(Hypericum perforatum 'St. John's Wort')
St. John's Wort is an introduced, short-lived, perennial, woody shrub that is native from Macaronesia to SE China, but can be found growing in open woods, hedge banks, grasslands, and roadsides throughout the United States. At maturity, this plant reach the height of 2' and features a spreading mound of multi smooth, green, round stems and 1” long, 1/3” wide, hairless, green oblong leaves, and 3/4”, 5 petal, goldish/yellow flowers that have black dots scattered across the edges. This plant can be grown in a container, attracts bees, is a host plant for Gray Hairstreak butterflies, is resistant to deer and rabbits, makes dye, and is both edible and medicinal!
Culinary & Medicinal
Variety: St. John's Wort
Also Known As: Common St. John's-wort, Goatweed, Klamath Weed, and St. Johns Wort.
Native to: Afghanistan, Albania, Algeria, Altay, Austria, Azores, Baleares, Baltic States, Belarus, Belgium, Bulgaria, Canary Is., Central European Rus, China North-Central, China South-Central, China Southeast, Corse, Cyprus, Czechoslovakia, Denmark, East Aegean Is., East European Russia, Finland, France, Germany, Great Britain, Greece, Hungary, Iran, Iraq, Ireland, Italy, Kazakhstan, Kirgizstan, Krasnoyarsk, Kriti, Krym, Lebanon-Syria, Madeira, Morocco, Netherlands, North Caucasus, Northwest European R, Norway, Pakistan, Palestine, Poland, Portugal, Qinghai, Romania, Sardegna, Saudi Arabia, Sicilia, South European Russi, Spain, Sudan, Sweden, Switzerland, Tadzhikistan, Transcaucasus, Tunisia, Turkey, Turkey-in-Europe, Turkmenistan, Ukraine, Uzbekistan, West Himalaya, West Siberia, Xinjiang, Yugoslavia.
Introduced into: Alabama, Argentina Northeast, Argentina South, Arkansas, Brazil Southeast, British Columbia, Buryatiya, California, Cape Provinces, Chile South, Colorado, Connecticut, Cuba, Delaware, District of Columbia, Haiti, Hawaii, Idaho, Illinois, Indiana, Iowa, Irkutsk, Japan, Juan Fernández Is., Kansas, Kentucky, Korea, Lesotho, Maine, Manitoba, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Montana, Nebraska, Nevada, New Brunswick, New Hampshire, New Jersey, New Mexico, New South Wales, New York, New Zealand North, New Zealand South, Newfoundland, North Carolina, North Dakota, Nova Scotia, Ohio, Oklahoma, Ontario, Oregon, Pennsylvania, Primorye, Prince Edward I., Québec, Rhode I., Réunion, South Australia, South Carolina, South Dakota, Tennessee, Texas, Uruguay, Vermont, Victoria, Virginia, Washington, West Virginia, Western Australia, Wisconsin, Wyoming.
Grown as: Perennial
Maturity (Blooms): Summer - June through September
Light: Full sun in the North, shaded area in the South.
Water: Medium when young, drought tolerant when mature.
Soil Moisture: Medium moisture.
Attracts Beneficial Insects?: Yes. Attracts bees, is a host plant for Gray Hairstreak butterflies, is resistant to deer and rabbits. However, it can be a problem for cats, dogs, and livestock.
Containers?: Yes. Due to medium growth rate nature of this plant, it is easiest to contain by growing in a pot or indoors. An 8 to 10-inch pot is suitable for a single plant.
Sow Depth: On soil surface
USDA Zone: 3-8
Produces: a spreading mound of multi smooth, green, round stems and 1” long, 1/3” wide, hairless, green oblong leaves, and 3/4”, 5 petal, goldish/yellow flowers that have black dots scattered across the edges.
Garden Uses: Slope/Bank, Woodlands, Pollinator Garden, Barrier, Mass Plantings.
Known hazards of Hypericum perforatum: Skin contact with the sap, or ingestion of the plant, can cause photosensitivity in some people.
Poison Severity: Medium
Causes Contact Dermatitis: Yes
Poison Part: Young Leaves, Sap/Juice.
To plant St. John's Wort in the spring time, the seeds will need to be started indoors 6-8 weeks before your areas last frost date.
Germinating St. John's Wort Seeds:
1) Soak seeds for a few hours or up to overnight in warm water to hasten germination.
2) Fill seed starting trays to within 1/4 to 1/2 inch of the rim with moist soil mix.
3) Firm the surface with the back of your fingers, then scatter seeds evenly over the medium.
4) Press the seeds into the soil but do not cover fully add a label with the plant name and date.
5) Cover the finished pots with plastic and set them in a bright place or under lights at a temperature of 60-70˚F degrees Fahrenheit.
6) Keep the soil moist as the seedlings sprout and develop.
7) Thin when the seedlings are 2-3", keeping the healthiest looking plants.
Average Germ Time: 10-20 days
Light Required: Yes
Depth: Do not cover the seed but press into the soil
Moisture: Keep seed moist until germination
Direct sow your seeds into the garden in late autumn before the last frost 18-24" apart. St. John's Wort can tolerate almost any soil but prefers a moist, good draining soil that has a pH between 5.8 and 7.2. If you live in the North, you will need to plant your seeds in a location that receives full sun. If you live in the South, you will need to plant your seeds in an area that will receive part shade.
Transplant your seedlings into the garden once the soil has warmed after all dangers of frost. St. John's Wort can tolerate almost any soil but prefers a moist, good draining soil that has a pH between 5.8 and 7.2. In colder areas, St. John's Wort appreciate full sunshine. In hotter climates, it will do best with afternoon shade to provide shelter from the intense heat. Dig your holes as deep as the pots you are transplanting from and keep a spacing of 18-24" between seedlings. Your soil will need to maintain a medium moisture until your plants mature which then they will be able to tolerate drought..
When outdoor temp: 63˚F to 82˚F.
Temperature and Humidity: St. John's Wort can routinely handle the wide range of temperatures across USDA zones 3 to 8. It is known to survive down to minus 10˚F degrees Fahrenheit, but prefers temps between 68-78˚F.
Fertilizer: St. John's wort requires very little fertilizing. Usually, no additional fertilization is needed after the initial planting, unless obvious symptoms of slow growth appear. If that happens, apply some low-concentration balanced compound fertilizer (10-10-10 NPK ratio).
Pruning: Prune plants in early spring to encourage new stems. The plant’s flowers only develop on new growth.