Berteroa incana (Hoary Alyssum)

Plant Info
Also known as: Hoary False Madwort
Genus:Berteroa
Family:Brassicaceae (Mustard)
Life cycle:perennial
Origin:Europe
Status:
  • Weedy
Habitat:part shade, sun; dry fields, along roads, disturbed soil
Bloom season:April - October
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

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Detailed Information

Flower: Flower shape: 4-petals Cluster type: round

[photo of flowers] Rounded cluster 1 to 2 inches across at the end of branching stems near the top of the plant. Individual flowers are ¼-inch across and have 4 white petals that are deeply notched to look like 8. There are 6 thick yellowish green stamens in the center. The branching stems elongate as the plant matures, with fruit forming below and flowers just opened at the tip of the stem.

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

[photo of leaves] Leaves are 1½ to 3 inches long, up to ½ inch wide, toothless, have a pointed or blunt tip and no stalk. They are covered in fine hairs that give them a grayish green color. Attachment is alternate. Young plants also have a basal rosette of leaves that typically wither away by flowering time. Stems are densely hairy, single or multiple from the base, usually branching.

Fruit: Fruit type: capsule/pod

[photo of fruit] Fruit is a round, flat pod ¼ inch long with the stub of a style at the top. They run along the length of the elongated branching stems.

Notes:

Hoary Alyssum was once on the secondary noxious weed list for Minnesota. It is a weedy plant often found in empty lots, on roadsides, degraded fields, railroad rights-of-way, and other sunny locations with dry disturbed soil.

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More photos

Photos by K. Chayka taken at Long Lake Regional Park, 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: Dusty - Morrison County
on: 2010-06-16 22:15:44

We have these EVERYWHERE! Just wanted to put it out there that these cause sore feet in horses if eaten as they are toxic to them. Our Vet told us this today, so you can be sure that I will pull them out before we expand our pasture.

Posted by: Robyn - Litchfield
on: 2011-06-13 23:07:02

I see them on the sides of the road here. They are beautiful!

Posted by: Judith Bechtum, DVM - Rice Co
on: 2013-06-29 19:57:17

Hoary alyssum does cause severe metabolic disease in horses ( some seem to be more immune than others). They can develop diarrhea as well as inflamed feet (founder/laminitis), and associated side effects; some have to be euthanized. Most horses will not eat it unless they are food deprived, or it is in their hay. The disease is somwhat dose dependant, as well as individually susceptible. It is a serious toxic weed for horses.

Posted by: Jane - IGH, Dakota County
on: 2015-06-13 13:04:36

This popped up in my backyard, which has very sandy soil. It is growing vigorously on the edge of my woodland. I waited for it to flower so I could identify it. I shall now remove the alien invader.

Posted by: Melissa - Bemidji
on: 2015-06-21 12:31:18

These are growing alongside the Paul Bunyan State Trail going south out of Bemidji.

Posted by: Andrea - Duluth, Park Point
on: 2016-08-02 14:58:12

This grows all over the sidewalks and in vacant lots.

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