Solanum rostratum (Buffalo Bur Nightshade)

Plant Info
Also known as: Kansas Thistle
Genus:Solanum
Family:Solanaceae (Potato)
Life cycle:annual
Origin:native
Status:
  • Weedy
Habitat:sun; dry, along roads, waste areas
Bloom season:June - September
Plant height:1 to 3 feet
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,

Notes:

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.

Comments

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.

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