Parking Lot Edge Wildflowers, Estes Park, Colorado

Particular plant species generally have particular habitats where you will find them. Rainfall, temperature range, shade, soil characteristics and disturbance (level of trampling or grazing or similar effects) determining where a plant thrives and where it does not survive. Thus, if you go looking for flowers, which ones you find depends on where you walk. 

We tend to see the same ones over and over, because they grow well where people walk, liking the sunniness and not minding being stepped on sometimes. Conversely, hikers will likely see quite different plants when they get a mile into the wilderness area

Rocky Mountain forest wildflower
blanket flower, Gaillardia aristida

Consider that if you lived in a mountain cabin, roadside weeds like bindweed (Convolvulus arvensis, morning glory family Convolvulaceae) and Queen Ann's lace, (Daucus carota, carrot family, Apiaceae) would be novel and interesting, while blanketflower (Gaillardia aristida, sunflower family Asteraceae) and columbines (Aquilegia, buttercup family, Ranunculaceae) would not be worth noting. 

miner's candles (Cryptantha virgata)

We hiked trails in Rocky Mountain National Park one day last June, where the flowers I saw included the blanket flower and the miner's candles (Cryptantha virgata, borage family, Boraginaceae) (above). (Forest wild flowers of that trip link). We went to lunch beside Lake Estes, and how cool!, next to the restaurant, the plants were different. 

The photo below shows the location. The sandy access road beside a large parking lot was used a lot, but beside it, the disturbance was less. Fewer people walked or drove over the plants next to the road, and even fewer close to the building. You can see the plants are taller to the right, because they haven't been squashed or broken as often. Furthermore, the stored boat trailers protected the plants under them. The boat trailers appeared to be used regularly but not very often. 

disturbed area by Lake Estes

In response to more and less trampling, the plants were different. And they were certainly not those of Rocky Mountain National Park's forests and meadows. 

Close to the road were very tough plants, tolerant of being flattened by heavy vehicles. This one, with a circle of tiny blue flowers, is probably western stickseed, Lappula occidentalis (borage family, Boraginaceae), native across the Northern Hemisphere in disturbed areas such as this. 

western stickseed, Lappula occidentalis

Another plant there was cheatgrass, also called downy brome, Bromus techtorum (grass family, Poaceae), a spring annual. It is the light brown drooping grass in the photo; it was already dying and going to seed at the end of June. It is a bad weed in the West because it comes up early, absorbs water other plants need, and then dies, forming crispy stands that stick pieces into your socks and aid wildfires. Here, it probably grew well in April and May while tourist traffic was light. 

cheatgrass, Bromus techtorum

Also there was hoary alyssum (Berteroa incana, mustard family, Brassicaceae), the white flower in the photo below. Introduced from Eurasia, this is a plant of trampled areas that abundant enough to be listed as a noxious weed in at least Colorado, Montana, Idaho, California, Oregon, Washington, and Michigan.  (Noxious weeds are plants causing enough damage, usually in crop fields, sometimes to livestock, to warrant states and counties spending money controlling them.) Hoary alyssum is pretty, tough, and too aggressive. 

hoary alyssum Berteroa incana.

Also there, about half way to the building, were young plants of mullein (Verbascum thapsus, figwort family, Scrophulariaceae), another European invasive species. Mullein grows as a rosette of leaves on the ground until it has enough energy to flower. In its second year, it sends up a flowering stalk that can be 6' high. But if the site difficult, like this one, the flower stalk may be only a foot high, with just a few flowers. Flexible responses are important to plants of disturbed areas. 

mullein, Verbascum thapsus

As I stepped closer to the boat trailers, the plants were taller. This is Jim Hill mustard (Sisymbrium altissimum, mustard family, Brassicaceae) about a foot and a half tall (my photo is looking down on it). It is a widespread European weed that is a major noxious weed in the Great Basin, including Colorado. Jim Hill was a Canadian railroad builder of the late 1800s; this plant followed the railroads into central Canada and so people named it after him. It is also called tumble mustard because it tumbleweeds to disperse its seeds. 

Jim Hill mustard, Sisymbrium altissimum

Here you can see the protection provided by the boat trailers. The plant is musk thistle, Carduus nutans (sunflower family, Asteraceae), a European thistle that is a noxious weed in much of the US, including Colorado. It is close to flowering, the top flower head showing color, but a day or two from being open. 

Musk thistle wasn't the only plant that, under the trailers, could grow more than a foot tall. This is one of the knapweeds (Centaurea species, sunflower family, Asteraceae), that are noxious weeds across Colorado. Close to the building, it has grown two feet tall. 

knapweed, Centaurea species

The yellow sweet clover (Melilotus officinalis, pea family, Fabaceae) was also more than a foot tall under the boat trailers. It is a weed from Europe that can turn roadsides yellow in Colorado and Wyoming. As a legume, it puts nitrogen into the soil, so is a "better" weed than most others, but still gets way too abundant. 

yellow sweetclover, Melilotus officinalis

This one, looking a lot like yellow sweetclover in my photo, is in fact curly dock (Rumex crispus polygonum family, Polygonaceae). The yellowish tops are developing seeds, not flowers. Like others under the trailers, they have grown two feet high protected from trampling. From Eurasia, curly dock may have been brought to North America as medicine or food. It has escaped and is found all over the continent, reaching noxious weed status in at least Iowa, Arkansas, Michigan, Minnesota, and Indiana. 

Rumex crispus, curly dock

But also under the boat trailers were two natives, an evening primrose and a penstemon. 

Evening primroses (Oenothera, evening primrose family, Onagraceae) are native wildflowers, the genus native only to the Americas. There are about 85-95 species native to North America (see USDA data base) found all over the continent. The common evening primrose, Oenothera biennis is more widespread than most of the evening primroses, found in most states, and grown in Europe as a vegetable where it has escaped as a weed. So I thought this was common evening primrose, but Ackerfield, in the 2nd edition of Flora of Colorado, says all the specimens of common evening primrose collected in Colorado that she has seen are really hairy evening primrose, Oenothera villosa. And if you look at the USDA map, it does not show common evening primrose in Colorado. Hairy evening primrose is enough like common evening primrose to fool plant-collecting botanists! It is a biennial or short-lived perennial, and, because this one is flowering energetically, it has likely grown here for at least two years. The flowers are yellow and open in the evening.

evening primrose soon to flower;
probably hairy evening primrose Oenothera villosa

And here is a penstemon, genus Penstemon (plantain family, Plantaginaceae), also called beardtongue as a common name. Penstemons are native to the Americas (only) and there are about 280 species. In Colorado there are more than 60 species, about half of them with blue flowers, so I can't identify this to species. But it very much counts as a native wildflower growing under the boat trailers. As does the evening primrose, so this somewhat protected area beside the building supports not just aggressive Eurasian plants but native wildflowers. 

beardtongue, Penstemon

It was fun looking at the plants of this weedy area between the access road to the lake and the lake-side restaurant, because not only were the plants quite different from in the meadows of Rocky Mountain National Park a few miles away, there were distinct zones within this little band of plants. The noxious weeds are common in disturbed areas, like roadsides, but are often restricted to those conditions, so you do not see them where plants can get taller or in native plant communities. Plants have habitat requirements and are not found everywhere. 

Happy spring wildflower spotting!

Comments and corrections welcome

Notes

I included plant family names even though they are intrusive because the families are much more widespread than particular species; you might know the mustard family even if you have never heard of hoary cress, Berteroa incana. It also let me see that how diverse the plants I saw were, the tough weeds are diverse, from several plant families, not just one, for example. (My blog on "Why do botanists always tell you the plant family?" link)

Also, I want to repeat that identification is only as good as the resources you have. Apple's Photos ap offered me names for these plants and in several cases, it was wrong, so I spent many minutes figuring that out and getting a better name. In particular, I check against the geographic distribution of the plant, looking at the USDA's plant data base plants.usda.gov or  the Invasive Plant Atlast (link) or Flora of Colorado or the Flora of North America (link) In Colorado, beyond just "has it been reported for this county?" one can ask "is it known from this elevation?" When the distribution doesn't match, probably the i.d. is wrong. 

References/Resources

Ackerfield, J. 2022. Flora of Colorado. 2nd ed. BRIT Press,  Fort Worth,Texas. 

Noack, R., M. Pokorny, J. Jacobs, and J. Mangold. 2020. Plant Guide for hoary alyssum (Berteroa incana). USDA-Natural Resources Conservation Service, Bridger Plant Materials Center, Bridger, MT 59014. link

Plants for a Future. No date given. Rumex crispus. link (a useful-plant site, this doesn't address it as a very common invasive in North America.)

U.S. Forest Service. No date given. Melilotus alba, Melilotus officinalis Fire Effects Information Service (FEIS)  link

U.S. Forest Service. No date given. Sisymbrium altissimum Fire Effects Information Service (FEIS) link

Kathy Keeler

A Wandering Botanist

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