As the spring ephemeral wildflower show in the Potomac gorge slowly ramps up, the most eye catching plant must be Mertensia virginica (Virginia bluebells, Boraginaceae). The pale green leaves pop up in floodplains and moist to wet woodlands, in clumps that stand up to two feet tall, and then flowering shoots emerge. The blooming period is three or four weeks long; the leaves last another few weeks after that, then die back and the plants are done for the season.

The inflorescence is a cyme. The flowers have five petals fused into a long, lobed tube; a much shorter corolla formed from five sepals; five stamens, and a single pistil.

Year after year, what I find fascinating is the color display. The vast majority of bluebells are an intense blue (I call it borage blue), but sometimes they will be pure white, or pure pink, or violet-tinted, or even pink and blue on the same plant. I’ve seen several possible explanations for this, but nothing definitive.

As for the pure white and pure pink bluebells, I’m going to guess that those are genetic variations. I’ve seen the same stand of pink ones three years in a row now, and the same stand of white bluebells every year since 2011. I’ve also seen the violet-tinted ones in the same place two different years.

violet-tinted

pure white (even the buds are white)

This post is dedicated to my friend Brad, who in early 2014 talked me into starting this blog, which is three years old today. 

Mertensia virginica; Boraginaceae

Nothing proclaims spring’s arrival in such a gloriously gaudy way as the blossoming of Virginia bluebells.  When the foliage first emerges from the ground, it’s purplish brown in color.  As the plant grows and the inflorescence unfolds, dark pink buds turn paler pink and then finally open in bright borage blue, which fades as the flower ages.  The fully opened leaf is a pale green, with a bluish cast.

I love the color show.  Every year I visit one particular clump of pure white Virginia bluebells.  But this year I found something new.  Apparently not unique, but fairly rare:

That’s right – pink Virginia bluebells.  I swear to you I did not adjust the color in Lightroom.

The internet is so full of information that I can’t sift through it all to find answers to my questions.  I’ve assumed that the white-flowering plants are genetic variations, but what accounts for the pink?  Genetics, soil pH, growing conditions?  This lone clump of pink bluebells was near other (blue) bluebells, but not right in the midst of them – it was a little off by itself, further from the river.

So help me I’m tempted to pull out the old soil pH meter and go back and do some testing.

One internet site states that the pink in the buds is due to the presence of anthocyanin, but that the plant increases the flowers’ alkalinity in order to change the color to blue in order to attract pollinators.  That certainly sounds authoritative, but I’d love to know what his sources were.  Is it reasonable to assume this mechanism failed in the case of the pink flowers?

And then there’s this:

Again, no messing with color during processing.  It’s a little hard to tell, but this clump had a distinct violet tinge to it, different from the faded blue of pollinated flowers.

If there’s such a thing as “normal” in this remarkable plant, it looks something like this:

Virginia bluebells like wet soils – they’re found near streams, in bottomlands and floodplains where they get both sun and shade from deciduous trees.  By the time the leaf canopy is established, they’re done blooming and the foliage is dying back to the ground, leaving no trace of this woodland wonder.

Where Virginia bluebells are found, they tend to be ubiquitous.  They range over most of the eastern US and Canada, but are missing from a few New England states.  They are threatened in Michigan and exploitably vulnerable in New York.