PLANT OF THE MONTH DEEP DIVE
Mertensia virginica L. (Pers.) – Boraginaceae (Borage family)
Related to Forget-me-nots, Wild Comfrey, and Borage, Virginia bluebells feature true-blue flowers on coiled racemes.
The common name, Virginia bluebells, features ‘Virginia’ because in 1753 it was described from a plant collected in what was then the very large eponymous colony, and bluebells because of the attractive blue campanula-like (bell shaped) flowers. Our Fairy Garden experts assure us that the wee folk use bluebell flowers as brightly colored headwear.
A study of the history of its Latin binomial nomenclature is a roll call of some very important early modern scientists. The Latin Genus Mertensiawas erected by the German botanist Albrect Willhelm Roth (https://en.wikipedia.org/wiki/Albrecht_Wilhelm_Roth) to honor another German botanist, Frans Carl Mertens (https://en.wikipedia.org/wiki/Franz_Carl_Mertens), with Virginia Bluebells being the type species of the Genus (the form to which other similar/related plants would be compared). Unbeknownst to Roth, Famed Swedish botanist, zoologist, and “father of modern taxonomy”, Carl Linnaeus (https://en.wikipedia.org/wiki/Carl_Linnaeus) had already circumscribed the plant as Pulmonaria virginica L. Yet Another botanist and famed mycologist, Christiaan Hendrik Persoon, (https://en.wikipedia.org/wiki/Christiaan_Hendrik_Persoon), corrected the name. Check out his massive, two-part book Synopsis Plantae (https://bibdigital.rjb.csic.es/records/item/9812-redirection) made available online by the Real JardinBotanico, in Madrid, Spain.
Found throughout Central and Northern USA (see map: http://bonap.net/MapGallery/County/Mertensia%20virginica.png), from New York west to Minnesota and south to Alabama, Virginia Bluebells are widespread in PA though not in the Allegheny Mountain, Allegheny Front, or Glaciated High Plateaus or Poconos Mountain counties. They are indigenous to Allegheny County, where they are most frequent in lowland alluvial plains, and occasional on rich, moist uplands and hillsides. Local folklore indicates that it used to be much more common than today along Little Sewickley Creek and near the Ohio River; it’s now attenuated wild occurrences are attributed to real-estate development, mowing, and unsustainable overcollection for local gardens and horticultural trade. Numerous small wild populations do remain in the area, including in Walker Park. Further afield, Harrison Hills County Park in Northeast Allegheny County and Raccoon Creek Wildflower Reserve, part of Raccoon Creek State Park, in Beaver County, feature very robust (and protected) Virginia Bluebell populations. Several reintroduced Virginia Bluebells can be found along the alluvial plain trails at MRRNP.
Virginia bluebells are considered true spring ephemerals in that they push rapidly expanding leaves from their deeply seated taproots in very early spring, bloom by middle spring, and set seed and dieback to the ground by summer. Their entire vegetative cycle is complete by the time that overtopping canopy trees fully leaf out.
Spring ephemerals constitute a group of plants that contribute to the ‘vernal dam’ hypothesis, where the nutrients tied up in vegetative tissues that arise before overhead trees leaf out are made available to trees and other later leafing plants once the spring ephemerals go dormant. The decaying leaves of spring ephemerals serve as early summer fertilizer for later growing deciduous trees, while the autumn shed tree leaves fertilize both the trees and spring ephemerals. Thus, spring ephemerals constitute a critical part of nutrient cycles that reduce leaching of nutrients from a given ecosystem.
Virginia bluebell flowers in PA are visited by Bees (Megachilids, Mellitids, and Anthophorids, and perhaps others), Bumblebees, Butterflies, Moths, Wasps, and many other insects. Only butterflies, moths, and very long-tongued bees and bumblebees are able to drink nectar from the front of the flowers, thereby also effecting pollination of the flowers; some short-tongued bees and bumblebees (including large carpenter bees (Xylocopa) chew holes through the sides of the flowers to access the deeply seated nectaries. Wasps, beetles, flies, and ants will also take advantage of such easy access to nectar. Small bees and flies that visit front of flowers may be too small to effect pollination. These animals are considered “nectar robbers” because they take sugar-rich nectar from flowers without providing any pollination service in return. In the southern part of their range, migrating Ruby Throated hummingbirds also take nectar from the front of the blooms — acting as lesser pollinators.
Virginia bluebell flowers are usually blue when newly opened and not yet pollinated. The flowers buds start out as pink but change to blue as flowers open, thus informing flower visitors that the flowers now offer rewards. The richness of the blue is related to availability of Aluminum ions in the soil; AL rich, acid soils yield the deepest blue flowers. The color change is related to chemical changes that occur in the petals following pollination. Some plants naturally lack blue pigment though and only produce pink or white blossoms.
Very few animals eat Virginia bluebell leaves, which are known to be rich in potentially toxic Pyrrolizidine alkaloids, though white-tailed deer will browse on them. The starkly colored ‘Confused Haploa’ Moth (Haploa confusaLyman, 1887) relies on Virginia bluebells and wild comfrey (Cynoglossum (=Andersonglossum) virginicumL.) to feed its caterpillars. The caterpillars are bristly but also starkly colored in what may be an aposematic (hazard warning) color scheme. Perhaps these caterpillars derive some protection from predation thanks to their host plant chemistry — this has not been scientifically confirmed. Local footage has shown these caterpillars to be host to parasitoid wasps and tachinid flies.
After pollination, each Virginia bluebell flower can result in a 4 lobed fruit (a “schizocarp”) that bears 4 small, brown nutlets. These nutlets fall to the ground as the foliage senesces in late spring. The seeds require consistent moisture after falling from the mother plant; desiccation will result in either deep-seed dormancy or seed death. If the seeds do not fall on consistently moist soil they will not be able to germinate the following year; heavy deciduous leaf mats will prevent most seeds from reaching consistently moist soil. The seeds require several months of warm and moist conditions followed by several months of cold, moist conditions to escape germination inhibition systems. While roots often sprout in fall, leaves will only sprout as temperatures rise to consistently above freezing the following spring. Seedlings are small and are also easily smothered by dense deciduous leaf mats. Thus, scouring floodwaters or steep hillsides that defy leaf accumulation are required for successful seedling recruitment; hence natural floodplain and hillside habitats. Seedlings can reach blooming size in three to five years.
Love Spring Wildflowers? Go outside and see them! Check out Raccoon Creek Wildflower Reserve, Toms Run Reserve, and of course, Mary Roberts Rinehart Nature Park. And please consider donating to Mary Roberts Rhinehart Nature Park to support our continuing wildflower restorations and educational content.