The Lungwort Herb: A Silver Renaissance

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All of the various lungworts are part of the family known as Boraginaceae, with leaves ranging in shape from long to wide, from very narrow to heart-shaped and may be as short in length as 7 inches or extend to almost 2 feet in length.
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This silver beauty, known as ‘Excalibur’ is one of several cultivars with silver or white on its leaves. Other lungworts may have spots or be plain green.
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Lungworts vary in height from 6 to 12 inches and in flower color from pink to blue.
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The spotted leaves of Pulmonaria longifolia are long and narrow and provide an interesting backdrop when dark-blue blossoms appear.
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Each of the lungworts has markings so varied that based on the leaf shape and color, one might not appear to be even remotely related to another.

I’ve long been enamored of lungwort (Pulmonaria officinalis), delighting in its cheerful clusters of small pink and blue trumpet flowers bravely blowing in the cold northern wind, a herald of the new growing season ahead and source of the first nectar for returning hummingbirds. Its emerging gray- to cream-spotted, bristly, heart-shaped foliage looks good the entire growing season, and provides an attractive, carefree edging for perennial plantings. Who could ask for anything more?

But when we moved to our new home in the foothills of New York State’s Adirondack Mountains, I found that although lungwort was hardy enough for this Zone 4 climate, it didn’t thrive here.This fast-paced growing season can get hot and dry, and my common lungwort suffered in the light, fast-draining soil, even when planted in the shadiest conditions I could provide.

Then I learned that the spotting and blotching on lungworts’ leaves are an adaptation for survival in less than ideal conditions, as these blotches help prevent overheating. For this reason, I began looking for especially silvered types that might be more adaptable to a drier situation. What I discovered was an astonishing world of new, heavily silvered lungworts.

As if handcrafted by expert silversmiths, in infinitely varied markings, some are extravagantly spotted, others lavishly painted with a metallic sheen, still others combining silver overlay with splattered moons, on leaves of varying lengths and widths, some waved, all sporting showy flower clusters in designer shades from all white and ice blue to coral-raspberry. From humble cottage garden to high fashion, the ancient medicinal lungwort has shot up, almost overnight, to become a garden star, with silver varieties earning the highest accolades.

Form and function

As herb enthusiasts we can keep our heads by recalling lungwort’s history as a practical healing herb. Based on seventeenth-century thinking that a plant’s appearance suggested its curative powers, common lungwort earned a reputation for healing bronchial and lung problems because of its spotted (as if diseased) and roughly lung-shaped leaves.

Its role as a medicinal is preserved in the Latin genus name–“pulmonaria” referring to lung; the common name, “lungwort,” in modern parlance means “lung plant.” Contemporary herbalists claim that lungwort does indeed soothe bronchial complaints, while other authorities caution that preparations from the plant may actually damage lung tissue.

Natural habitat

The pulmonarias are native to the mountainous regions of south and central Europe, where they grow in the protection of deciduous trees, whose growth cycle perfectly matches the needs of the plants growing at their base. In early spring, bare branches let in the light that pulmonarias need to initiate new growth; as the trees’ leaves develop, they shield plants from summer heat; then as leaves fall and decay at the end of the growing season, they form an incomparable mulch that surrounds plant roots with the cooling moisture they need to survive and prosper. There’s no better guide to growing pulmonarias than trying to mimic their wild habitat.

Besides common lungwort, four of approximately eighteen species have been cultivated for more than 200 years; they vary in height when in bloom from 6 to 12 inches and bear flowers from pink to blue, sprouting leaves that range in shape from long to wide, from very narrow to heart-shaped, either plain green or spotted, and in length from 7 to 24 inches. P. angustifolia has bright, blue-violet flowers and narrow, unspotted dark-green leaves; P. longifolia has more narrow leaves, but its flowers are dark blue and leaves are well spotted silvery-white; P. montana is an especially vigorous early-blooming type with coral-red flowers and large unspotted bright green foliage; P. saccharata carries pink and blue flowers over oval, profusely spotted silvery-white leaves. For decades, virtually all cultivars were chance seedlings or natural hybrids of these species, originating in Europe around the turn of the century; pulmonarias are notoriously promiscuous self-breeders.

A new look for a timeless herb

The driving force of finding, selecting, breeding, and introducing the new look, which began in Europe about ten years ago, is Terra Nova Nurseries in Tigard, Oregon, a wholesale nursery dedicated to growing unusual plants. Its dynamic founder, Dan Heims, reports that Terra Nova is “conducting the most comprehensive hybrid pulmonaria seedling trials on earth,” probably no exaggeration if you are acquainted with this energetic self-proclaimed “hortiholic.” “

Over 2,000 pulmonarias,” he says, “have been sorted through our watchful eyes, and all but a very special few will be dismissed. We are seeing revolutions in form, foliage, and flower that will shake the industry. . .”

Daunted by catalog hype that claimed each introduction was a never-before-seen variation of leaf spotting, blotching, and flowers, resistant to powdery mildew (common in lungworts during a dry spell), slugs, and deer, I decided I would have to conduct my own field trials to find out just how they responded to less-than-ideal growing conditions. I don’t need beautiful prima donnas in my garden. This report covers a single season and focuses solely on foliage.

Trial specimens

From Dan Heims’ Terra Nova Nursery, I received three plugs each of eight types, to which were added three other pulmonarias from a friend’s garden; all of them, whatever their leaf markings, are bristly to the touch.

‘Apple Frost’. Spreading apple-green foliage dusted with a silver overlay, slightly ruffled; rose buds open to blue flowers.

‘Berries and Cream’. Silver leaves splotched, spotted toward ruffled edge; raspberry-pink flowers, maturing to purplish; hybrid of ‘Excalibur’ ¥P. montana ‘Red Start’.

‘British Sterling’. Irregular splotching to entirely silvered with green moon-splattered margin; magenta buds open to pink, age to blue; some claim the original cultivar no longer exists.

‘Cotton Cool’. Large leaves with silver spotting merging into a metallic overlay; blue flowers similar to P. longifolia.

‘Moonshine’. Rounded leaves with metallic silvery overlay, merging to spotted dark-green margins; small pale-blue flowers.

‘Polar Splash’. Large leaves with large silver spots, an arching habit; pink and blue flowers.

‘Raspberry Ice’. Tapered and frosted mint-green leaves, suede-like in appearance, edged with cream; raspberry-pink flowers.

‘Raspberry Splash’. Long, very narrow leaves of the longifolia type, heavily spotted; large clusters of burgundy buds open to salmon/raspberry-pink flowers; hybrid of P. longifolia and P. rubra.

‘Silver Shimmers’. Metallic overlay on long, large, ruffled leaves narrowly edged with a dark-green, spotted band; steel-blue flowers.

‘Silver Streamers’. Light-green foliage with spots that merge into metallic overlay, ruffled edge narrowly banded with tiny spots over a medium-green background; blue and rose-pink flowers.

‘Sissinghurst White’. Dark-green leaves with silver spots; pure white flowers; a classic pulmonaria now thought to be a hybrid rather than a cultivar of P. officinalis.

Preparation and planting for trials

Ground for the trial was prepared in the fall with the addition of four inches of compost-soil in the dappled shade of an ash, maple, and buckthorn bower with southwest exposure: indirect sun in the morning, heating up by noon, then cooling by mid-afternoon; nearby structures and similar light woodland creates a generally protective environment.

Terra Nova pulmonaria plugs were planted on April 13 in a wave that followed the contours of the land. Three of each type followed one another, 16 inches apart; each planting hole was enriched with a trowel of compost soil (three-year-old composted barn waste), then mulched with additional compost soil, and topped by wood chips. It rained that day and overnight, a good omen. . . or so I thought. Three days later, temperatures soared to 80°F and everyone was digging out shorts and bathing suits–we took our first outdoor shower.

On April 19, a moderate earthquake shook the North Country (its epicenter was twenty miles away), a deep rumble that sounded like ten heavy-duty trucks rolling by. This was followed by a complete turnaround in the form of snow, sleet, and cold rain for the rest of the month. I hardly dared look at my trial planting, but since we passed it every day on the way to the barn I couldn’t avoid it. They held on–no prima donnas.

By mid-May, temperatures were seasonably spring-like and the little plants were all accounted for, and most were becoming silvered beauties (the few slow growers were smaller plugs to begin with). My friend’s donations–‘British Sterling’, ‘Raspberry Splash’, and ‘Sissinghurst White’–were added to the trials, but planted among existing beds with partial shade in compost-enriched soil.

As the season advanced and I weeded around each plant, I observed them closely, marveling over each splatter, waved edge, dusted leaf, and exquisitely marked margin. It’s easy to see how pulmonaria variations excite the collector. As the foliage spread over the ground, it created an undulating silver ribbon, especially bright at dusk.

Trial results

Despite soil emendations, plants began to suffer the effects of prolonged drought during August and September when temperatures reached the high 80s and low 90s for weeks at a time. I was used to afternoon wilt, but I became concerned over foliage burn, so I watered plants on the hottest days. Pulmonarias least affected by these conditions were ‘Apple Frost’, ‘Raspberry Splash’, and ‘Polar Splash’, all spotted or splattered types. It would appear that those closest to common lungwort are among the toughest for heat and drought. To improve conditions I will add more compost soil to create a deeper soil base and I will more heavily mulch plants (unless it’s a wet season).

None of the pulmonarias suffered from powdery mildew, but the foliage of ‘Cotton Cool’ and ‘Berries and Cream’–both silver overlay types–was more attractive to slugs than others; some spotted reversion was noticeable in outer leaves of ‘Berries and Cream’ and a few others, but new growth was true to type. None was sampled by deer.

As cooler temperatures prevailed by mid-September, and we experienced a few showers and heavy rain, all pulmonarias–except ‘Sissinghurst White’, a slow starter–perked up and showed themselves off to advantage. From small plugs to mature plants, each cultivar displayed its true form, and I decided I much prefer the clean, arching shape of ‘Silver Streamers’, ‘Moonshine’, ‘Polar Splash’, and ‘Raspberry Splash’ to the flat-leaved, low-growing types such as ‘Cotton Cool’ and ‘Silver Shimmers’, which may make them more subject to slug damage; other types appear in between the spreading and arching form.

As for vigor, there is no contest. ‘Raspberry Splash’ is a very vigorous pulmonaria, quicker to develop than common lungwort. I divided the original clump into seven separate plants in late May. They never showed any sign of wilt, even though they were irregularly watered. By September, I re-divided the planting to create a hedge effect for a mailbox garden; mature leaves were cut back and within a week, plants had sprouted new foliage. ‘Raspberry Splash’ combines the best traits of its parents, P. longifolia and P. montana, the latter a thin-leaved, non-spotted type that I know from experience does not tolerate dry conditions. ‘Sissinghurst White’, adversely affected by drought, held on, and I anticipate it will become a strong grower; in this respect it is similar to common lungwort (one of its parents), slow to start but tough once established. ‘White Wings’, a shorter plant with pink-centered white flowers, is supposed to be more vigorous.

Lungwort companions

All of the pulmonarias are stunning foliage plants that bring brilliant light shade. They combine well in early spring with daffodils, wild bleeding heart (Dicentra eximia), then later with lady’s-mantle, heucheras (try ‘Purple Palace’ with the most silvered pulmonarias), blue hostas (‘Blue Cadet’, ‘Blue Angel’), and ajugas (‘Caitlin’s Giant’). The new silvers also make brilliant companions for each other–moon-spattered green leaf against solid platinum, silver dust against silver streak enhanced by a surrounding carpet of dark earth. The pairings, like the pulmonarias themselves, are without end.

The best of these blessed plants

Which is the fairest of them all? Which pulmonaria most exemplifies the new look while retaining tolerance of less than ideal conditions, resistance to slugs (the primary concern for pulmonaria lovers), and vigor? While ‘Raspberry Splash’ is the most vigorous and most reliable in dry conditions, it’s not the most beautiful (perhaps in bloom); the extremely metallic types have a hard appearance I don’t associate with pulmonaria, and some, such as ‘Cotton Cool’, became riddled with slug holes; ‘Polar Splash’ grew very well and suffered few slug holes, but in appearance it is too like an oversized common lungwort with larger, more brilliant spotting.

My vote for the best overall new look goes to ‘Apple Frost’ and ‘Moonshine’, which between them display the silver variations we now associate with the pulmonaria revolution. ‘Apple Frost’ has well-shaped full foliage and is entirely spattered and blotched, merging toward tiny moons on its green edges. ‘Moonshine’ displays a silver overlay (not quite platinum) and its inner rosette of leaves a cool lime-green, its outer dotted, darker green edges a pleasing contrast. Needless to say, new silver pulmonarias are waiting in the wings to impress us with their stunning designs, and although I may grow them, my Pulmonaria officinalis is still the essential lungwort, a more homey type for the cottage garden.

Jo Ann Gardner is an avid gardener, writer, and cook who resettled in the Adirondacks. She and her husband, Jigs, have written a book called Gardens of Use & Delight (Fulcrum Publishing, 2002).

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