Lobelia dortmanna (Water Lobelia)

Plant Info
Also known as:
Family:Lobeliaceae (Lobelia)
Life cycle:perennial
Habitat:sun; lake edges, shallow water
Bloom season:July - September
Plant height:10 to 40 inches
Wetland Indicator Status:GP: none MW: OBL NCNE: OBL
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 Flower shape: tubular Cluster type: raceme

[photo of flowers] Loose raceme on the emergent portion of a hollow stem, rising up to 12 inches above the water surface. Flowers are pale blue to white, ½ to ¾ inch long, the petals forming a long tube with 3 lower lobes of similar size and 2 smaller upper lobes. The lower lobes are hairy at the base. 5 short lance-like sepals surround the base of the tube, set upon a short stalk.

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

[photo of leaves] Leaves are usually submerged, linear and flattened with a blunt tip, hollow, 1 to 2 inches long, forming a basal rosette of arching blades. Stem is hollow and unbranched.

Fruit: Fruit type: capsule/pod

[photo of fruit] The fruit is a nodding, conical barrel-like capsule about ½ inch long with the remnant of the style attached at the tip.


A decidedly northern species, Lobelia dortmanna is relatively common in the cool, clear tanin-stained lakes of the Arrowhead region. While only the emergent 10-12 inches is visible, the hollow, underwater portion of the flower stalk can be up to 3 feet long! Flowers can even bloom and set seed under water. When not in bloom, the hollow, blunt-tipped leaves distinguish Water Lobelia from other aquatic species.

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More photos

Photos by K. Chayka taken at Toohey Lake, Cook County. Photos courtesy Peter M. Dziuk taken at Toohey Lake and at Divide Lake, Lake County.


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

Posted by: Sherrie Hood - Litner Point, Burntside Lake, Ely MN
on: 2020-07-12 17:42:38

Have a clear photo of it in a small group showing basal leaves. Photo is not detailed for flowers.

Posted by: Susan Premo - Fenske lake, st. Lois county
on: 2021-06-24 15:14:43

So fun to identify this water plant. Just near the waters edge, and had to find out its name, great site!!

Posted by: Regan Golden - Parent Lake, Boundary Waters Canoe Area
on: 2022-08-01 22:36:51

We found a 3 x 8 ft. patch of this plant growing in Parent Lake in the BWCA, it was in full bloom at the end of July. What an amazing plant! So beautiful.

Posted by: Bruce Ludewig - BWCAW
on: 2024-01-07 22:37:50

Kawishiwi River between Lake Poly and Koma Lake, on 7/17/20.

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