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.

Late March

Things are still moving along slowly in the Potomac Gorge, but with warmer weather coming I expect the show will really get going soon.

On March 25 I found large patches of harbinger-of-spring blooming near Billy Goat B.


The bluebell buds should open in the next few days.





A few cutleaf toothwort are out, and lots of spring beauties, of course. Spicebush is also starting to bloom.




And there were several bloodroots flowering near Old Angler’s.

See LW’s comments on the last post for an update of the area around Carderock.

Mid-April Update

rue anemone blooming in a patch of violet wood sorrel leaves (no flowers yet) at Rachel Carson Conservation Park

Along the Billy Goat B trail on Tuesday, there were still plenty of spring beauties, star chickweed, and field chickweed. While Virginia bluebells are waning fast, wild blue phlox is past its peak but still going strong. Plenty of Coville’s phacelia, but I wasn’t able to find any Miami mist. In a few places along footpaths between the trail and the towpath you can find wild geranium in full bloom, too. Close to the river a few stands of golden Alexanders are open.

azure bluets, violet wood sorrel, and wild pinks in dappled shade near Carderock

Small patches of violet wood sorrel are blooming along the trail and in the greater Carderock area, which is looking great, with plenty of azure bluets and wild pinks in the rocky areas. Plantain-leaved pussytoes are blooming, too, and dwarf cinquefoil is just starting. Bastard toadflax is budding up and a few days from opening. A few days behind it, perhaps, will be rattlesnake weed, also budding up. Sessile bellwort is done already, and the yellow violets are mostly done, but there’s plenty of creamy violet still. Toadshade is hanging on, but most of the other ephemerals there are done (except spring beauty, of course).

Look up: flowering dogwood and pawpaw are in full bloom.

flower buds on pinxter azalea

Over at Rachel Carson Conservation Park, the pinxter azaleas and showy orchis are in bud; the former will be open within a few days, the orchis in maybe a week. There are a few stands of azure bluets by the river, and gobs of rue anemone and spring beauty everywhere. Look for mayapples and jack-in-the-pulpit, too. There are several nice stands of perfoliate bellwort along the Fern Valley trail.

I also found a new-to-me shrub that I haven’t identified yet. Hopefully it’s something good and interesting and I can write about it in a few days.

perfoliate bellwort at RCCP

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

Three Views

And here’s the final view for 2015, after a few days of rain. Don’t forget to visit the Three Views page to see how things change month-by-month.

December 4
41 degrees F at 9:40 am; sunny 


9: 54 am EDT  31mm  f/8.0  1/250sec  ISO 100

Billy Goat B trail, east end, looking southeast across a narrow channel toward Vaso Island


11:11 am EDT  30mm  f/10  1/100sec  ISO 100

Billy Goat B, mid-way between trailheads, looking upstream (more or less northwest) with Hermit Island on the left.


11:45 am EDT  28mm  f/8.0  1/640sec  ISO 100

boat launch ramp near Old Angers Inn, looking downstream and more or less south