Herb · Hypericaceae family
St. John's wort
Hypericum perforatum
In short a 10-second read
spacing 11¾ in
Where to plant and how much to water
Sun, soil and water.
It grows best in full sun to part shade, in dry to average soil.
Sun
Soil
Watering
Frost
How much space it takes
Mature size.
The mature plant next to a person (69 in).
Plant 11¾ in apart.
Reaches maturity in about 2–5 years. The final size depends on the cultivar and the spot — we give the range from smallest to largest.
Calendar
Through the year.
Typical for a temperate climate (four seasons). The line shows the current month.
The year at a glance
Flowers
June–August · yellow
Sowing
sow indoors: February–April; direct sowing: March–April, August
Planting
transplant outdoors: April–June
What to plant now (February) full list in February (20) →What to plant now (March) full list in March (284) →What to plant now (April) full list in April (323) →What to plant now (May) full list in May (185) →What to plant now (June) full list in June (58) →What to plant now (August) full list in August (25) →
Frequently asked
Quick answers.
When does St. John's wort flower?
In June–August; the flowers are yellow.
When do I sow St. John's wort?
In February–April, August (sow indoors, direct sowing).
Does St. John's wort tolerate shade?
It tolerates part shade (3–6 hours of sun), but not full shade.
How much space does St. John's wort need?
At maturity 9⅞ in–1 ft 11⅝ in wide and 11¾ in–2 ft 11⅜ in tall; recommended spacing 11¾ in.
Sources (13) Checked 19 October 2026
- plants.ces.ncsu.edu
- missouribotanicalgarden.org
- rhs.org.uk
- pladias.cz
- api.gbif.org
- dobrasemena.cz
- kraeuter-und-duftpflanzen.de
- ema.europa.eu 2
- yardandgarden.extension.iastate.edu
- Invasive plant lists — this species is not on them: EASIN, EASIN 2, Slovakia
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