Compressed (part 2)

Here are some of the showier spring ephemerals to watch for in the Potomac Gorge this week.

In the floodplain close to the river, Virginia bluebells (Mertensia virginica; left) are approaching peak bloom. Mixed in with them in a few places are Dutchman’s breeches (Dicentra cucullaria; below right), which you might also find on moist, rocky outcroppings.

Trout lilies (Erythronium americanum; above left) like moist soils, too. Generally I see them in the transition areas between floodplain and slopes.

Further upslope are cut-leaf toothworts (Cardamine concatenata; left).

 

On drier slopes watch for scattered patches of bloodroot (Sanguinaria canadensis; below).

 

 

Look for twinleaf (Jeffersonia diphylla; below) in moist, rocky areas. They like limestone soils, so aren’t as widespread as these other species, but where they do grow they they tend to grow en masse.

Spring beauties (Claytonia virginica; below) are just about everywhere.

 

 

 

 

More tomorrow.

Compressed

Friday afternoon I met two entomologists on the trail. “Everything’s all stacked up,” they said, meaning the bugs are all coming out at the same time. It’s pretty much what I’d been thinking about the wildflowers, because they’re doing the same thing: opening all at once, rushing into spring as soon as Persephone flings open the doors.

Of course it got cold again today, but yesterday, once the sun came out and temperatures rose into the 60s, the show was extraordinary. I expect it will be again tomorrow, and any other warm, sunshiny day in the coming week.

This was in the Potomac Gorge, of course. I have no idea how long the flowering will last. Get out there soon. Details and pictures tomorrow or Monday, as soon as I have time.

Alien ≠ Invasive

As the weather warms and wildflowers and weeds start emerging, and gardeners and botanerds start talking about the coming growing season, words get tossed around and, sometimes, misused.

Not long after I finished writing the post about the word native, the very topic of “alien invasives” came up in a forum I moderate. The topic was dandelions. Are they alien invasives?

It’s important to understand that although those two words are often used together, “alien” and “invasive” are two different concepts. “Alien”, like “native”, refers to origin, while “invasive” refers to growth habit.

Yes, dandelions are alien in North America. But they are not necessarily invasive.  Here are some legal definitions:

‘‘Alien species’’ means, with respect to a particular ecosystem, any species… that is not native to that ecosystem….‘‘Invasive species’’ means an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health

National Environmental Policy Act, 42 USC § 4321

Note that by definition, invasive species are aliens, but it is not necessarily true that alien species are invasive.

Vinca minor (periwinkle), alien and invasive; please don’t plant it

So we often ask ourselves: is it ever okay to grow aliens? I believe the answer is yes, so long as they aren’t invasive aliens. Remember: first, do no harm. If you’re considering planting an alien or naturalized species, or even a species that’s native to some place nearby, do a little research. I would have no qualms about planting Baptisia australis, but I’ve removed Stylophorum diphyllum from my garden, because I see it spreading pretty aggressively in nearby woods. (See Nativity and Granularity)

Also, consider this statement from invasive.org:

…it is nearly impossible to predict which species will become invasive and new species are being introduced every day. Some species are present for many years before they exhibit invasive characteristics. Many invasive species go through a “lag phase” in which their populations grow slowly until they reach a size large enough for the population to explode and/or become adapted to the local environment and become invasive.

The responsible gardener keeps her eyes and ears open, and promptly removes anything that’s been re-classified as invasive (as I did a few years ago with Nandina domestica).

Galanthus nivalis (snowdrops); obviously naturalized but not yet dubbed invasive

This issue of invasive aliens gets complicated. Since I am definitely not an expert, I’ve complied a list for further reading. If you’re a gardener, pay special attention to your local and state laws regarding problem species, like Maryland’s new regulations about the sale of invasive plants.

 

 

Invasive Species 101  -Center for Invasive Species and Ecosystem Health
Mistaken Identity – Invasive Plants and Their Native Look-Alikes, Delaware Department of Agriculture
What Are Invasive Plants? -Virginia Department of Conservation and Recreation
The Problem with Invasive Plants -City of Portland, Oregon Environmental Services
Invasive Species: What You Can Do -The Nature Conservancy
Frequently Asked Question About Invasive Species -US Fish and Wildlife Service
Compilation of Regional Invasive Plant Species Lists  -University of Maryland Cooperative Extension

-with thanks to Kerry for pointing me at several publications

If There’s One, Maybe There Are More

Some of our spring ephemerals are large and showy, like Virginia bluebells. Some are smaller yet also showy, like trout lily. But many are quite small, and not showy at all, unless you see them up close and en masse.

That’s the case with round-lobe hepatica (Anemone americana, formerly Hepatica nobilis var. obtusa; Ranunculaceae).

Last Thursday, I walked over to the area where I photographed a single clump of these flowers a month ago. All by themselves like this, they really stand out. That’s not usually the case, though. These little charmers love to hide in the leaf litter.

this is an unusually open location (click to enlarge and see the flowers)

I’d heard rumors that there were more to be found in that area, so I spent a long time walking slowly and looking for anything colorful. As my eyes acclimated I started seeing them – first one, then another and another. In an area where I thought there was only one plant, there were a dozen.

Check out the variation in color. I did minimal processing of these photos in order to preserve the range of color, from dark blue to pure white.

All these plants were putting up just a few flowers. The clump pictured in the first three photos is unusually large and robust, and showier since it’s growing in an open area.

In this photo to the right you can see a few leaves below the white blossoms. Round-lobe hepatica is hibernal, meaning the leaves grow in the summer and stay through autumn and winter, dying back in the spring as the plant blooms.

The flowers pictured below are a very pale blue.

Round-lobe hepatica is one of the first plants to bloom in the spring; it can be found in most of Maryland except for part of the coastal plain. Look for it now on wooded slopes where the soil is relatively dry.(I’ll get back to the whole native/alien thing soon, really.)

But First, a Quick Update

I went scouting on the Billy Goat C Trail Monday. Harbinger -of-spring is still blooming. More spring beauties are blooming.

Just a few Dutchman’s breeches are open.

 

 

 

 

As are cut-leaf toothwort.

 

 

 

 

And just a few golden ragwort.

 

 

 

 

Virginia bluebells are budding up nicely. A few more days of warm weather and the ephemerals show will be underway.

Nativity and Granularity

I’m fascinated by words, their sounds, their rhythms, their meanings. By semantics. Mostly I try not to be pedantic about words, but when the subject is “native” plants, I have to be.

It’s a word and concept that comes up all the time for us botanerds. Like asking if the newborn baby is a girl or a boy, nativity is where our understanding and appreciation of a plant starts.

But why? Why do we care, and what does it really mean, anyway?

Merriam-Webster defines “native” as “living or growing naturally in a particular region”. The USDA offers a more specific definition:

A plant that is a part of the balance of nature that has developed over hundreds or thousands of years in a particular region or ecosystem. Note: The word native should always be used with a geographic qualifier (that is, native to New England [for example]). Only plants found in this country before European settlement are considered to be native to the United States.*1  [emphasis mine]

In an online forum the topic recently came up, with respect to wood poppy (Stylophorum diphyllum, pictured above). Have a look at the USDA PLANTS Database distribution map for it:

The map implies that wood poppy is native to Maryland. Now have a look at the county-level map (same page, zoomed in):

This map shows wood poppy present somewhere in the state of Maryland (the light green color means that there are no county-level records). Note that other than in Maryland, there are only two locations east of the Appalachians where wood poppy is present: southeastern Pennsylvania and the District of Columbia. Considering the rest of the distribution, it doesn’t really make sense that there are “naturally occurring” populations of this species outside the mid-west.

Various sources I’ve checked agree that wood poppy is not native to Maryland. According to Alan Weakley, wood poppy is found in

Moist forests over calcareous rocks (such as limestone). Mar-Jun. S. QU, w. PA, s. MI, and WI, south to sw. VA, e. TN, nw. GA, sc. TN, and AR; introduced elsewhere from horticultural use. [= C, F, FNA, G, K, Mo, Pa, S, Va, W, WV] *2    [emphasis mine]

This is not to say that the USDA PLANTS Database is untrustworthy. It’s an excellent source of good information. My point here is that without the right qualifier, it’s useless to ask if a plant is native. In this example, it’s correct to say that S. diphyllum is native to North America, and it’s correct to say that it’s native to the lower 48 states, but neither of these statements implies that the species is native in every wild place it’s found.

Since wood poppy is not native to Maryland, but is found growing wild here, we need a word other than “native” to describe it. “Alien” would be technically correct but that word is loaded with negative connotations. The correct term is naturalized.

Getting back to that idea of geographic qualifiers, it’s possible to go a little crazy when you’re trying to decide if something is native. Consider Baptisia australis (wild blue indigo), which has a scattered distribution in the eastern US. In Maryland it is known in only a few locations along the Potomac River, including the Potomac Gorge. So if I were being utterly ecologically correct, I wouldn’t grow it in my garden, because my garden isn’t in the Gorge; it’s about a quarter mile away at a different altitude and on a different underlying rock formation.

But that is a ridiculous level of granularity. If I’m trying to build a showcase garden of Maryland native wildflowers, should I exclude these two species because the one is naturalized and the other grows only in very specific locations?

The answer to that question consider the maxim “first, do no harm.” More on that next time.


*1Natural Resources Conservation Service
*2Flora of the Southern and Mid-Atlantic States, page 465

maps from USDA, NRCS. 2018. The PLANTS Database (http://plants.usda.gov, 19 February 2018). National Plant Data Team, Greensboro, NC 27401-4901 USA.

Braking for Wildflowers Again


Steve and I were in Joshua Tree National Park recently. There wasn’t a super bloom this year, but there were still a few wildflowers. Mostly they were the Sonoran and Mojave desert plants that I wrote about this time last year, and the year before that.

Heading south on Pinto Basin Road toward the Cholla Garden, I spotted large, dark green leaves on plants growing by the side of the road. What the heck, is that datura? I thought. Then, “Steve, slow down!”

And he did, and pulled over, and I jumped out and had a look.

Yes, they were Datura, but all the flowers were spent or closed. So the next day we went back, and drove slowly (whenever no cars were behind) until I spotted some open flowers. And he pulled over again, and had a little catnap in the car while I got on my belly on the sandy roadside shoulder and snapped some pictures.


There are two species of datura in JOTR, D. wrightii (sacred thorn-apple) and D. discolor (desert thorn-apple). This one is the former. Other common names for the various Datura species include jimsonweed and angel’s trumpet; there are dozens more, including moon lily, moon flower, belladonna, devil’s trumpet, deadly nightshade, thorn apple, mad apple, hairy jimson weed, stink weed, green dragon and locoweed1, and toluaca2.

These spectacular flowers measure about 15 cm long, and the plants can grow to a meter or more tall and almost two meters wide. All parts of the plants are poisonous, not unusual for plants in the Solanaceae.

The Solanaceae, like the Apiaceae (see Tasty Umbellifers and Poisonous Umbellifers), is notable for producing both foods (eg, tomato, potato, chili pepper, and eggplant) and poisons (eg, belladonna, tobacco, mandrake, and henbane).

We have a datura here in the Maryland piedmont, D. stramonium [right], but it’s an invasive alien that can form large, nearly monocultural stands. There’s an especially bad infestation on an islet in the Potomac just upstream of the American Legion bridge [below].


1DesertUSA
2Calflora