Nuttallanthus canadensis (Old-field Toadflax)

Plant Info
Also known as: Blue Toadflax, Canada Toadflax
Family:Plantaginaceae (Plantain)
Life cycle:annual, biennial
  • State Special Concern
Habitat:sun; dry sandy soil, prairies, roadsides
Bloom season:May - July
Plant height:4 to 20 inches
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: irregular Cluster type: raceme

[photo of flowers] Flowers are in a spike-like raceme at the top of the stem that elongates up to 8 inches. Individual flowers average about 1/3 inch long, irregular with an upper lip divided into 2 erect rounded lobes, and a lower lip with 3 rounded lobes. Flower color is blue to blue-violet, with a 2-humped white spot at the base of the lower lip. There is usually 1 spike on a stem, but a plant may have multiple stems.

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

[photo of leaves] Leaves are 1 to 1½ inches long and very narrow—not more than 1/8 inch wide, toothless, hairless, with pointed tips and no leaf stalk. They are alternately attached and narrower on flowering stems, but oppositely attached and broader on the shorter non-flowering stems. The main stem is smooth and slender, green to reddish brown.

Fruit: Fruit type: capsule/pod

Fruit is a small, rounded capsule containing many tiny seeds.


Old-field Toadflax, formerly Linaria canadensis, is an uncommon species in Minnesota, where it reaches the northwest limit of its range. According to the DNR, it has only been documented about 25 times in the state, primarily in sparsely vegetated, sandy soils that have been recently disturbed, such as pocket gopher mounds or even plowed fields. I encountered it one year in a sandy horse trail at Wild River State Park but it disappeared in subsequent years. Commercial development, agriculture and invasive species have all contributed to either destruction or degradation of suitable habitat and it was listed as a Special Concern species in 2013. With its small flowers and foliage and slender stems, this may be easy to miss unless there is a clump of plants together. It superficially resembles Kalm's Lobelia (Lobelia kalmii), which has spoon-shaped basal leaves and is found it moister habitats.

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More photos

Photos by K. Chayka taken at Wild River State Park, Chisago County. Photos by Peter M. Dziuk taken in Sherburne National Wildlife Refuge.


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

Posted by: Rick - cass county
on: 2014-09-25 10:42:46

Found something extremly similar to these growing in dense shade next to some ferns by Longville, MN. But the ones I found are different colors, violet, white and yellow and have only one flower at the top of the stem.

Posted by: K. Chayka
on: 2014-09-26 18:15:35

Rick, the flower sounds like Viola tricolor, a.k.a Johnny jump-up.

Posted by: Jason - Marine on St. Croix
on: 2015-06-01 14:20:49

We found some Linaria canadensis today in Andover, Anoka County. First time I have ever seen this in the field or anywhere for that matter. Sandy, south facing exposed bank.

Posted by: Brett - Sherburne County
on: 2020-05-30 21:44:33

Were in bloom today in Sherburne county. Along easement and many others in sandy areas. Very small flowers so easy to miss.

Posted by: Jason - Sherburne County
on: 2020-06-04 22:35:53

Found these blooming May 28th at Uncas Dunes SNA along sandy horse trail. Understated beauty.

Posted by: Nancy Docherty - Oak Park Heights--Washington CO
on: 2020-07-19 14:40:41

In an area with Lobelia cardinals and Liatris pycnostachya. Probably planted by a wild flower landscaping co. after a new building went up.

Posted by: Leanne Hinke - Houston Co on Miss. River sandy beach
on: 2024-05-20 09:04:41

Across the river from the power plant at Genoa. On a sandy beach on May 19, 2024. Blooming. Noted at least a half dozen plants.

Posted by: Brett W - Sherburne county
on: 2024-06-08 21:01:04

The restoration disturbance seems to have helped these in the SNA here. Lots more blooming in the open sandy areas created recently.

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