Grindelia squarrosa (Gumweed)

Plant Info
Also known as: Curlycup Gumweed, Curly-top Gumweed
Genus:Grindelia
Family:Asteraceae (Aster)
Life cycle:biennial, short-lived perennial
Origin:native
Habitat:sun; disturbed soil; fields, prairies, along roads and railroads
Bloom season:July - October
Plant height:6 to 36 inches
Wetland Indicator Status:GP: UPL MW: FACU NCNE: FACU
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

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Detailed Information

Flower: Flower shape: 7+petals

[photo of flowers and bracts] 3 to 20 flower heads per plant, each 1-inch across with 25 to 40 yellow petals (ray flowers) around a yellow center disk, the disk about as broad as the rays are long. The narrow bracts surrounding the base of the flower are in 5 or 6 layers; bracts are spreading, strongly curved, and exude a sticky resin.

Leaves and stems: Leaf attachment: alternate Leaf type: simple

[photo of leaves] Leaves are 1 to 2½ inches long, somewhat variable in shape but generally oblong with a pointed tip, stalkless, more or less clasping, and typically twisted in relation to the sun's position. Edges are toothed, the teeth pointed or more often rounded. Surfaces are hairless and gland-dotted. Uppermost leaves are smaller, more linear and may be toothless or nearly so. Stems are erect to ascending, often heavily branched in the upper plant, hairless, straw-colored to tinged red.

Fruit: Fruit type: seed without plume

Fruit is a dry, brown seed without hairs but with 2 to 8 awns at the tip.

Notes:

Gumweed is easily identified by its unusual bracts. It is typically found along roadsides, railroads, and other disturbed soils. At one time it was considered a county-level noxious weed but Round-up Ready crops took care of that.

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More photos

Photos by K. Chayka taken in Lake and Ramsey counties. Other photos courtesy Peter M. Dziuk.

Comments

Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Dean W - Blue Mound State Park
on: 2009-08-27 18:36:30

We visited Blue Mounds, Split Rock, Camden, and Shetek state park this last weekend. We observed gumweed at Blue Mounds (rock county) and Camden (Lyon county). Our book lists it as gumweed but I notice some books call it curly cup gumweed. There is also a pasture two miles from where I live in Brown county that is loaded with gumweed. Is this gumweed and curly cup gumweed one and the same.

Posted by: K. Chayka
on: 2009-08-27 21:21:19

Most plants go by multiple names--some have a dozen or more common names, and may have multiple scientific names as well, all referring to the same plant. It can be very confusing.

Chances are the 2 are the same plant.

Posted by: Sonja - McGrath
on: 2010-12-12 12:37:06

Why is this plant listed as a Noxious weed? It looks gorgeous.

Posted by: K. Chayka
on: 2010-12-12 17:37:20

In MN, "noxious" often means an agricultural pest more than an ecological pest. That was true in this case and some MN counties had declared it a problem weed for that reason.

Seems it's been removed from the latest lists, just recently released by the DNR and the MN Noxious Weed Advisory Committee. I'll drop that designation.

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