Common St. John's wort is a native of North America, Europe, Asia Minor, Russia, India, and China.
Identification: Plants are less than 3′ (91 cm) in height, and multiply
branched. Leaves are
oval, opposite, sessile, up to ⅝″ (1.8 cm) ×
¼″ (7 mm), with smooth edges.
Flowers are 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.
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.
Below is a comparison of some species of St. John's wort:
7/18/2017 · Tobyhanna State Park, Pennsylvania · ≈ 5 × 3″ (12 × 8.4 cm)
8-20″ (20-50 cm) tall. Stems are hairless, somewhat 4-angled.<
4-18″ (10-45 cm) tall, sometimes up to 2½′ (79 cm), heavily branched, with a shrublike habit. Branches may be 4-angled or smooth, tapering, and sometimes winged.
Less than 3′ (91 cm) in height.
Flowers
Yellow, in clusters of 1 to a few at stem and branch tips. Each flower is ⅜-½″ (1-1.4 cm) around, with 5 yellow petals and 5 pale green sepals, a fountain of yellow stamens, and three styles fused into one in the center. (Rarely, the number of sepals and petals may be 4 or 6.) There are in excess of 100 stamens. Flowers appear from July to August.
¼″ (6.3 mm) in size, yellow or yellow-orange, with five petals and 5-15 stamens. Beneath the petals of each flower there are somtimes green bracts that are narrower but roughly the same length, one for each petal. Blooms from July to October.
Bright yellow, star-shaped, with five petals and many yellow stamens about the length of the petals. Petals have serrated edges and small black dots on the serrations. Flowers are up to ⅞″ (2.5 cm) across.
Leaves
⅜-1½″ (1-4 cm) × ⅛-¾″ (3-20 mm), and elliptical-oblong in shape, generally rounded at leaf tips, and attached directly to the stem (sessile).
Roughly oval in shape, and attached directly to the stem (sessile). They are opposite, unlobed, ½-1½″ (1.3-3.8 cm) long and ¼-¾″ (6.3-19 mm) across.
Oval, about ⅜″ (1.2 cm) long, with smooth edges, occurring in opposing pairs.
Fruit
Capsules are ⅛-3/16″ (4-6 mm) × ⅛-3/16″ (3.5-5 mm), ellipsoid, and rounded to a tip.
1/16-⅛″ (2-3.5 mm) in length.
Range/ Zones
Habitats
Sandy forest floodplains, sandy swamps, moist to wed sandy prairies; damp, sandy, acidic areas in general
5-41″ (13-105 cm) tall, with hairless red or green stems.
Flowers
Yellow, 5-petaled flowers, densely clustered at stem tips, are ¼-½″ (8-15 mm) around. Sepals are also dotted with rows of black dots. At the center of each flower is a round central ovary, from which 3 styles extend. The tip of each style is often red. Surrounding this are more than 13 stamens. Flowers appear from May to Sep.
Leaves
Leaves are unlobed, hairless, opposite, oblong to oval elliptic, ¾-2″ (1.9-5.7 cm) long × ¼-½″ (8.3-12 mm) wide. New leaves are spotted with tiny black glands. They are typically widest somewhat past the midpoint. Leaves are usually attached to the stem (sessile).
Fruit
Upright, ovoid or teardrop-shaped capsule ⅛-¼″ (4-6.3 mm) long, reddish to deep purple.
Notice the little black dots along the edges of the petals. · 7/21/2013 · Gibbet Hill, Groton, Massachusetts · ≈ 9 × 6″ (23 × 16 cm)
6/21/2010 · Nashua River Rail Trail, Groton Center, Groton, Massachusetts · ≈ 3½ × 2½″ (9.8 × 6.6 cm)
7/13/2015 · Mt. Ascutney State Park, Ascutney, Vermont · ≈ 6 × 4″ (16 × 10 cm)