A Pepperweed Adventure

We ventured forth to Bergen Park on a lethal quest, with murder in our hearts. I was to be introduced to a new weed for our area, one that was infringing on the edge of parkland. Clearly it had to go.

Happily for me, though, Perennial Pepperweed (Lepidium latifolium) was not the only plant we encountered that day. Here the pepperweed, which was not yet blooming, consorts with Poison Hemlock (Conium maculatum), another exotic, in full flower.

This post doesn't qualify for Plant of the Week; perhaps I should call it a "plant of last month." Late July and most of August were absorbed, it seems, in the wink of an eye! Forgive me for taking you back to early July for this little botanical adventure.

The first few plants we uprooted seemed innocuous enough, but I latched on to one, near the base of a small ponderosa pine, that soon delivered an extensive root system. Perhaps the mother of all pepperweeds...

According to one reliable source,

"Perennial pepperweed is a highly invasive herbaceous perennial. It can invade a wide range of habitats including riparian areas, wetlands, marshes, and floodplains. It adapts readily to natural and disturbed wetlands. As it establishes and expands, the plants create large monospecific stands that displace native plants and animals."

So far so bad. The good news is that, in the course of an hour or so, the two of us seriously depredated this patch of pepperweed, leaving few, if any, survivors above ground to reproduce. The bad news is: it's perennial. As we wandered the area, looking for any surviving remnants, we noticed an odd distribution pattern: it seemed to be associated with the pines. Here it also shows a bit of a zonation pattern, with hemlock behind, pepperweed next to the pine, and smooth brome in the foreground. Lovely.

Clearly we were not in a pristine ecosystem by any means. This is a park that is rapidly gentrifying, and has been used for almost a century. We were also right next to a "park and ride" for the local bus system. In beautifying the area around their new parking lot they had, logically, planted "native" ponderosa pines from a local nursery. (Though why they didn't use the many native pine seedlings on site, I can't explain.) We speculated that the source of the infestation was the root balls of these imported trees. Upon being informed of its presence, the bus company promptly mowed the entire area. Problem solved, right? Well, maybe...

The Park Service (source above) adds:

"Application of the control plan must be repeated numerous times to obtain lasting management.... Sources of infestations should also be located and eliminated to prevent future infestations.... Mechanical control options are typically not effective. Very small patches can be controlled by hand removal if the process is repeated often for several years and plants are not allowed to mature."

Looks like we have our work cut out for us. We have a chance, with conscientious monitoring at this site, to prevent this weed from gaining a foothold that will overwhelm our ability to deal with it in the future. It's early, here, for this one. Perhaps we won a battle, but vigilance, eternal vigilance, is the key in this war. Fortunately, some of our aggressive invaders are not so intractable.

Here's the meadow at Bergen, looking back into the park (a ponderosa pine grove). The brown seedheads of a Smooth Brome monoculture are distinct, enabling its immediate recognition. Most of us live, around here, in a world of mountain meadows dominated by Smooth Brome (Bromus inermis), which was deliberately introduced to the United States and Canada in 1880 from Hungary and in 1896 from Russia. It is still being actively recommended as a pasture grass.

As we moved away from ground zero of the pepperweed infestation, thankfully, more welcome denizens of a montane meadow began to assert themselves. To my surprise, there were harebells (Campanula rotundifolia) still in bloom (long gone at my home elevation), blanket flowers (Gaillardia aristata), and more. I might have gotten more photos, but the presence of a favorite mountain grass thoroughly distracted me.

Parry Oatgrass, Danthonia parryi, is not only elegant, graceful, beautiful, and native, but distinctive and, thus, recognizable! (Always a desirable quality in grasses.) This year, with 3 more inches (7.6 cm) of rain than usual, I've been noticing it everywhere. I can only conclude I'd overlooked it before; I'd thought of it as somewhat rare, or at least unusual. I like it so much I once obliquely featured it in an article, and even put the illustration of it on my business card.

Here's what I didn't know about this intriguing grass: it is reported only from four states (MT, WY, CO, and NM) and two provinces (ALB and SASK). In other words, straight down the spine of the Rockies, primarily on the eastern side. It is secure in Alberta, according to NatureServe, and imperilled in Wyoming; other areas have not been assessed. Within Colorado, its distribution is a bit irregular, most likely due to inadequate collections. Parry Oatgrass is, for example, not reported from our county, where this site (the red triangle) is.

Although they're surrounded by Parry Oatgrass, especially this year, I suspect that few mountain residents would recognize this grass under any circumstances. Here it shares the foreground with harebells and other wildflowers, as is proper, but smooth brome lurks in the background. Even long-time mountain residents think they see pristine landscapes where, in fact, they are seeing agriculture.

——
Perennial pepperweed, according to the USDA Plants Database, has been introduced in about 20 states of the U.S. and six Canadian provinces. It is native to southeastern Europe and southwestern Asia and, according to the Park Service, "probably entered the U.S. prior to 1940 in a shipment of beet seed (Beta vulgaris) from Europe." In Colorado it is a "List B" exotic weed. Smooth Brome, however, is still being planted.

——
Submitted for edition #20 of the plant carnival, Berry-Go-Round.

Expecting the Unexpected

To some extent, a foothills canyon is a familiar, known entity. Delightful to explore, but rarely yielding surprises. Or maybe I’ve just been spending too much time in the lower elevations. But last summer’s visits to a hidden gulch just 2,000 ft (610 m) higher than my usual whereabouts brought new discoveries for me, and seemed a rare treat even to the more experienced botanists I took along on future visits. Everyone got excited about this place!

First, that fern. It was everywhere here in the gulch, but I had never encountered it elsewhere. Patience for keying is never my strong suit, but this little guy fell out indisputably at the 4th fern couplet, without a hand lens. That's my kind of fern! My real botanist friends later confirmed the identification. Among Colorado’s modest fern flora it is exceptionally recognizable. The Northern Oak Fern (Gymnocarpium dryopteris) is reasonably rare in Colorado. It had been reported from one locale in my county, but never from this nearby county.

Here's a close-up, courtesy of Priscilla, of those beautiful sori that cinched the ID, if we could have been mistaken before. The fact that they are naked, lacking indusia, and not marginal, separates this from, guess what?, Bracken Fern (Pteridium aquilinum), just in case its delicacy and grace were not enough to distinguish the two.

With a substantial surprise like that right at the start, we began to expect the unusual. Sure enough, more surprises awaited around every twist in the gulch. One after another, plants that were doing quite well here, thank you. I guessed many of these moisture lovers, including my little fern, would be more familiar to readers of eastern North America than they are to me. I may have been wrong.

Let’s start with the wintergreens, all low ground covers with attractive flowers.

Single Delight (Moneses uniflora, Pyrolaceae)
Tiny and shy, this little wintergreen is pretty well established in appropriate parts of Colorado, that is, moist subalpine forests from 8,000 to 11,800 feet (2440-3600 m). It is, however, threatened or endangered in Connecticut, Ohio, and Rhode Island, although it does better in New England and is secure in Canada. You have to make a real effort to see its flower-face, always cast downward and held barely an inch above the ground.

One-sided Pyrola (Pyrola secunda, Orthilia secunda, Pyrolaceae)
Just slightly taller than Moneses is this related species, but its flowers are clustered at the top of their stalk. Widely distributed in mountainous western Colorado from 8200 to 13,000 feet (2500-4000 m), it has been found as low as 7000 ft (2130 m) in exceptional situations. But it seems to be losing ground in the east: strong across southern Canada, as well as in New England and New York, it is threatened or endangered south of about Pennsylvania. It was historically reported as far south as Virginia.

Pink Wintergreen (Pyrola asarifolia, Pyrola rotundifolia var. asarifolia, Pyrolaceae)
Similar story here: threatened or endangered, according to some sources,* in Indiana, Iowa, New York, Vermont, and New Hampshire, secure and broadly distributed in southern Canada.

Many more of our discoveries await description: the orchids I failed to capture in photos and those that we were too late to see at all but suspect are there. All the "berries": bunchberry, baneberry, cranberry (sort of)... And of course the special lichens and mosses and liverworts. An entire post will have to be devoted to the fungi. This gulch will feed my foothills fancies for a long time.

All of these plants have a circumboreal distribution. Not in the far north (boreal or arctic), but as close to it as they can comfortably get. In effect, our hidden gulch was in a small peninsula of the Canadian forest, extending down the Rocky Mountains into and through Colorado. When we find these special plants, we recognize them as fringe species, far from home at the edge of their range, hanging on in small patches of cool, mesic habitat wherever possible. They occupy a narrow coastline in a habitat no longer characteristic of Colorado.

There’s a small picture here: this one tiny gulch, about a half-mile (1 km) long and a few hundred yards or meters wide. On this scale, our gulch seems to be a little piece of Subalpine Forest transported downslope, thanks to the cool north-facing slope and the narrowness of the shadowed defile. There was some Englemann Spruce (Picea englemannii), but the co-dominant Subalpine Fir (Abies lasiocarpa seemed to be missing. (This year, I'll search the overstory more carefully.)

But there’s also a larger picture: an image of glaciers flowing across a continent and down from mountain peaks, figuratively pushing a host of plants and animals ahead of the ice and cold. The glaciers have retreated, and the plants follow their favored habitat. The unsettled or alarmed status these plants are given in many states reflects a readjustment on a continental scale, telling us we’re no longer in the Pleistocene. A process underway for the last 10,000 years, this geographic adjustment will be only more visible, more accelerated, in the decades ahead. How much longer will we be able to find these unexpected treasures?

What one finds... will be what one takes the trouble to look for.
—Joseph Wood Krutch

——
This and the preceding post are submissions for the plant carnival Berry-Go-Round; edition #2 to be hosted soon at Further Thoughts.

*Explore plant distributions by typing in species names at the USDA Plants Database or at NatureServe. Note that the status categories don't always match, or exactly reflect state records, and they can also vary by subspecies.