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A Comprehensive Guide to Flat-top Goldenrod (Euthamia graminifolia)

Flat-top Goldenrod (Euthamia graminifolia) is a herbaceous perennial that is found in the midwest and eastern United States and most of Canada except the far northern reaches. This plant, along with other goldenrods, is an important nectar source for many insects in the fall including the Monarch butterfly. It can grow up to 5 feet tall and has narrowly-lanceolate to linear leaves with entire margins. The golden yellow flowers bloom from July to October and it is hardy in zones 3-9. Along with Canada Goldenrod and wrinkle-leaf goldenrod , it is very common on roadsides and in fields.

Taxonomy and Naming of Flat-top Goldenrod (Euthamia graminifolia)

Herbarium specimen of flat-top goldenrod (Euthamia graminifolia).
Herbarium Specimen — Euthamia graminifolia (L.) Nutt. collected in United States of America by The New York Botanical Garden (licensed under CC BY 4.0)

Taxonomy

Flat-top Goldenrod (Euthamia graminifolia) was first named Chrysocoma graminifolia, by Carl von Linnaeus in Species Plantarum (1753) from a specimen collected in Canada (Sieren 1981). Later in 1840, Thomas Nuttall, an American botanist, renamed it to its current name of Euthamia graminifolia. Over the years it has also been placed in the Solidago genus with other goldenrods because of its similarity. This plant is a member of the Aster Family (Asteraceae).

Subspecies and Varieties

Flat-top goldenrod is the most variable species in the Euthamia genus (Sieren 1981) and has been placed in numerous varieties over the years. However because of overlap of the variability, all of the proposed varieties have been placed in the one species concept.

Meaning of the Scientific and Common Names

Scientific Name

The genus name, Euthamia, derives from the Greek words, Eu and thamees, which together mean to well (eu) crowded (thamees). The name comes from the dense flower clusters (Sieren 1970). The species name, graminifolia, derives from the Latin for grass-like, in reference to the leaves.

Common Names and Alternative Names

The common name is in reference to the flat topped flower clusters. Some other common names used, flat-top goldentop, flat-topped bushy goldenrod, creeping yellow weed, bushy goldenrod also refer to the flower shape and color. Other common names are descriptive of the leaves and include grass-leaf goldenrod, grass-leaved goldenrod, and lance-leaved goldenrod. Another, fragrant goldenrod, refers to the fragrance.

Physical Description

Close-up of yellow flowers of flat-top goldenrod (Euthamia graminifolia).
“Flat-topped Goldenrod (Euthamia graminifolia)” by wackybadger is licensed under CC BY-SA 2.0.
  • Plant Type: Herbaceous perennial
  • Height: about 2 to 5 feet tall
  • Leaves: sessile, alternate, simple, simple, narrowly-lanceolate to linear leaves that grow up to 4 inches in length and 0.5 inches in width. The leaves may have three to five veins showing.
  • Stem: Smooth or short-pubescent and can be become more pubescent and angled towards the top
  • Flower color: golden/yellow
  • Blooming period: July to October
  • Fruiting type and period: achene — August to November

Range of Flat-top Goldenrod (Euthamia graminifolia) in the United States and Canada

Range map of flat-top goldenrod (Euthamia graminifolia) in the United States and Canada.
Kartesz, J.T., The Biota of North America Program (BONAP). 2015. North American Plant Atlas. (https://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2015. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)].

This species is native to the northern tier and eastern United States and most of Canada except for the far northern reaches. It is considered rare in the states of Oklahoma, Kansas, Colorado, Wyoming, Idaho, and Washington and the Northwest Territories of Canada.

Habitat

Roadside in Europe with wildflowers.
Roadside verge full of wildflowers by Christine Johnstone, CC BY-SA 2.0, via Wikimedia Commons

This goldenrod grows in open areas such as fields, roadsides, shores, meadows, marshes and gardens. It is often found in wetland areas, but not always.

Hosted Species

Dichomeris Moth on white fabric.
Dichomeris moth — Donald Hobern from Copenhagen, Denmark, CC BY 2.0, via Wikimedia Commons

This species hosts a leaf-folding caterpillar (Dichomeris leuconotella) (Loeffler 1994).

Other Supported Wildlife

Goldenrod soldier beetle on a leaf.
Golden Soldier Beetle — NCBioTeacher, CC0 1.0, via Wikimedia Commons

This goldenrod is a nectar plant for a lot of bees, wasps, butterflies and beetles. Some of these include goldenrod soldier beetle (Chauliognathus pensylvanicus) and black blister beetle (Epicauta pensylvanica). Birds such as goldfinch and sparrow feed on the seeds in the fall.

Frequently Asked Questions

Is this plant poisonous?

The ASPCA does not list this plant as poisonous.

How has this plant been used?

This goldenrod is sometimes used in gardens as an ornamental plant and within its range, it will often plant itself whether you do or not. Native Americans have used the plant for pain and a pulmonary aid (Native American Ethnobotany Database).

What other goldenrods are similar to this goldenrod?

Flat-top goldenrod (Euthamia graminifolia) is similar to the great plains goldenrod (Euthamia graminifolia), but differs in that the former has a single vein in the leaf (Minnesota Wildflowers). This species is also similar to Riddell’s goldenrod (Solidago riddellii), but its leaves sheath the base (minnesotaseasons.com).

Is this goldenrod invasive?

This plant, though a native species, spreads easily via rhizomes and can display some invasive characteristics rapidly occupying nearby spaces. This has been noticed in the McMullen House Bed & Breakfast gardens but it is easily controlled and the blaze of yellow in the fall is worth it. This species is considered to be invasive in Europe where it has been introduced (gardenia.net). It is not considered as invasive as either Canada goldenrod or wrinkle-leaf goldenrod. This species has been noted in several sources to put out allelopathic chemicals, which may help in its invasiveness.

Does goldenrod cause allergies or hay fever?

Goldenrods in general, which do not cause hayfever, are often confused for ragweed (Ambrosia sp.), which cause the common hayfever. These plants bloom at the same time, which may lead to the confusion.

Gardening with Flat-top Goldenrod (Euthamia graminifolia)

Flowers of flat-top goldenrod (Euthamia graminifolia) in McMullen House garden.
Flowers of Flat-top Goldenrod — Robert Coxe, Image

Hardiness

This species is hardy in zones 3-9 and is present in most places in the United States except the far west and southwest. If your garden is present in these zones you may well be able to grow this plant if you have the right growing conditions. However, the hosted species, if outside the native range, may or may not be present.

Optimal Conditions

This goldenrod prefers places that have full sun or partial shade. Soils should be mesic to moist, but well-drained. It grows well in gardens and gives a nice background to otherwise shorter plants.

References

  • Loeffler, Carol C. 1994. Natural History of Leaf-folding Caterpillars, Dichomeris spp. (Gelechiidae), on Goldenrods and Asters. Journal of The New York Entomological Society 102: 405-428.
  • Sieren, David J. 1981. The Taxonomy of the Genus Euthamia. Rhodora 83:551-579.
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Robert Coxe

Robert Coxe

Robert Coxe is a professional ecologist and botanist who has worked as the State Ecologist of Delaware and as an ecologist for the Western Pennsylvania Conservancy. He is also a former Past-President of the Pennsylvania Academy of Science. He currently is an innkeeper at McMullen House Bed & Breakfast LLC and a web designer and owner for Silphium Design LLC.

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