Polygala sanguinea (Blood Milkwort)

Plant Info
Also known as: Purple Milkwort, Field Milkwort
Family:Polygalaceae (Milkwort)
Life cycle:annual
Habitat:sun; moist; fields, bogs, fens
Bloom season:July - September
Plant height:4 to 12 inches
Wetland Indicator Status:GP: FACW MW: FACU NCNE: FACU
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: indistinct Flower shape: irregular Cluster type: spike

[photo of flowers] Flowers arise in dense, cylindrical spike-like racemes at the top of the plant and the tips of branching stems. Flowers are flanked by a pair of spreading, oval to egg-shaped, petal-like sepals, each up to ¼ inch (4 to 6 mm) long, about half as wide, rounded to blunt at the tip and have a conspicuous midvein. Three small petals are fused into a short column in the center, fringed with stubby yellow lobes at the tip. Color ranges from pink to purple, rarely white, though commonly fades with age. Flower clusters are about ½ to ¾ inch (to 2 cm) in diameter and elongate during the growing season, with flowers blooming at the tip and fruit forming below.

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

[photo of leaves] Leaves are alternate, up to 1½ inches (1 to 4 cm) long, linear to narrowly elliptic, widest near the middle, blunt to pointed at the tip, toothless, hairless, and stalkless or nearly so. Stems are square or ribbed, hairless, usually branched in the upper plant.

Fruit: Fruit type: capsule/pod

[photo of lower spike where fruit forms] Fruit is a small round capsule containing 2 hairy seeds. The lateral sepals become erect as the capsule develops, overlapping like fish scales and the color often fading to pale pink or greenish white. Sepals and capsules both drop off at maturity leaving a tiny floral bract on the stem.


The flowers are vaguely similar to those of the related Cross-leaved Milkwort (Polygala cruciata), which is far less common though they may be growing side by side; it has leaves typically whorled in 4s, is shorter statured, and the sepals remain spreading like wings throughout the season.

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More photos

Photos by K. Chayka and Peter M. Dziuk taken in Anoka County.


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

Posted by: Ian - St. Paul
on: 2014-07-21 14:46:31

Saw this out in Belwin prairie near Afton. Unusual place for it given it's preferred habitat (Belwin is quite sandy), but there was evidence of standing water around.

Posted by: Brian - St. Peter
on: 2015-07-21 22:57:00

There's a great display of this species right now at many places on the main rock outcrop area far along the trail from the southern entrance to Louisville Swamp in Scott County.

Posted by: Ivan - Wing River Twp Wadena Co.
on: 2019-09-05 14:03:34

I have Photo if needed. Found doing survival check in tree planting. 9/4/19

Posted by: Barbara H Fleischman - Elgin
on: 2021-10-09 15:03:21

I saw this plant in the fen area in Chester Woods Park, east of Rochester. Blooming 10-6-21. Other plants around it included strawberry, violets, and bottle gentian.

Posted by: Rachel Rusten - Kittson County
on: 2022-06-29 10:11:59

I saw this in bloom 07-06-21 in Skull Lake WMA east of Hallock, MN. I posted on iNaturalist and found this was the most northernmost occurrence of this species to be recorded

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