What’s Up? White Flowers

White flowers recently seen in the greater Carderock area.

Virginia bluebells (Mertensia virginica; Boraginaceae) are of course normally blue, but every once in awhile you’ll see a stand of white ones. Look for them in floodplains and adjacent moist slopes.



Look for twinleaf (Jeffersonia diphylla; Berberidaceae) on rocky slopes along Billy Goat B; it will likely be done blooming by tomorrow.



Moss phlox (Phlox subulata; Polemoniaceae) should be blooming for at least another month. As you can see from the photo, it doesn’t need much soil. Look for in on large rock formations along the Potomac River.



Lyre-leaved rockcress (Arabidopsis lyrata; Brassicaceae) is another rock-loving species. They’re so wispy they can be hard to see, but should be blooming for at least another month.



Bloodroot (Sanguinaria canadensis; Papaveraceae) is almost done blooming. You can find it in rich woodlands, usually in colonies.




Early saxifrage (Micranthes virginiensis; Saxifragaceae) grows in thin soils in rocky woodlands. It’s one of the earliest bloomers but lasts for a fairly long time.



Rue anemone (Thalictrum thalictroides; Ranunculaceae) is just starting to bloom. It’s common in the Maryland piedmont but for some reason there isn’t much of it in the Potomac gorge. Look for it in the very open wooded areas near the Marsden Tract. It should bloom for another month.

Dutchman’s breeches (Dicentra cucullaria) and the closely-related squirrel corn (D. canadensis; Papaveraceae) are both blooming in moist woodlands. In past years I’ve observed that the latter starts blooming a week or so after the former, so if you want to see both, go hunting soon. Neither lasts for long.



Culver’s root
Veronicastrum virginicum
(formerly Scrophulariaceae)


I’m partial to tiny, subtle flowers, but it’s hard not to love a plant like this. Although the individual flowers are small, they’re crowded into dense spikes up to eight inches long. The spikes occur in whorls in the upper nodes, surrounding a towering central spike. The whole effect is spectacular, especially when you find a plant that’s as tall or taller than you are.



seen from a distance; notice the Baptisia australis growing to the left


I first saw Culver’s root two years ago, growing along a slope so steep I had to almost climb to get to it. Earlier this year I saw a few plants growing next to the blue false indigo I was obsessed with; later I reported that they’d been browsed by something. But a few days ago they had bounced back, tall spikes filled with buds.



a little closer


To my delight I spied a third patch on the peninsula I visited (post from July 3), and interestingly the plants were growing right next to a big stand of blue false indigo. Clearly they enjoy they same growing conditions: wet soils in full sunlight. Culver’s root would be lovely in the back of a rain garden, maybe alongside joe pye weed. It’s a hardy, adaptable plant that is available in the nursery trade.



a whorl of spikes and leaves at the uppermost node


Worldwide there are about a dozen species of Veronicastrum, but V. virginicum is the only one in North America. It’s found in the eastern half of the US and Canada, as far west the the easternmost portions of the Great Plains states. It’s threatened in Massachusetts and New York and endangered in Vermont. In Maryland in grows in the Piedmont and part of the Coastal Plain (and in Garret County).


A Whole Lot Going On Now


ramp; wild leek
Allium tricoccum


Thursday morning I was able to get out for a few hours of hiking along the Billy Goat C trail. Along the trail itself, just a few things were blooming: honewort (past its prime), white avens, ramps. Lots of stinging nettle. Down in the river, water willow was just starting to open, and along the canal there was some tall meadow rue.

I braved poison ivy and a lot of flood detritus to get out to my favorite peninsula, the one with a pond in the middle, and that’s where the wildflower show was:

  • nodding onion
  • American germander
  • common arrowhead
  • buttonbush
  • joe pye weed (buds)
  • common milkweed
  • swamp milkweed
  • seedbox
  • fleabane
  • fringed loosestrife
  • horse nettle
  • wild potato vine
  • water speedwell (new to me!)
  • trumpet creeper
  • white vervain
  • blue vervain



nodding onion
Allium cernuum


Also, I found another stand of blue false indigo, past bloom of course but with big seedpods. This is a good find that I’ll be reporting to the Maryland DNR, since it’s a listed species (S2/Threatened).

There were invasive aliens, of course, mostly common St. Johnswort and a mustard species. A small stand of plants with pretty purple spikes is probably purple loosestrife, a particularly aggressive alien. It was growing amid buttonbush and halberd-leaved rosemallow (not yet blooming) right at the pond’s edge.

There were two other species, but as they’re particular favorites and since I think I got some good pictures, I’ll save them for more detailed posts in the next few days.



Cephalanthus occidentalis

Carderock, May 2


The morning of May 2 I set out for a quick survey of the greater Carderock area, with the goal of shooting some long-tube valerian, a highly state rare/endangered species that grows in several different locations in the Potomac gorge.


Along the way, on the towpath between the Billy Goat C and Billy Goat B trailheads, I noticed that a lot of trees along the stone retaining wall were missing.

What the heck? Wondering why, I decided to call the park and inquire when I got home.

I didn’t need to. A few hours later, on the way back, I saw a ranger taking photos, so I asked him about it. In summary, the retaining wall is historic, and it’s been in danger of being damaged by the trees, some of them were quite large. If one had gone down in a storm, the root mass lifting out of the ground could have caused a breach in the wall. Not only would that severely damage the canal and make that part of the towpath unusable, but an 8′ diameter sewer main, part of the Potomac Interceptor sanitary system, runs along there. It, too, would be severely damaged by a breach in the wall.


The flags marked a line 20 feet from the base of the wall; all the activity is being kept within that zone. They will be installing some monitoring equipment in order to track changes to the wall in coming years.

My main concern, of course, was damage to plant communities. Good news: the park always has an expert come in for a plant survey before they do any work.


Annoyingly the narrow strip of land between the towpath and the wall gets moved every few weeks, but if you go now, you’ll see some lyre-leaf sage blooming in there. The plants are quite short, but year after year they survive the mowers.


The spring ephemerals are almost entirely gone, just a few spring beauties left. Observed blooming on May 2:


  • wild blue phlox (waning)
  • star chickweed
  • Virginia waterleaf (just starting)
  • Coville’s phacelia (past its peak)
  • long-tube valerian
  • clustered snakeroot (just starting)
  • golden Alexanders (S3 – rare to uncommon)
  • rattlesnake weed
  • hairy beardtongue
  • moss phlox (waning)
  • field chickweed
  • wild geranium
  • rue anemone
  • lyre-leaved sage
  • Rubus species (probably a dewberry)
  • azure bluets
  • dwarf cinquefoil
  • plantian-leaved pussytoes (waning)
  • bastard toadflax
  • fringetree
  • deerberry
  • alumroot
  • violet wood sorrel
  • wild pink (a day or two away from being done)
  • spring forget-me-not
  • Virginia spiderwort
  • common wood sorrel
  • Philadelphia fleabane