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St. Johns Wort Hypericum perforatum

Phonetic Spelling
hy-PER-ih-kum per-fuh-RAY-tum
This plant has medium severity poison characteristics.
See below
Description

St. John's Wort is a herbaceous, perennial, deciduous or evergreen shrub growing to 3 feet high by 2 feet wide. H. perforatum is one of about 400 species of Hypericum, which include herbs, shrubs and trees, with different bloom times and cultural requirements. In nature, St. John's Wort is often found in open woods, roadsides and waste places, hedge banks and grassland, and in dry sunny places, usually on calcareous soils. Introduced from Europe, it is now found throughout the United States. St. John's Wort is in flower from May to August, and the seeds ripen from July to September. This species is usually in bloom during the summer solstice (dedicated to St. John), hence the common name. The plant is self-fertile and can rapidly spread to the point where it is potentially invasive. The root pattern is rhizomatous with underground stems sending roots and shoots along their length. A single plant may produce up to 100,000 seeds per year and seeds buried in soil may last for 10 years.

St. John's Wort tolerates most soil types, including sandy, loamy, and clay soils, but prefers well-drained, moist  soil. It can grow in semi-shade (light woodland) or no shade, but full sun is best for maximum blooms. It can also tolerate drought.

Diseases, Insect Pests, and Other Plant Problems:

No serious insect or disease problems. Invasive spread can displace native species.

See this plant in the following landscapes:
Entryway Garden, Cabarrus County Extension Office
Cultivars / Varieties:
Tags:
#yellow flowers#nectar plant#dye plant#children's garden#playground plant#pollinator plant#wildflower garden#fantz#problem for cats#problem for dogs#problem for horses#yellow dye plant
 
Cultivars / Varieties:
Tags:
#yellow flowers#nectar plant#dye plant#children's garden#playground plant#pollinator plant#wildflower garden#fantz#problem for cats#problem for dogs#problem for horses#yellow dye plant
  • Attributes:
    Genus:
    Hypericum
    Species:
    perforatum
    Family:
    Hypericaceae
    Uses (Ethnobotany):
    Native Americans have been known to use this plant for medicinal purposes. Flowers can be used as a yellow dye plant.
    Life Cycle:
    Perennial
    Recommended Propagation Strategy:
    Division
    Seed
    Country Or Region Of Origin:
    Europe, North Africa, Western Asia
    Distribution:
    Throughout the United States and Canada
    Play Value:
    Attracts Pollinators
    Wildlife Food Source
    Edibility:
    Ingestion of St John's wort can reduce the effectiveness of prescription medicine.
    Dimensions:
    Height: 1 ft. 0 in. - 3 ft. 0 in.
    Width: 0 ft. 9 in. - 2 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Ground Cover
    Perennial
    Wildflower
    Woody Plant Leaf Characteristics:
    Deciduous
    Habit/Form:
    Dense
    Mounding
    Multi-stemmed
    Spreading
    Growth Rate:
    Medium
    Maintenance:
    Low
    Texture:
    Medium
  • Cultural Conditions:
    Light:
    Full sun (6 or more hours of direct sunlight a day)
    Partial Shade (Direct sunlight only part of the day, 2-6 hours)
    Soil Texture:
    Clay
    Loam (Silt)
    Sand
    Soil pH:
    Acid (<6.0)
    Alkaline (>8.0)
    Neutral (6.0-8.0)
    Soil Drainage:
    Good Drainage
    Moist
    NC Region:
    Coastal
    Mountains
    Piedmont
    USDA Plant Hardiness Zone:
    3b, 3a, 4a, 4b, 5b, 5a, 6b, 6a, 7b, 7a, 8b, 8a
  • Fruit:
    Fruit Color:
    Brown/Copper
    Display/Harvest Time:
    Fall
    Fruit Type:
    Capsule
    Fruit Description:
    Each 3-celled seed capsule is well-rounded at the base, becoming conical at its apex. Each cell of the seed capsule contain numerous seeds, which are oblong, flattened, and black. The surface of each seed is somewhat roughened by numerous small pits, rather than smooth.
  • Flowers:
    Flower Color:
    Gold/Yellow
    Flower Inflorescence:
    Cyme
    Flower Value To Gardener:
    Long Bloom Season
    Showy
    Flower Bloom Time:
    Spring
    Summer
    Flower Petals:
    4-5 petals/rays
    Flower Size:
    1-3 inches
    Flower Description:
    Yellow petals with black dots on margins; bushy stamens. Solitary or cymose, terminal or axillary. Yellow (usually) 5-petaled (rarely 4), 5 sepals (rarely 4); stamens numerous, in bundles or in showy boss. The upper stems terminate in flat-headed clusters of several flowers. Each flower is about ¾ of an inch across. There are scattered black dots along the margins of the petals.
  • Leaves:
    Woody Plant Leaf Characteristics:
    Deciduous
    Leaf Color:
    Green
    Leaf Type:
    Simple
    Leaf Arrangement:
    Opposite
    Whorled
    Leaf Shape:
    Oblong
    Leaf Margin:
    Entire
    Hairs Present:
    No
    Leaf Length:
    < 1 inch
    Leaf Width:
    < 1 inch
    Leaf Description:
    Leaves are about 1 inch long and 1/3 of an inch across. They are oblong, hairless, and sessile. The surface of these leaves is perforated by numerous translucid dots, and there are often scattered black dots along the margin of the lower surface.
  • Stem:
    Stem Color:
    Green
    Stem Is Aromatic:
    No
    Stem Cross Section:
    Round
    Stem Surface:
    Smooth (glabrous)
    Stem Description:
    Contains 2 to 4 (up to 6) ridges on newer growth, smooth and rounded on older growth.
  • Landscape:
    Landscape Location:
    Recreational Play Area
    Slope/Bank
    Woodland
    Landscape Theme:
    Children's Garden
    Pollinator Garden
    Design Feature:
    Barrier
    Mass Planting
    Attracts:
    Bees
    Pollinators
    Resistance To Challenges:
    Drought
    Poor Soil
    Problems:
    Problem for Cats
    Problem for Dogs
    Problem for Horses
  • Poisonous to Humans:
    Poison Severity:
    Medium
    Poison Symptoms:
    Skin contact with the sap, or ingestion of the plant, can cause photosensitivity in some people. Common side-effects are gastointestinal disturbances, allergic reactions and fatigue, ulcerative and exudative dermatitis.
    Poison Toxic Principle:
    Hypericin
    Causes Contact Dermatitis:
    Yes
    Poison Part:
    Leaves
    Sap/Juice