One is continually surprised by how many new plants are coming into bloom: in high meadows, along wetlands, sage flats, and roadside edges. Many of them are “composites” or members of the aster, daisy, or sunflower family: Asteraceae. Many are yellow, others- mostly “asters”- are blue, and some you may not know are in bloom at all: sagebrushes. A few other unrelated odd species pop up as well, such as elegant gentians and inelegant broomrape. Below are a few wildflowers that you might notice on your hikes and drives around the valley. Plus a quiz plant!
Western Coneflower– Rudbeckia occidentalis – The purplish brown cone-shaped receptacle never looks quite in bloom until you notice the bees working them over.
Looking closely, you may see a row or two of tiny “disc” flowers with pollen being pushed up. They start blooming at the base and gradually continue row by row up to the tip. These 5’ plants with large 6-8”, rough, oval leaves are found in moist meadows.
Curly Cup Gumweed – Grindelia squarrosa – A relative newcomer to Jackson Hole from its surrounding native range, it has now migrated in along dry roadside edges, mostly in the south end of the valley. Look carefully at the bases of each head to see the distinctive bracts curling back from the center.
These one-of-a kind heads are very resinous: sticky and pungent. The 1” leaves are toothed, and often clasp the stems. Sage grouse chicks 5-8 weeks old relish gumweed in Montana, and maybe here as well?
Showy Goldeneye – Viguiria multiflora – Also found along roadsides and trails in the sun to partial shade, these cheerful 1-3’ high plants catch your eye. Flowers are borne loosely atop wiry stems.
The 2”-3” long, neat, oval leaves with pinnate veins are held opposite each other. The flower heads are surrounded by tidy rounded bracts, and you may notice the 8-10, broad, petal-like ray flowers are slightly darker toward the center. In bee vision, this slight change in hue creates a bull’s-eye pattern. Pollinators have a perfect landing pad from which to gather nectar and honey.
Parry’s/Rayless Arnica – Arnica parryi – This odd-ball arnica grows 1-2’ tall on the edges of high meadows and coniferous forests. Unlike its sunflower-like cousins, this species has rusty yellow flower heads with disc flowers only bunched together in 1” heads. However, the bracts beneath are all the same size; the leaves, although small, are opposite each other in 2-4 pairs on the stem; and the seeds will have fluffy parachutes (pappus)—all typical of Arnica. This plant is sticky hairy.
Three sunny composite shrubs: Three shrubs add yellow splashes and swaths of color along roadsides, sage flats, and disturbed, dry habitats. Their genus names have been debated for years as the scientists sort out who is related to whom. Each species has several varieties, further indicating a range of often confusing characteristics.
Rubber Rabbitbrush – Ericameria/Chrysothamnus nauseosa – This 3-4-foot shrub adds panache to the grey-green hues of sagebrush habitats. The broad, rounded crown is colored by many narrow flower-heads clustered together on the ends of upright woody branches. The very narrow long leaves (1/8” wide to 4+” long) stick out from a grayish, furry stems (tomentose). The twigs have a milky latex sap which gives it its name.
Douglas Rabbitbrush – Chrysothamnus visidiflorus – Similar at first glance to Rubber Rabbitbrush and sometimes placed in the same genus, this shrub differs in being generally shorter 1-2’ shrubs; green, not gray, hairy young stems; and 2-3” oblong, usually twisted leaves which are a bit sticky (viscid).
Hairy Golden Aster – Heterotheca/Haplopappus/Chrysopsis villosa – The lowest growing of the three late-summer blooming shrubs, this somewhat woody species grows 6-12 ” in dry disturbed sites and road edges, often with blue Pacific aster. The leaves are hairy and slightly wavy, only about ½-1” long. The ½” flowers are a soft yellow. This genus remains a muddle taxonomically.
Blue to White Aster-like flowers: Taxonomically Aster is no longer Aster as scientists around the world have shared and refined their knowledge of this confusing group of plants. The Europeans claim the old Aster name. Our genus “Aster” is split now into several new groups with hard to spell and pronounce names. Below are the common names (still aster) listed with the new botanical names. Differences are based on growing habit, flower-head bracts, obscure pappus hairs, and invisible DNA. Luckily, some kinds are quite easy to tell apart once you look. Pollinators of aster flowers are typically bees and butterflies.
Thickstem Aster – Eurybia integrifolia – Common in meadows, these 1.5-2’ plants have thick, often purplish-red stems coated with sticky hairs. Stems branch mostly near the top, holding out deep-violet flower clusters. Each flower-head has loose, leaf-like bracts that are also very sticky. The glandular hairs form a gluey forest that deters small insects from creeping up the stems to lay their eggs in the larder of fattening seeds. The oval leaves clasp the upper stem, the lower leaves can be petioled.
Chaffy Asters – Eucephalus sp. The three Wyoming species of Chaffy Aster typically sport a few upright stems which are trimmed bottom to top with many alternating, oval to elongate leaves. The plants branch like candle-arbors near the top where a few sparse flowers are arrayed. Flower-heads have relatively few (6-12) showy ray flowers. The receptacle is elongate, covered with 3 rows of broad, dry (chaffy), triangular bracts arranged like shingles on a roof. These three species are often found growing among one another.
Nuttall Aster –Eucephalus elegans (Aster pereglans) –This species is the shortest and most elegant of the three, averaging 1-1.5’ or so. The flower-heads display 5-7 violet-purple ray flowers. The tightly arranged bracts are hairy, especially around the edges, and are often traced with purple. The oblong 2” leaves are neatly arranged up the stem.
Engelmann’s Aster – Eucephalus engelmannii –This aster stands up to 3-5’ tall and tends to lean out from the shade of forest edges or above other robust meadow plants. The large bright white, slightly ragged flower-heads cluster near the tips of the sparse branches. The straight stems are covered with many 3-4” oblong leaves.
Blue-leaf Aster – Eucephalus glaucus – Look for colonies of 1-2’ stems covered with gray-blue leaves. The flowers are white to pale lavender and the bracts are pale, smooth, and thin-textured. The overall appearance is rather ghostly. It lurks in relatively dry and high, often sunny, locations.
American Asters – Symphyotricum spp. – There are several truly aster-like asters that now have an impossible botanical name: Symphyotrichum (Sim-fee-o-trick-em). In case you really want to know, here are three (out of about 7) common showy species:
Pacific Aster – Symphyotrichum ascendens –One of the most common and tolerant asters, Pacific aster started blooming a few weeks ago and continues to do so along roadsides: from 6” where it may have been mowed or grazed, to 2+ feet where there is extra moisture. The light blue flower-heads grow along much of the stem. The bracts on the underside are shorter at the base and longer on the inside (ascending). The leaves are elongate and if you look closely, the venation is elongate too—these characteristics help us know it for sure.
Bracted Aster – Symphyotrichum eatonii – Found on stream edges with wet feet, this 2-4’ aster can at first be confused with Leafy Aster (below) as the blue flower heads have leafy bracts. However, the leaves of Bracted Aster are narrow and long ( >7x longer than wide), and the habitat is definitely wet. Flowers cover much of the plant and the stem is usually slightly hairy all over.
Leafy Aster – Symphyotrichum foliaceum – Just coming into bloom in moist meadows, near streams, and high elevations, this aster has broad oval leaves that often clasp the stem and several blue flower-heads with many ray flowers, which together create quite a show. Looking under the flower-head you can see the leaf-like bracts that give it its name. There are several varieties with different details of leaves, bracts, etc., but just “Leafy Aster” is fine.
Sagebrush – Artemisia spp. – Many people don’t realize that our common sagebrushes are wind pollinated members of the Aster family: they don’t have showy flowers but rather produce pollen in tiny composite heads with no ray flowers and only a few disc flowers.
Low Sagebrush – Artemisia arbuscula – A 1’ shrub that dominates Lupine Meadows in the park is now in bloom: 6-8” narrow stalks with tiny flower heads, each with about a dozen disc flowers, wave like wands and shed pollen to the wind—magic that any pollen meets a stigma surface to initiate seed formation. Its 1/4-1/2″ leaves have 3 lobes–like Big Sagebrush – held close to tough woody stems.
Soon our Mountain Big Sagebrush – Artimesia tridentata var. vaseyana — will wave about pollen too.
And other special plants:
Naked Broomrape – Orobanche uniflora – Rare to find, this peculiar plant has no chlorophyll but rather depends on its roots to connect it to other living plants for food. Saxifrages, sunflowers, and goldenrods are often its “host” plants.
Mountain Bog Gentian –Gentiana calycosa. – These deep blue, 6-8” plants with egg-shaped, opposite leaves unfurl their pleated petals to attract late flying pollinators such as bumble bees. Look for it blooming at high elevations .
Quiz plant*: This is the flower of a tall plant that is considered the harbinger of autumn. It colonizes abundantly after ____, a behavior that gives it its name. Answer below.
Enjoy hiking higher to see more showy blooms or looking closely with a hand lens at many wind pollinated plants. And don’t forget to look for fruits: berries, pods, capsules, etc. Fall is coming!
Frances Clark, Wilson, WY
*Quiz answer: Fireweed – Chamerion/Epilobium angustifolium – The 8 anthers open sequentially releasing pollen. Pollen grains are linked by microscopic hairs which become entangled in the hairs of its bee pollinators. These same micro-strings attach readily to the 4-parted stigma which has little bumps. In each flower, the anthers develop first, then the 4-lobed stigma expands, to avoid self-pollination. The plants bloom from bottom to top.