Summer/Fall: In hot, dry regions, the foliage may look ragged by late summer; simply trim back the diminished leaves to encourage any remaining clean growth or prepare for winter dormancy. Fall is the optimal time to divide any crowded clumps of Pulmonaria ‘Cotton Cool’ to maintain air circulation and plant vigor for the following season.
