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Hypericum perforatum L.

St. John’s wort, common St. John’s wort, common St. Johnswort

Common St. John’s wort is a native of North America, Europe, Asia Minor, Russia, India, and China.

Plants: Less than 3′ (91 cm) in height, and multiply branched.

Leaves: Oval, opposite, sessile, up to ⅝ ⨉ ¼″ (1.8 cm ⨉ 7 mm), with smooth edges.

Flowers: Deep yellow, star-shaped, with a central, brushlike spray of stamens. If you look closely, there is a rounded ovary about ⅛″ (3.2 mm) in diameter, from which emerge three styles, arranged like the legs of an inverted tripod. They are difficult to see because they are almost the same color and shape as the stamens, but they are longer and thicker. Some species of St. John’s wort have only a single style, so this is an identifying characteristic. Petals have serrated edges and small black dots on the serrations. Flowers are up to ⅞″ (2.5 cm) across.

Fruits: Capsules ¼–5/16″ (7–8 mm) long, with three valved seeds chambers. Seeds are about 1/32″ (1 mm) in size, black, rough, and lustrous. A single plant produces 15,000 to 34,000 seeds.

Habitats: Open woods, roadsides and waste places, hedge banks and grassland, and in dry sunny places, usually on calcareous soils.

Medical: St. John’s wort is widely used to treat depression, and a number of studies have been performed to assess the efficacy of these treatments. Studies have reported contradictory results, and this has become a contentious issue, in part because pharmaceutical companies stand to lose a very profitable business in other antidepressant drugs. Some studies have concluded that St. John’s wort is more effective than placebo and equally as effective as tricyclic antidepressants, and roughly as effective as serotonin reuptake inhibitors such as Prozac and Zoloft. Other studies suggest no benefits. It is likely that St. John’s wort at least helps with depression.

Some types of St. John’s wort.

Online References:

Wikipedia

Plants for a Future

Wikimedia Commons

 

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

8/20/2025 · Peaks Island, Maine · ≈ 11 × 8″ (27 × 20 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

7/2/2014 · Conservation Area, Shirley St., Groton, Mass­a­chu­setts · ≈ 4½ × 7″ (11 × 16 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

7/5/2021 · Curtis Farm Preserve, Harpswell, Maine · ≈ 4 × 2½″ (10 × 6.7 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

6/24/2015 · Nashua River Rail Trail, Groton Ctr, Groton, Mass­a­chu­setts · ≈ 3½ × 2½″ (9.4 × 6.9 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

6/24/2015 · Nashua River Rail Trail, Groton Ctr, Groton, Mass­a­chu­setts · ≈ 4 × 3½″ (11 × 9.7 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

7/9/2010 · Nashua River Rail Trail, Groton Center, Groton, Mass­a­chu­setts · ≈ 3½ × 2″ (8.7 × 5.4 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

6/16/2010 · Nashua River Rail Trail, Groton Center, Groton, Mass­a­chu­setts · ≈ 9 × 6″ (23 × 15 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

7/20/2021 · Otter Brrok Preserve, Harpswell Heritage Land Trust, Harpswell, Maine · ≈ 3½ × 2″ (8.7 × 5.8 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

6/29/2014 · Mount Agamenticus, York, Maine · ≈ 8 × 6″ (20 × 14 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

7/2/2015 · Bemis Rd., Pepperell, Mass­a­chu­setts · ≈ 4 × 6″ (10 × 16 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

6/28/2017 · Andres Art Institute, Big Bear Mountain, Brookline, New Hamp­shire · ≈ 4 × 3½″ (10 × 9.3 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

7/3/2005 · Pepperell, Mass­a­chu­setts

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

7/17/2019 · Oceanview, Falmouth, Maine · ≈ 3 × 2½″ (8.1 × 6.3 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

7/2/2015 · Bemis Rd., Pepperell, Mass­a­chu­setts · ≈ 1½ × 1½′ (57 × 50 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

7/27/2009 · Nashua River Rail Trail, Groton, Mass­a­chu­setts · ≈ 5 × 3½″ (12 × 9.5 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

7/9/2010 · Nashua River Rail Trail, Groton Center, Groton, Mass­a­chu­setts · ≈ 3 × 2″ (8.2 × 5.8 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

7/17/2019 · Oceanview, Falmouth, Maine · ≈ 2½ × 3½″ (6.3 × 8.8 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

6/24/2015 · Nashua River Rail Trail, Groton Ctr, Groton, Mass­a­chu­setts · ≈ 8 × 6″ (20 × 14 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

7/28/2013 · Andres Institute of Art, Big Bear Mountain, Brookline, New Hamp­shire · ≈ 10 × 7″ (25 × 16 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

6/24/2025 · Hackett and Minot Trails, Harpswell, Maine · ≈ 9 × 7″ (22 × 18 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

6/24/2015 · Nashua River Rail Trail, Groton Ctr, Groton, Mass­a­chu­setts · ≈ 9 × 6″ (23 × 15 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

7/17/2019 · Oceanview, Falmouth, Maine · ≈ 4 × 3″ (10 × 8.4 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

Notice the little black dots along the edges of the petals. · 7/21/2013 · Gibbet Hill, Groton, Mass­a­chu­setts · ≈ 1¾ × 2½″ (4.7 × 6.4 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

6/21/2010 · Nashua River Rail Trail, Groton Center, Groton, Mass­a­chu­setts · ≈ 3 × 2½″ (7.9 × 6.6 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

7/13/2015 · Mt. Ascutney State Park, Ascutney, Ver­mont · ≈ 4 × 4″ (10 × 10 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

7/11/2026 · Spear Farm Estuary Preserve, Yarmouth, Maine · ≈ 6 × 4″ (14 × 10 cm)

Hypericum perforatum (St. John’s wort, common St. John’s wort, common St. Johnswort)

6/16/2010 · Nashua River Rail Trail, Groton Center, Groton, Mass­a­chu­setts · ≈ 4½ × 7″ (11 × 17 cm)

KingdomPlantaePlants, but not fungi, lichens, or algae (from Stearn's Botanical Latin)
SubkingdomTracheobiontaVascular plants—plants with a “circulatory system” for delivering water and nutrients
DivisionMagnoliophytaFlowering plants, also known as angiosperms
ClassMagnoliopsidaDicotyledons—plants with two initial seed leaves
SubclassRosidaeRoses, legumes, proteas, dogwoods, hydrangeas, mistletoes, euphorbias, grapes, many more
OrderMalpighialesA broad group encompassing 16,000 species
FamilyHypericaceaeSt. John’s Wort family
GenusHypericumFrom ancient Greek hyper, “above,” and eikon, “picture,” from an old practice of putting flowers above a picture to ward off evil spirits
Speciesperforatum“Perforated,” for paired leaves joined at the base and “perforated” by the stem

About plant names...

Range:

About this map...

Hypericum perforatum description by Thomas H. Kent, not updated.

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