Solanum rostratum (Buffalo Bur Nightshade)

Plant Info
Also known as: Kansas Thistle
Family:Solanaceae (Potato)
Life cycle:annual
  • Weedy
Habitat:sun; dry, along roads, waste areas
Bloom season:June - September
Plant height:1 to 3 feet
Wetland Indicator Status:none
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

Pick an image for a larger view. See the glossary for icon descriptions.

Detailed Information

Flower: Flower shape: 5-petals Cluster type: raceme

[photo of flowers] Flowers are in a raceme that elongates up to 6 inches, blooming from the bottom up. Individual flowers are about 1 inch across with 5 bright yellow fused petals with crinkled or wavy edges. There are 5 tubular stamens and a long curved style in the center. The calyx is hairy and/or spiny with linear lobes. One plant has a few to several racemes on its many branches.

Leaves and stem: Leaf attachment: alternate Leaf type: lobed Leaf type: simple

[photo of leaves] Leaves are up to 6 inches long and 5 inches wide, with irregular and deep rounded lobes. There are long, sharply pointed, yellow prickles along the major veins on both sides of the leaf, and on the leaf stalk. Edges are toothless, surfaces are hairy.

[photo of stem] Stems are heavily branched and covered in sharp yellow prickles that are typically purplish at the base.

Fruit: Fruit type: barbed Fruit type: berry/drupe

[photo of fruit] Fruit is a many-seeded berry encased in a spiny covering,


This is one mean plant—every part of it is covered in very sharp, spiny prickles. It's interesting to look at, but touch at your own risk! There are different opinions of where this plant originates, but the consensus seems to be it is native to the U.S., but not necessarily the Upper Midwest. Still, the MN DNR lists it as native, so we do, too. It was once 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 at a construction site in Ramsey County. Other photos courtesy Peter M. Dziuk.


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

Posted by: M. R. - Eden Prairie
on: 2009-07-16 19:25:38

I removed a great deal of rock that had been under the deck for years. Before I've figured out my plan for the space and what would grow best, two of these have appeared on their own and are quite pretty. Mine have only grown to about 6" tall thus far, but they have the yellow flowers and the thorns all over. I had never seen them before, so found this site in trying to identify what they were.

Posted by: clyde - menahga
on: 2009-07-25 11:36:44

I found a single Buffalo Bur Nightshade plant growing under my birdfeeder. Thanks to your website I was able to identify it.

Posted by: Casey - Saint Paul
on: 2011-06-28 15:31:15

I have rock surrounding my home and one of these has managed to grow next to my front steps sprouting out from the rock. It's about 16 inches. I was trying to identify it and found this website. Thanks

Posted by: Steph - Royalton MN
on: 2012-08-08 10:40:04

We had one of these growing just off the edge of our patio. I kept it around for a while to see what it would grow into. Then googled it and seen it's not a great plant to have around. I think it came home with my hubby from working in ND.

Posted by: Chris - Mankato
on: 2013-08-18 20:24:26

This plant appeared and flowered after we trimmed out dead cranberries. I'm glad there's only one! I really appreciate having a website like yours for help with identifying wildflowers.

Posted by: David - Winona Co.
on: 2014-08-04 15:23:52

I found it growing in disturbed soil under the bird feeder at the Whitewater WMA. Waited for the bloom now I will kill it.

Posted by: vickie - Apple Valley
on: 2016-07-15 16:37:55

looked in several luck. thanks for having this on your website. One has been growing under my bird feeder and next to a Potentilla bush. I think it is pretty but don't like the prickles. Will keep it for a while longer. Love your site. Thanks again.

Posted by: Tina - St Paul
on: 2017-07-09 13:47:25

We have lived here 25 years and it just appeared. Not sure if we should keep it or not.

Posted by: Janet N - Bemidji
on: 2017-07-21 20:06:51

Showed up in the rocks surrounding our water feature. I've never seen it before now. Pretty and interesting to look at but I guess I'll have to find some Kevlar gloves to pull this bad boy before it spreads seed!

Posted by: Becky - Not MN Southern calif
on: 2018-05-10 23:54:17

This plant just appeared in my garden. Was glad to find out what it was have no idea where it came from

Posted by: Sue S. - Northome
on: 2018-07-13 11:07:26

Gardener, Ann L., in Northome, MN, reported to our UM Extension Office of unusual plant she had never seen before in her flower bed (in town). Looked like maybe a volunteer tomato when it first sprouted. Then she spotted all the prickles and nasty-looking spikes on the leaves once the yellow flowers appeared. She pulled it so it wouldn't spread.

Posted by: Rick a - Crow wing county
on: 2018-07-15 20:31:51

I discovered one of these plants growing under my bird feeder. I noticed several other people found them under bird feeders as well. So I am wondering if possibly bird seed may have these mixed in occasionally. I live near Crosby Minnesota.

Posted by: SSG - Maple Grove
on: 2018-08-02 13:41:53

I pulled out a deck that had been there for 20+ years and a half dozen have appeared there as a surprise. They look nasty even when small. Thanks for helping me confirm that I do not want to keep them.

Posted by: HS - Minneapolis - Airport Dog Park
on: 2018-08-20 20:14:00

Found some of the burrs stuck to my dog at the airport dog park, which consequently got stuck in myself. Nasty little things when they poke into you. Definitely sting and burn.

Posted by: Kirsten Zoellner - FOUNTAIN
on: 2019-02-09 14:44:38

We have these in our agricultural dry lot in Fillmore County. We've been pulling (ouch!) them and burning them in a concrete water tank that is no longer used.

Posted by: Jim Folden - Kasota
on: 2019-07-09 22:05:07

Found 1 in my garden. I did not recognize it so I let it grow, until it was big enough to identify. Mean looking plant, I hope not to see again!

Posted by: Mark Wheeler - Oakdale
on: 2020-06-25 18:27:51

Found in my garden June 2020. A first for me. When it first came up, I thought it might have been a watermelon because of the leaf shape. Nope!

Posted by: Courtney Kerns - Cohasset
on: 2020-06-30 16:50:49

One of these very distinctive plants is growing underneath a bird feeding area at the new house I moved into three weeks ago. Add me to the “it must’ve come in on birdseed” group! Previous owners had the feeder suspended from the cable where my feeder now hangs.

Posted by: Julie Miedtke - Harris Township, Itasca County
on: 2020-07-13 09:43:32

This plant popped up in a flower bed----it has since been removed. Nasty thing!

Posted by: George Nasman - Watonwan County
on: 2020-07-14 22:27:49

I just discovered this weed in my muskmelon patch which was an old cow pasture that hadn't been plowed up for 20 years until this spring. I must have pulled 50 - 75 today & will finish tomorrow, The thorns will penetrate right through my leather gloves if I'm not careful while pulling them. They're nasty & I want to exterminate them for good.

Posted by: Angela Marshall - Ogilvie
on: 2020-07-25 00:15:56

Have 2 of these in my garden. We put in dirt from a 20 year old manure pile to help buildup the garden. Kanabec county. I haven't removed them yet because I wasn't sure what they were.

Posted by: Andrew - Worthington
on: 2020-08-08 16:05:29

Had a small section of pasture that the sheep overgrazed (it's a paddock junction); had a few of these pop up last month and the sheep completely left them alone. Appreciate the info as I wasn't sure how concerned I needed to be about them.

Posted by: Gregory - savage
on: 2020-09-03 12:30:13

I am yet another to have discovered this under a bird feeder, in mostly clay type soil.

Posted by: Mac - Terrace
on: 2022-05-17 17:48:41

Found one of these growing on our property outside of Glenwood last year. Personally, I think it is quite a beautiful plant and it is native, after all. A weedy native however, and one I certainly pulled and disposed of after it flowered. I like bizarre and weird plants, though. I am actually fascinated by the Solanaceae species and have been experimenting with a few of them, both native and exotic, via seed I have collected in my travels or bought from a seed source. Hybrids anyone? Just kidding! Some Solanum's can be very weedy and others not so much. It is definitely a very interesting family of plants that includes Tomato's, Potato's, Peruvian Golden Berries, Goji Berries, Tree Tomato's and a host of others that Human's use for food. Many have other uses as well. A very useful group of plants. This is such a great site, btw. It is also very useful! Thank you so much for the info and Happy Growing to all.

Posted by: gary - Cartlton County
on: 2023-06-02 21:42:36

A single plant appeared in the debris under one of my bird feeders a few years ago. It may have been from a seed in a bag of black oil sunflower seeds.

Posted by: Diane Miller - Southeast Anoka County in Blaine
on: 2023-06-10 15:35:34

It sprouted up next to my brick planter by my front steps. At first it looked like watermelon leaves but then noticed the yellow flowers and prickley stems. This was the only site that it could be identified. Thank You. Birds often perch on the planter, so assume seed was spread by them.

Posted by: Chris Larson - Redwood County
on: 2023-06-23 01:36:42

Two of these well-armed plants showed up on a pile of gravel I'd scraped up off my driveway. I thought they looked like tomato relatives, only meaner. Yikes.

Posted by: Molly Stoddard - Fergus falls
on: 2023-07-11 17:19:30

Appeared in my back yard in the shade. Have not seen it before. Love my native plants but may need to relocate this one out of my yard because those seeds look nasty for my dog to step on.

Posted by: Angie Piltaver - St Peter/Nicollet Co
on: 2023-07-12 14:24:55

Found one of these today under an area where we too put out bird seed in a tray. Looks like this is a common theme. I've seen this plant listed as "native" and as a "noxious weed"... Given that we have a dog and wildlife that comes around our yard, looks like we will be removing it ... After we get some Kevlar gloves. 😏

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