Continuing with pretty pictures during this cold season. It’s a thin line between blue and purple. Color is a continuum. Color is in the eye of the beholder. If some of these look more blue or pink than purple, well, c’est la vie.

Triodanis perfoliata (Venus’ looking glass; Campanulaceae)

Look for this annual forb growing in rocky places where there isn’t much competition from other plants. It generally blooms from about mid May into early June here in the Maryland piedmont.

Clinopodium vulgare (wild basil; Lamiaceae)

A perennial forb with circumboreal distribution. Look for the flowers in the height of summer.



Cunila origanoides (common dittany; Lamiaceae)

A perennial native to North America, and found mostly in the mid West and mid Atlantic. It blooms in late summer.


Elephantopus caroliniana (Carolina elephant’s foot; Asteraceae)

A rather weedy-looking plant with a fascinating inflorescence. Click on the picture and look closely; you’ll see that this is actually four disk flowers, each with a five-lobed corolla. The species is native to the southeastern US (Maryland is almost as far north as it goes). It blooms in late summer.


Eutrochium purpureum (sweet joe-pye weed; Asteraceae).

The joe-pye weeds (formerly Eupatorium species) are perennials that love wet places, but this particular species tolerates drier soils and is a great native for the home garden, with dramatic heads of colorful flowers towering above most other forbs. And it attracts butterflies. Blooms in late summer.

Mentha arvensis (field mint; Lamiaceae)

Another mint-family plant with circumboreal distribution. Another late-summer bloomer.



Mimulus alatus (winged monkeyflower; Phrymaceae)

Watch for this wetland plant and its almost identical cousin M. ringens var. ringens (Allegheny monkeyflower) blooming in early to mid summer.


Monarda fistulosa (wild bergamot; Lamiaceae)

The mint family sure is represented well here. Look for it in mid summer, possibly covered in bees and butterflies.


Phlox divaricata (woodland phlox, wild blue phlox; Polemoniaceae)

As you can see this flower ranges from almost white through lighter and stronger shades of blue and purple. They bloom at about the same time as Virginia bluebells. Bluebells grow in the floodplain while this phlox grows just upland of the floodplain, in still moist (but not wet) woodland soils.

Physostegia virginiana (obedient plant; Lamiaceae)

Yet another mint family mid summer bloomer. Watch for it on rocky outcrops and gravel bars in the Potomac.





Ruellia caroliniensis (hairy wild petunia; Acanthaceae)

In Maryland this species is found mostly in the Coastal Plain; in the piedmont it’s restricted to a few sites near the Potomac River (as far as I know – please leave a comment if you know otherwise). Watch for it in late spring and early summer.

Trichostema dichotomum (forked bluecurls; Lamiaceae)

Blue or purple, or splitting the difference? Whatever. This is a most striking plant, one of those OMG finds. Well it was for me, anyway. What a lurid color. Late summer, dry soils, open areas. Yow.

Verbena hastata (blue vervain, swamp verbena, Verbenaceae)

As one of the common names suggests, you’ll find this in wetlands, blooming anywhere from late June to mid August. This is an extreme closeup; the plants are rather tall but the inflorescences rather small.



Vernonia noveboracensis (New York ironweed; Asteraceae)

All ray flowers with strongly exserted stigmas, no disk flowers. Very tall plant, wispy appearance. Likes wet soils. Blooms in mid to late summer.


Viola palmata (early blue violet, three-loved violet; Violaceae)

Violet taxonomy is in flux, and violet species can be difficult to differentiate. This one is relatively easy because of the unusual leaf shape, although even that can be highly variable. Look for it in mid spring in drier woodlands.

Water Willow

There’s something refreshing about seeing all these green, grassy-looking plants growing right in the Potomac River every summer. They aren’t grasses, though; they’re water willow (Justicia americana; Acanthaceae), an emergent aquatic whose rhizomes form vast stands of plants in the shallow waters of ponds and streams.

The plants will grow to as much as three feet tall, sending up long stems with tight clusters of flowers on the ends. Only a few stems at a time will bear flowers, but the blooming period of a colony can last two months or more.


Water willow is native to eastern North America, ranging from Texas and the eastern Great Plains northeastward to New York, Ontario, and Quebec. It’s endangered in Iowa and threatened in Michigan.



Of the roughly dozen and a half species of Justicia found in North America, this one is by far the most northern species. One other occurs in the southern part of the Mid-Atlantic, and one in the Mid-West; the rest seem to be found only in Florida, Texas, or the Southwest.

Last spring I found the closely related Justicia californica in Anza-Borrego Desert State Park; it grows as a shrub or tree in the Sonoran and Mojave Deserts.

Hard to believe they’re in the same genus.

Flower of the Day: Hairy Wild Petunia


aka Carolina wild petunia
Ruellia caroliniensis




Despite the common name, and despite appearances, this plant is more closely related to water willow (FotD June 20) than to the common garden petunia.  The latter plant is in the genus Petunia, family Solanaceae, and is therefore closely related to tobacco and tomatoes.

Actually Ruellia and Petunia are quite far apart taxonomically; not only are they in different families,  they’re in different orders (Scrophulariales and Solanales, respectively).

About 15 species of Ruellia can be found in the continental US; of these, four are found in Maryland, and of those four, this is the only one you’re likely to see. The other three are critically imperiled here.


R. caroliniensis ranges from New Jersey (where it’s endangered) west to Illinois, and then south to the Gulf coast.  It grows one to three feet tall.  I’ve seen references to it liking both dry, sandy soils and moist soils; the three places in the Gorge where I know to find it have sandy soils that are prone to minor flooding, so I’m not sure what to make of that.


See the partly submerged rock on the lower right?  Yeah, that’s one of the places where this plant grows.


Flower of the Day: Water-Willow


aka American water-willow
Justicia americana

As spring turns into summer and the water levels in the Potomac drop, the stems and foliage of this aquatic plant appear along the river’s edge, growing out of the water.

20150616-20150616-_DSC0101 Water willow spreads by rhizomes, forming large colonies that help stabilize shorelines and provide habitat for small invertebrates.  Many types of bees, flies, and butterflies feed on the nectar or pollen.  I don’t know if water-willow could properly be considered a keystone species, but it certainly is ecologically important.

Hundreds of species of Justicia grow in tropical and temperate zones of the Americas and parts of Asia and Africa, but only about two dozen are native to the US.  American water-willow is by far the northernmost growing of these species, and can be found as far north as Ontario and Quebec, though no further west than Texas.  It’s threatened in Michigan and endangered in Iowa.

Although each flower is relatively short-lived, and only a few are produced at a time, the overall blooming period of the plant can be several months long.


evening clouds reflected in the Potomac