Anthoxanthum hirtum (Sweetgrass)

Plant Info
Also known as: Northern Sweet Grass, Vanilla Grass
Genus:Anthoxanthum
Family:Poaceae (Grass)
Life cycle:perennial
Origin:native
Habitat:part shade, sun; moist to wet; marshes, sedge meadows, wet prairies, forest edges, wet ditches
Fruiting season:June - July
Plant height:16 to 36 inches
Wetland Indicator Status:GP: FACW MW: FACW NCNE: FACW
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: indistinct Cluster type: panicle

[photo of flowering panicle] Open panicle at the tip of the stem, taller than wide, 2 to 6 inches long, pyramidal in outline, the main branches mostly paired at the stem nodes and widely spreading, the lowest branches often slightly drooping. Spikelets (flower clusters) are single at branchlet tips, about ¼ inch (to 6.3mm) long, green usually tinged with purple, somewhat flattened, elliptic to egg-shaped with a pointed tip, each with a single fertile floret flanked by a pair of staminate (male) florets and mostly hidden by them. Branch and spikelet stalks are slender and wiry, green to purple.

[photo of flowering branch and spikelet] At the base of a spikelet is a pair of bracts (glumes) that are thin, translucent around the edge, broadly egg-shaped with a pointed tip, keeled, 1 to 3-veined, 4 to 6.3 mm long, the upper and lower glumes about equal and as long as the spikelet. Surrounding a floret is a pair of bracts (lemma and palea), the lemma hairy especially near the tip and around the edges, the edges wrapping around the floret and mostly hiding the palea. Staminate lemmas are 3 to 5 mm long, elliptic with a point or short awn at the tip, keeled and obscurely 5-veined. Fertile lemmas are egg-shaped, pointed at the tip, 2.9 to 3.5 mm long, without a keel, shiny and usually shorter than the staminate lemma.

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

[photo of sheath, ligule and upper leaf] Leaves are alternate, flat, hairless and shiny on the lower surface, hairless to finely hairy on the upper surface. Lower and vegetative leaves are 7 to 12 inches long, less than ¼ inch (2 to 5mm) wide, the 2 or 3 stem leaves only 3/8 to 2 inches long and slightly narrower. Stem sheaths are mostly smooth, the edges overlapping near the tip. The ligule (membrane where the leaf joins the sheath) is 2.5 to 5.5 mm long and ragged along the top edge. Basal sheaths may be bladeless. Stems are smooth, single or a few from the base forming loose clumps, unbranched, and typically form colonies from long, creeping rhizomes.

Fruit: Fruit type: seed without plume

[photo of spikelet] Fertile florets turn light brown and drop away when mature, leaving the glumes and staminate florets behind persisting on the stalk.

Notes:

Sweetgrass, formerly known as Hierochloe odorata, is a cool season grass of moist places. The common names come from the vanilla-like fragrance of its leaves, which retain their scent when dried. A showy spring-bloomer, the largish, purplish spikelets on wiry stalks, hairy florets only one of which is fertile, long ligule, typically short stem leaves, and rhizomatous growth are a unique combination.

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More photos

Photos courtesy Peter M. Dziuk taken in Cook, Houston, Lake and Polk counties.

Comments

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

Posted by: jenifer w - lake bimidji
on: 2017-10-02 22:08:51

its all along the bike path around the lake

Posted by: Cathy Lindsey - Lutsen
on: 2020-07-08 08:29:35

I have seen a few sweetgrass plants on Cook County Rd 34, a gravel road between Highway 61 and Lake Superior. They grow on the very edge of the road, which the County will mow. I am wondering about digging up just a few plants and transplanting them to a safe place on our property.

Posted by: K. Chayka
on: 2020-07-08 09:46:03

Cathy, this is a common species, not at risk of extinction, and may be accustomed to the occasional mowing. I wouldn't worry about it.

Posted by: Crystal - Minneapolis
on: 2020-08-02 22:55:32

Does anyone know where to find sweet grass in Minneapolis or the metro area? I can't find any, anywhere :(

Posted by: K. Chayka
on: 2020-08-03 07:05:16

Crystal, see "where to buy native seeds and plants" that shows on most pages of this website, or check the map of native plant purveyors. If those nurseries don't carry it one may know who does. In any case, pickings are slimmer this time of year so you may have to wait for a restock.

Posted by: Kelvin - Mille lacs lake
on: 2020-09-10 21:20:49

Hi, I've been looking for someone to show me where I can find an gather sweet grass in the wild, when it would be an appropriate time to gather, how to dry and braid the plant for ceremonies or basket weaving. Or maybe if someone could point me in the direction of where the plant grows Close to Mille Lacs Lake, in Central Minnesota

Posted by: K. Chayka
on: 2020-09-10 21:50:02

Kelvin, for specific locations, you can try using the Bell Herbarium online atlas to see where it's been recorded in the past, but you should not collect plants from the wild without the landowner's permission. You could grow your own instead of taking plants from the wild; check the native plant nurseries and see if they sell sweetgrass seeds or plants.

Posted by: Carol Charging Thunder - St Paul
on: 2020-09-14 11:52:39

Hi my name is Carol Charging Thunder and altho we use Sweet Grass in our ceremonnies I would like to know more of this beautiful plant that we use as an incense with prayers. we call this plant - wachanga which we also braid -wachanga sunpi. this plant grows in the wild thank you

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