Specialty & folk herb · Growing guide
St. John’s Wort
Hypericum perforatum · Hypericaceae family
St. John’s Wort is an upright specialty & folk herb grown for specialty herb collection, botanical education, and pollinator planting. Use this guide to match its light, water, soil, space, seasonal care, and safety needs.
Guide status Exact ranges are a catalog starting point. Check the plant label, cultivar, region, and linked sources before planting.
- Reliable light
- Full to part sun
- Water pattern
- Moderate
- Mature size
- 36 × 24 in
- Final spacing
- 24 in
- Season
- perennial
Plant identity, types & settings
One plant guide. Clear details underneath.
St. John’s Wort is the plant identity. Container, landscape, cutting, indoor, hydroponic, and harvest labels describe ways to grow it; they are not additional plant or cultivar names.
Ways to grow it
These are garden or production settings—not cultivar names and not extra plants.
Contained Container
Use a dedicated container to control roots and prevent accidental mixing with culinary herbs.
- Mature size
- 28 × 17 in
- Spacing
- 13 in
- Container
- 4+ gal · 16+ in deep
Garden Specimen
Use a labeled permanent position and manage seed or rhizome spread.
- Mature size
- 36 × 24 in
- Spacing
- 24 in
- Container
- 5+ gal · 16+ in deep
01 · Light & site
Give it the light its growth depends on.
Full to part sun, with roughly 4 to 7 hours of useful light. Perennial timing, dormancy, and winter survival are climate- and cultivar-specific.
02 · Water & soil
Keep roots supplied without trapping water.
Water deeply when the active root zone begins to dry.
- Soil
- Loose, organic, species-appropriate garden soil
- Drainage
- Well drained
- pH
- Species-specific; verify the grower label and linked guidance
03 · Spacing & roots
Make room for the mature plant.
Space plants about 24 inches apart. Expect a mature plant around 36 inches tall by 24 inches wide.
fibrous to rhizomatous herbaceous root system. Container figures are a planning floor, not a claim that long-term container culture is ideal.
04 · Start
Begin with the method that protects establishment.
Use the species-appropriate method—seed, cutting, division, bulb, tuber, or a healthy transplant—and follow the plant label for timing.
05 · Care
Support healthy growth through the season.
Usually self-supporting; contain spreading species. Add a discreet stake only if wind, bloom weight, or an exposed site makes it necessary.
- Upkeep
- High
- Feeding
- Moderate
- Watch for
- Species-specific insects, Crowding-related disease, Moisture stress
06 · Flower or harvest
Harvest and flowering
75–180 days to the first expected harvest, bloom, or established display; perennials may need additional seasons to settle. Grow it for botanical interest and keep it clearly labeled. Historical or cultural use does not establish safe ingestion or medical benefit.
07 · Safety
Know the cautions before you place or use it.
- Historical use is not evidence of safety or effectiveness.
- Known for numerous clinically important medication interactions and photosensitivity risk.
- Listed as invasive or noxious in multiple regions; check local rules.
- This plant may interact with medicines; ask a qualified clinician or pharmacist before any internal use.
- Spread or invasiveness risk is high; check local rules and contain seed or runners.
Historical or cultural association does not establish safety or medical benefit. This guide does not provide treatment, dosing, or ingestion advice.
08 · Sources
Check the evidence behind the guide.
Guide record: Editorial review pending; generated 2026-08-10. Region, cultivar, regulations, and current product labels can change the right decision.
Working checklist