Pulmonaria, Pulmonaria, Pulmonaria
Pulmonaria 'Dark Vader'|
photo by Terra Nova Nurseries, OR
by Tony Avent
Plant Delights Nursery Inc.
9241 Sauls Road
Raleigh, NC 27603
There are few plants quite as interesting in the spring woodland garden as the pulmonarias (lungworts). Pulmonarias are an excellent bold-textured woodland perennial that contrasts well with other early season plants such as hellebores, ophiopogons, ferns, Iris cristata, along with other spring ephemerals in getting the spring garden off to a great early spring start. You would think that these durable early spring bloomers with attractive foliage would be grown everywhere, but alas no. Perhaps with a name like lungworts, it's no wonder that few folks put these in their plant grocery carts.
The name pulmonaria arose from the foliage, which is often green with white spots, resembling a diseased lung ... hence the common name lungwort ... and the Latin translation, pulmonaria, which became the name for the genus. Herbalists have long decried that when a plant resembles a particular body part, it must have medicinal properties to cure that particular part of the body. Hence, the continued use of pulmonaria to treat many respiratory ailments.
The silver spots on pulmonaria leaves are actually the result of foliar air pockets, used for cooling the lower surface of the leaves. These air pockets mask the appearance of chlorophyll in the leaves, creating the foliar patterns that we enjoy as gardeners. The logical conclusion is that cultivars with more silver in the leaves should be able to tolerate more heat and possibly sun.
Pulmonarias are perennials that grow from a deciduous basal rosette, usually no more than 6-10" tall with a spread up to 2'. Pulmonarias flower in late winter/very early spring, some often beginning around the end of February. The flowers, most of which emerge usually either pink or violet, typically change to blue as they age. The flowers are borne in corymbs on short stalks that reach just above the foliage. Pulmonarias generally retain their foliage until late winter, becoming mostly deciduous (depending on parentage) just before the new season's flowering and regrowth begin.
photo by Plant Delights Nursery, NC
Pulmonarias are members of the Boraginaceae family and first cousin to other well-known garden favorites such as myosotis (forget-me-not), brunnera, symphytum, and mertensia (Virginia Bluebell). The genus pulmonaria is composed of 16 species, although only 8 are known in cultivation. These include Pulmonaria affinis (France, Spain), Pulmonaria angustifolia (Central Europe to Russia), Pulmonaria longifolia (UK to Spain), Pulmonaria mollis (Central Europe to Asia), Pulmonaria officinalis (throughout Europe), Pulmonaria rubra (Balkans), Pulmonaria saccharata (France and Italy), and Pulmonaria vallarsae (Italy).
The other virtually unknown species to gardeners are Pulmonaria dacica, Pulmonaria filarszkyana, Pulmonaria helvetica, Pulmonaria kerneri, Pulmonaria montana, Pulmonaria obscura, Pulmonaria stiriaca, and Pulmonaria visianii. Pulmonarias hail from a native range encompassing much of Europe and into Russia. In the wild, they usually grow in deciduous woodlands. Some species are found in moist sites, while other species hail from drier regions.
Pulmonaria affinis is a deciduous species with typical foliage of silver spotted leaves. It is one of the best pulmonaria species for sun tolerance, and it is only represented in the trade by one cultivar, Pulmonaria 'Margaret' (Hardiness Zone 4-7)
Pulmonaria angustifolia has been the source of much nomenclatural confusion, since the plant in the horticultural trade as Pulmonaria angustifolia doesn't match the real Pulmonaria angustifolia. It is still unknown whether the Pulmonaria angustifolia in commerce is an unknown species or a hybrid group. There is only one cultivar of the true Pulmonaria angustifolia ... a plant that goes by the invalid name of Pulmonaria angustifolia 'Alba'. There are several cultivars of the fake Pulmonaria angustifolia, the most commonly grown being Pulmonaria 'Blaues Meer'. These fake Pulmonaria are stunning plants with green foliage and known for their intensely cobalt blue flowers. (Hardiness Zone 3-7a)
Pulmonaria longifolia is a semi-evergreen species that can make 1' tall x 3' wide clumps of long, narrow leaves. Like Pulmonaria affinis, it has good sun tolerance. There are three cultivars of Pulmonaria longifolia in commerce including: Pulmonaria 'Bertram Anderson', Pulmonaria 'Ankum', and Pulmonaria 'Dordogne'. Because Pulmonaria longifolia is such an exceptional garden plant with good mildew resistance, it has been used in a number of newly created hybrid pulmonarias, especially the heavily spotted forms from South and Central France, known as Pulmonaria longifolia ssp. cevennensis. (Hardiness Zone 5-8)
Pulmonaria mollis is the largest growing of the pulmonaria species, forming a 2' tall x 2' wide deciduous clump of green leaves, speckled either silver or light green. It also has good sun tolerance. Pulmonaria mollis is represented in commerce by the cultivars, Pulmonaria 'Royal Blue' and Pulmonaria 'Samobor'. (Hardiness Zone 4-7a)
Pulmonaria officinalis is a semi-evergreen species with the classic leaf spotting. Pulmonaria officinalis is represented in commerce by several cultivars including Pulmonaria officinalis 'Alba', Pulmonaria 'Blue Mist', and Pulmonaria 'White Wings'. It has also been used in many early hybrids, but because it is so mildew-prone, many of the newer hybrids exclude this species. (Hardiness Zone 4-7)
Pulmonaria rubra is a semi-evergreen species to 1' tall x 18" wide with large, solid green, hairy leaves. Unlike most other pulmonaria species, the flowers are salmon red. There are a number of selections of Pulmonaria rubra in commerce, but since they have poor heat tolerance, they are confined to cooler summer climates. These cultivars include Pulmonaria 'Barfield Pink', Pulmonaria 'Bowles Red', Pulmonaria 'David Ward' (white-edge leaves), and Pulmonaria 'Redstart'. (Hardiness Zone 5-7a)
Pulmonaria saccharata is a semi-evergreen species with typical silver-spotted foliage, forming an 18" tall x 20" wide clump. Selections of Pulmonaria saccharata in commerce include Pulmonaria 'Leopard', Pulmonaria 'Mrs. Moon', Pulmonaria 'Pink Dawn', and Pulmonaria 'Reginald Kaye'. (Hardiness Zone 3-7).
Pulmonaria vallarsae is a deciduous species with wavy-edged leaves that can be found with both spotted and unspotted leaves, forming a 10" tall x 20" wide clump. There are no known confirmed cultivars of Pulmonaria vallarsae in commerce. (Hardiness Zone 6-8).
Over the years, the number and quality of pulmonaria hybrids has dramatically increased and improved. Most of the early hybrids from the EU countries, where pulmonarias grow native, were discovered as wild or garden origin seedlings. It was Dan Heims of Oregon's Terra Nova Nurseries who really began a directed breeding program with pulmonarias. Only a handful of the EU selected pulmonaria cultivars are available in the US, and many only exist in small specialty nurseries in the EU. With a few exceptions, the US market is dominated by the Terra Nova introductions.
The current generation of hybrids were ushered in by Pulmonaria 'Roy Davidson'. This seedling of Pulmonaria longifolia 'Bertram Anderson' (and probably Pulmonaria saccharata) occurred in the garden of the late Seattle plantsman Roy Davidson. Like its parent, Pulmonaria 'Roy Davidson' is very tolerant of heat and humidity. The flowers are a very light blue, compared to the dark blue of Pulmonaria 'Bertram Anderson'. This introduction is the parent of many of today's best cultivars.
Another group that changed our concept of Pulmonarias was the solid silver leaf form, first known as Pulmonaria saccharata 'Argentea'. Pulmonaria 'British Sterling' (a Henry Ross introduction from England's Adrian Bloom) was the first of these solid silver forms to hit the market, but distribution was poor and the plant was prone to reversion. Pulmaonaria 'Majeste', a much improved selection (first sold in 1988) soon followed, and this French introduction from Didier Willery of La Ferme Fleurie Nursery was a much superior plant with a better PR agent. Pulmaonaria 'Majeste' (a seedling found near a clump of Pulmonaria 'Mrs. Moon') has velvety leaves of pure silver ... not a speck of green on the leaves. I first saw this at the old Washfield Nursery in the UK in the mid-90s. Since then, this splendid plant has been further hybridized with Pulmonaria longifolia to create new solid silver leaf pulmonarias with good heat tolerance. One of my favorites is Pulmonaria 'Samourai'. Ten years after the introduction of Pulmaonaria 'Majeste', Didier introduced this cross of his original Pulmaonaria 'Majeste' and Pulmonaria longifolia var. cevennensis. Pulmonaria 'Samourai' makes a superb clump of narrow, pure silver foliage, topped with cobalt blue flowers in spring.
Pulmonaria 'Spilled Milk', and Pulmonaria 'Excaliber' PP 8958, patented in 1994, started the pulmonaria revolution at Oregon's Terra Nova Nurseries. Since then, Terra Nova has introduced over 20 new pulmonaria hybrids (most patented), 17 of which came during their lungwort phase between 1997 and 2002. (through the end of 2009). Of those, 11 are still currently in commercial production. Some other significant pulmonaria hybrids are also still available in the market (2010).
Pulmonaria are short-lived plants by nature and the only way to maintain them on a long-term basis is to divide the clumps every 3-5 years. I like to do this in fall and winter, when the entire clump can be lifted, teased apart, and replanted. Actually, any season that you have time to divide the plant will work. In the garden, pulmonarias prefer moist, well-drained soil that is rich in organic matter. While they are quite drought tolerant, a consistently dry soil doesn't give the best long-term results.
I have also found that light shade with a few hours of morning sun is preferable. While lungworts will grow for a short time in very dark settings, this is not the ideal condition for best performance. In deep shade, where air circulation is often less than ideal, many of the cultivars will tend to get powdery mildew on their foliage during the summer. While this is unsightly, it seems to cause little problems for the plants, unless the plants also suffer additional stresses from poor growing conditions. The diseased foliage can be removed and discarded and the plant usually comes back with fresh undamaged foliage. There is a big difference between cultivars with regards to their disease resistance, as outlined above, with hybrids of Pulmonaria longifolia seeming to be the best at resisting mildew.
Pulmonarias are quite easy to propagate. I've already mentioned dividing plants, but cultivars can also be increased by root cuttings. Any pulmonaria roots that are the width of a typical pencil lead can regenerate new plants. Root cuttings need to be 2-3" long and stuck vertically with the end furthest from the plant crown down ... polarity is very important. Pulmonaria will also seed in the garden in well prepared, organic soil, so watch closely and you may discover something unique.
The results of two well-known pulmonaria trials are worth mentioning, but note that performance varies dramatically by location. I urge you to seek out both the results from the Chicago Botanic Garden trials, published in 2001 and the Royal Horticultural Society Trials, published in 1999, if you live in climates similar to these. Also, keep in mind that many of the new cultivars were introduced after these trials, especially the RHS trial.
Bennett, Marsha (2003). Pulmonarias and the Borage Family, Timber Press.
Hewitt, Jennifer (1999). "Well Spotted" The Garden.