Tag Archives: Potomac River

More Showy Summer Flowers

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a huge stand of New York ironweed in a nearly dry river channel

As I worked my way along the Potomac River’s muddy banks last week, I watched for New York ironweed (Vernonia noveboracensis; Asteraceae). I hadn’t seen it in the wild in several years. I didn’t find it Monday or Tuesday, but I saw hundreds of plants on Friday. Some were only knee high, others were over seven feet tall; some grew singly, and others grew in huge colonies. Now I appreciate the word “weed” in its name.

Two (or maybe three, it’s not quite clear) of the 20 or so Vernonia species found in the US are native to Maryland. V. noveboracensis is a wetland species, while V. glauca is an upland species, so the easiest way to distinguish between them is to note where they’re growing.

One of the neat things about this species is that the inflorescence has only disc florets; there are no ray florets at all.

 

 

 

Joe-pye weed is another tall forb with showy flowers. I see it more often along the C&O Canal than along the river. There are two species found in the Maryland piedmont; this one is Eutrochium fistulosum, which prefers sunny, wet places. The other species (E. purpureum) prefers upland areas. Joe-pye weed is another aster family plant with only disc florets. By themselves they aren’t much to look at; it’s the huge masses of multi-flowered heads in multiple inflorescences that make the plants so showy.

 

 

 

 

 

Believe it or not, plants not in the aster family are blooming now, too. These two are in the mallow family (Malvaceae). The white one with the simple leaves is Hibiscus moscheutos (swamp rosemallow); the pinkish ones with the deeply lobed leaves are Hibiscus laevis (halberd-leaved rosemallow). Be wary of using color to tell them apart, as colors in both species can vary, especially in different parts of the country. The leaf shape is a more reliable differentiator.

Swamp rosemallow is common in the coastal plain, less so in the piedmont, and although halberd-leaved rosemallow is on the Maryland DNR watchlist, it seems fairly abundant along the Potomac in Montgomery County.

Last one for today: Lobelia cardinalis (cardinal flower). I’m always stunned by just how red these flowers are. I’ve never seen a wildflower in this area with such intense color. I was surprised by how common it is: look at the quad map from Maryland Biodiversity Project!

next time: something new

Summer Showstoppers

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the Potomac River in early August, looking upstream from near Cabin John Creek

Spring is the time for the small, subtle things that emerge, grow, leaf out, bloom, fade, and die back to the ground before you know it. For many ephemeral species, you have two weeks at best to see the flowers.

thin-leaved sunflower stretching towards the sun

Summer, though… Summer is the time for big, showy, outrageous things. Plants taller than you are (joe-pye weed), leaves bigger than your hand (hairy leafcup), lurid colors (cardinal flower).  Many of these you won’t find in the woods, where flowers tend to be small (jumpseed, Indian-tobacco). The showy plants tend to like sunlight, so look for them in open woodlands, or at woods’ edge, or in meadows, or best yet, along riverbanks.

common evening primrose growing along a steep riverbank

That’s where I was last Monday and Tuesday. The weather was so nice, I couldn’t resist going to the Potomac Gorge to do some botanizing. Scrambling down steep banks and treading along the waterline I found over 40 different species of plants in flower.

Today I’m going to focus on the large yellow ones.

 

Common evening primrose (Oenothera biennis; Onagraceae) is found in every county in Maryland and most of the US.  It can grow over 6 feet tall in a variety of habitats. It’s hard to say how tall these were, as they were growing up a steep slope, but the ones closest to me were at least 5 feet.

 

Thin-leaved sunflower (Helianthus decapetalus; Asteraceae) is what we call a DYC*; these species can be difficult to distinguish, but this one can be identified by bracts under the flower head that exceed the width of the disk (click on the image to see it larger) and very long, narrow leaf tips (“acuminate” is the technical term). The specific epithet is not to be taken literally; the typical ray floret (“petal”) count is in the range of 8 to 15.

Hairy leafcup (Smallanthus uvedalia; Asteraceae) is another DYC, but this one is easily identified by the gigantic leaves with a unique shape. The few records in Maryland Biodiversity Project are mostly from the Coastal Plain and Piedmont, but a look at the USDA PLANTS Database distribution map makes me think that this species is under-reported. At any rate, I see hairy leafcup in the woods near openings in the canopy, close to the river but rarely in full sunlight. Usually I have to look up to see the flowers (I’m 5’5″ tall).

Here’s another big yellow astery thing: cut-leaved coneflower (Rudbeckia laciniata). The leaves make for easy field ID, but be sure to look at the whole plant; upper leaves are often much simpler in shape.

I was utterly thrilled to find this big, beautiful stand of purple-headed sneezeweed (Helenium flexuosum; Asteraceae) right by the river. Perfect habitat for this species: sunny and wet. How can you not love a flower with a name like that? Pearl crescent butterflies seem to love the flowers, too.

next time: big, showy, pink, purple

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*damn yellow composite

Devastated

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the hotspot, 30 July 2015

“Please rain,” I wrote earlier this year. We got rain, alright. This past May was one of the wettest on record. The Capital Weather Gang reported more than 10 inches of rain in a 23 day period. There was a lot of flooding in the Potomac basin.

Not that I was around to witness it; I was traveling. But the clues are still there: deposits of debris, dried mud on the upslope side of the Billy Goat C trail, muddy tree leaves six feet off the ground, that sort of thing. I saw them this morning when I went out to have a look at my favorite bedrock terrace, which I call the hotspot.

the hotspot pond, 10 June 2015; note how lush, with arrowhead in the water

My usual path to it, across a narrow channel, was still underwater, so I went to another low spot and was able to get across via an islet.

The islet was almost empty: only a few plants, maybe a foot tall coming up through the freshly deposited dirt, no more than one plant per square meter. Big piles of woody material, downed trees, shrubs, and vines on the upstream side of boulders and large trees. Lumber. Plastic and glass bottles. A child’s flip-flop shoe.

jimsonweed on the islet, 10 July 2014

I’ve never gone through that area because by this time of year, it’s waist-high or taller in jimson weed.

the hotspot, 30 June 2016, with a bit of the pond in the foreground

The hotspot was almost empty, too. A few nodding onion on the higher rocks. Racemose goldenrod starting to grow. One small clump of big bluestem grass blooming. Remnants of trumpet creeper and poison ivy. A few scraggly shrubs that might be buttonbush. Very little else.

One of the delights of the hotspot is a pond that’s tucked into the rocks, well above the river. The pond supports aquatic plants, and wetland obligates grow next to it. This year, that little pond held more water than I’ve ever seen in it, but nothing green. The rocky edges were crusted in dried mud. No plants.

the hotspot, 18 July 2017; note how low the water in the pond is, but the area is still lush; zoom in to see flowers on buttonbush and milkweed

Last July in that area I saw flowers on buttonbush, wild potato vine, swamp milkweed, Carolina horsenettle, water willow, thin-leaved sunflower, swamp candles, common arrowhead, fogfruit, and nodding onion. Seedpods on wild blue indigo, and buds on Culver’s root. Halberd-leaved rose mallow taller than me and budding up. Same with joe-pye weed. And cardinal flower. And leafcup and cut-leaved coneflower. Honeyvine climbing over everything, not yet blooming. There was a middle-height forb I identified later as Ludwigia decurrens, the first report of this species in Montgomery County.

This year, on the riverbanks near the hotspot the rosemallows are starting to regrow. Leafcup, coneflower, and sunflower are as well, but they’re only about a foot tall. There’s some water willow in the river. I couldn’t find a trace of any of the other plants: no joe-pye weed or wild blue indigo or Culver’s root or cardinal flower. No honeyvine.

I’m devastated. I won’t get to see those nifty flowers this year.

the hotspot and pond, 3 July 2018

The hotspot, however, was not devastated. This sort of flooding is part of the natural rhythm of the Potomac; the river’s occasional scouring of the bedrock terraces is one of the factors that allows unusual plants, and unusual plant communities, to thrive there. I have no doubt that all the species I mentioned above will be back next year (unless it floods again), in all their glory. And maybe the river will have brought something new.

check the archives for July, 2017, for pictures of plants growing in the hotspot: Golden Glow, Bewitched by Buttonbush, Common Arrowhead, and Ribbet

Please Rain; More Spring Ephemerals

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River levels have been pretty high, and the vernal ponds are more full than I’ve seen them in several years, but I suspect the groundwater level is still pretty low. We need rain.

Or it may be that I need rain. With this compressed season, I’ve been out almost every day shooting, which means I have a backlog of several hundred photos to process and many ideas for blog posts to write. But those things won’t happen until the weather forces me to stay inside.

Micranthes virginiana (early saxifrage)

The initial tide of spring ephemerals is ebbing: while early saxifrage, golden ragwort, and toadshade are near their peak, Virginia bluebells, toothworts, Dutchman’s breeches and squirrel corn are all past theirs, and it looks like bloodroot, trout lily, and harbinger of spring are done. Round-lobe hepatica seems to be done near the Potomac, but is still going strong up at Rachel Carson Conservation Park.

Obolaria virginica (pennywort)

And speaking of RCCP, pennywort is blooming there now, and the pinxter azaleas are well in bud.

 

 

The second wave of spring flowers is well under way in the greater Carderock area.

Houstonia caerulea (azure bluets)

Recently I’ve spotted blue, yellow, and white violet species, sessile bellwort, yellow corydalis, azure bluets, and wild pinks.

 

 

Phlox divaricata (wild blue phlox)

 

 

Wild blue phlox is close to peak, and so is rue anemone.

 

 

 

 

Geranium maculatum (wild geranium)

Dwarf cinquefoil, plantain-leaved pussytoes, wild geranium, and jack-in-the-pulpit are blooming.

 

 

 

 

Cercis canadensis (redbud)

Trees are blooming, too. Redbud flowers are open, pawpaw buds are swelling.

 

 

Dogwood is just getting started.

 

Cornus florida (flowering dogwood)

Other species to watch for: early meadow rue, star chickweed, lyre-leaved rockcress, smooth rockcress…

 

 

 

…and always spring beauties.

Claytonia virginica (spring beauty) growing in an exposed tree root

Winter Blues

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Virginia bluebells carpeting a Potomac River floodplain last spring

Happy new year! I’m back, after a truly epic case of writer’s block. Not that there’s anything blooming to write about yet, since the local wildflower show won’t be starting until late February at the earliest, more likely mid-March if this winter stays as cold as it has been. Which has been pretty darn cold compared to the last five years or so, but not that unusual compared to, say, the past 50 years.

At any rate I’m fighting the winter blues by recalling blue flowers I found this past year. Here are a few from the Maryland Piedmont.

Anemone americana (formerly Hepatica nobilis var obtusa; round-lobed hepatica; Ranunculaceae)
This species is hibernal – the basal rosette of leaves will be out right now, though likely hidden under leaf litter. The leaves will die back as the small flowers appear just an inch or two off the ground. In the Piedmont I’ve seen them as early as early March and as late as mid April, though they don’t bloom for long; they just seem highly variable about when they start blooming.

Baptisia australis (wild blue indigo; Fabaceae)
This species is found primarily in prairies, but also occurs in some prairie-like habitats east of the Appalachians, including bedrock terraces in the Potomac gorge. According to the Maryland DNR’s new RTE list, there are only a few populations here. It’s listed S2/Threatened. Finding it is a real treat.

Clitoria mariana (Atlantic pigeonwings, butterfly pea; Fabaceae)
I’ve only seen this in a few places, always in rocky areas in a bit of shade, and there’s never much of it. Start looking in mid June.

 

 

Conoclinium coelestinum (formerly Eupatorium coelestinum; blue mistflower; Asteraceae)
This medium-height plant blooms from June through September in wet soils next to the Potomac River – not right on the banks, but close by.

 

Houstonia caeulea (azure bluet, little bluet, Quaker ladies; Rubiaceae)
These tiny flowers bloom en masse in April and May in moist, rocky soils in open wooded areas. Sometimes you’ll see only a few, but other times you may find them carpeting a meadow. They are really tricky to photograph up close, as even the slightest breeze sets them in motion.

Ionactis linariifolia (formerly Aster linariifolius; flax-leaved aster; Asteraceae)
I’ve seen this species blooming in a rocky meadow in the Carderock area in October of the last few years, but also in open, rocky areas of the Billy Goat A trail – in June!

 

Iris species, either I. versicolor or I. virginica (northern blue flag or southern blue flag; Iridaceae)
These flowers drove me nuts in 2017. I posted many times about my quest to determine exactly which species it is. There are scattered stands along and near the C&O Canal from the Marsden Tract upstream to Widewater; look for it in late May or early June.

Lobelia siphilitica (great blue lobelia; Campanulaceae) stands dramatically tall on riverbanks. I’ve seen two stands of them along the Potomac: one just upriver of the American Legion bridge, the other near Fletcher’s Boathouse in DC.

 

Mertensia virginica (Virginia bluebells; Boraginaceae)
This spring ephemeral often grows in large swaths in floodplains, like in the lead-in photo above. The pink buds start turning blue as they open. This species can also flower in pure white, pure pink, and pale violet; I love hunting for these variations every April.

Phacelia covillei (Coville’s phacelia, buttercup scorpionweed; Boraginaceae)
A short annual plant with tiny flowers that have to be seen up close to be appreciated. Currently listed S2/Endangered by the Maryland DNR, with a proposed change of status to Threatened.

Phacelia dubia (small-flowered phacelia or scorpionweed; Boraginaceae)
A fellow botanerd directed me to a large stand of this species last spring. Most of those flowers appeared white, but up close a few had this pale blue cast.

 

Phacelia purshii (fringed phacelia, Miami mist; Boraginaceae)
Listed S3 in Maryland. I’ve found only three stands of it between the Potomac and the Billy Goat B and C trails.

 

Scutellaria elliptica (hairy skullcap; Lamiaceae)
Look for sparse stands of these from Carderock to the Marsden Tract, in rocky soils where the woods aren’t too dense.

 

 

Tradescantia virginiana (Virginia spiderwort; Commelinaceae)
In some lighting situations this flower looks more purple than blue, but oh well. I’ll cover purple flowers in a future post. The plant has iris-like foliage: broad blades with parallel veins. The three-petaled flowers are another clue that this plant is a monocot. Which gives me an idea for another future post.