Serious gardeners and botanists often ignore the common garden or hybrid petunia. It is ubiquitous in nurseries, grocery store “garden” sections, and hanging baskets throughout North America (I imagine Europe as well, but am speaking from my own experience). So ubiquitous, that I have learned to more or less discount it as something of particular interest. The only petunia previously featured on Botany Photo of the Day was Petunia patagonica, which was is described as “nothing at all like the overused, abused annual Petunia hybrids. But despite receiving the snobbery of botanists, the petunia, like all plants, has its own story to tell.
Despite its presence in most of the planter boxes of North American small towns, the heritage of the garden petunia is not well understood. In the 19th century, purple-flowered petunia specimens were transported to European gardens from South America, where they were quickly popularized and hybridized with the white-flowered Petunia axillaris. Gardeners reveled in the multitude of colours that they were able to produce, the ease of which these could be grown, and the long blooming season of these new hybrids. In all of this horticultural innovation, seemingly no one kept track of the crosses that were occuring, so that the purple-flowered ancestor of the common petunia is a mystery.
The prevailing view is that a member of the morphologically-similar Petunia integrifolia species complex was the purple-flowered petunia that sired the garden hybrid. However, this does not provide much certainty, as the Petunia integrifolia species complex consists of five taxa–and other purple petunia species could not be ruled out altogether.
Recently, a group of Brazilian botanists set out to solve the mystery of the hybrid petunia’s lineage, using plastid and nuclear markers to determine and test the direction of crossing that was likely to have occured (see: Molecular Insights into the Purple-Flowered Ancestor of Garden Petunias). These botanists learned that the most likely purple-flowered ancestor of the garden petunia is one of the five in the Petunia integrifolia species complex, Petunia interior. This species is native to the very southern tip of Brazil as well as the Missiones Province in Argentina. However, the botanists also concluded that petunia lineage sorting appears to be incomplete; this means that different taxa of petunia, including the garden hybrids, can possess many of the same genetic markers without having a direct lineage. In other words, uncertainty remains as to exactly what romance happened between the purple-flowerd and the white-flowered petunias in those 19th century gardens.
Even though the foundational origins of the cultivated petunia remain murky, modern hybrids like ‘Balpevac’ typically have origins that are well-documented. This is required in order to prove novelty in securing Plant Breeders’ Rights and/or Plant Patents (and thereby receive protection against unlicensed propagation or theft of intellectual property). Additionally, and the cause of much confusion, cultivated varieties submitted for PBR or PP are subsequently trademarked, so that a trade name with more general appeal than the true cultivar name is used to market the hybrid to the public. In this instance, Petunia ‘Balpevac’ is generally sold as Black Velvet, though I’m not able to discern whether this is a registered trademark or simply a trade designation (in which case, it would have less commercial protection around the name). Read a bit more about the breeding of Petunia ‘Balpevac’ via the Toronto Star: Petunia petals as smooth as black velvet.
Lastly on the topic of plant breeding and petunias, Science magazine has an excellent couple articles about a Finnish plant biologist at a train station leading to the discovery that genetically-engineered petunias had illegally arrived into the USA and Europe marketplaces–and the subsequent “transgenic petunia carnage of 2017”: U.S. flower sellers rush to destroy illegal GE petunias and How the transgenic petunia carnage of 2017 began. Please note that Petunia ‘Balpevac’ is not one of these transgenic hybrids.