Hypericum kalmianum
(Kalm's St. Johnswort)

Other pictures of this plant:

               Seedpod                                           Leaf                                            Stem                                        Seed                                          Habit

Facts About this Plant:

    Common Names: Kalm's St. Johnswort
    Lifespan: Perennial
    Zones: 3 - 6
    Type: Forb
    Bloom Time: July - August
    Status: Native

Hypericum kalmianum, or Kalm's St. Johnswort, is native only to the Great Lakes states, excluding Pennsylvania. It is a perennial, which grows in several areas, like dry woods, but also moist sandy areas, like shorelines and fens. It blooms in mid summer with large yellow flowers.

There are a large number of Hypericum species in the United States, this species really only has one major lookalike, at least in its same native range, and that is Hypericum prolificum. There are several difference between them: Hypericum kalmianum is a smaller plant, usually reaching two to three feet at maximum, and the best way to tell them apart is the seed pods, where Hypericum kalmianum has a five-chambered seed pod with five styles at the top. Meanwhile, Hypericum prolificum can reach over six feet and it has a seed pod with three chambers (though it sometimes looks like a single chamber), and three styles on top. See photo below for comparison.

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