St. John's Wort Growing Guide
Growing St. John's Wort is easier than you think. This guide walks you through everything you need — from planting your first seed to harvesting.
At a Glance
Difficulty
Easy
Category
Herb
Sun Exposure
Full Sun
Frost Tolerance
Frost Hardy
Cold Hardiness
Survives to -29°C
Plant Family
Hypericaceae
Growing Season
Warm Season
Plant Lifecycle
Perennial
Also grows well as
How to Start It
★ Recommended for beginners
Lift and split the spreading clump in spring; replant vigorous pieces. The quickest route, and it keeps the plant in bounds.
Grown for its yellow midsummer flowers (traditionally harvested around St John's Day) used in mood remedies. NOTE: it spreads by runners and seed and is considered invasive/weedy in some regions, and it's toxic to grazing livestock — site it thoughtfully and deadhead to contain it.
When To Start
First Chance to Plant
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Last Chance to Plant
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When should you plant St. John's Wort?
Your planting dates depend on your local climate. Sign up and add your location to unlock personalized dates.
Your St. John's Wort Planting Window
Start planting
May 15, 2026
Last chance
Sep 10, 2026
The Journey Ahead
St. John's Wort's Lifecycle
Seedling
Mature Plant
Seed Production
Step 1
Prepare Your Space
0.1 cm
Seeding Depth
45 cm
Plant Spacing
60 cm
Row Spacing
1
Plants / Sq Ft
Vertical Growing
No.
Succession Planting
No.
Good Companions
Bad Companions
Step 2
Planting & Sprouting
Expect sprouts in 14–28 days
Growing Tips
- 1St John's wort is unkillable in full sun and poor soil.
- 2Because it spreads readily and is toxic to livestock, keep it away from pasture, deadhead to stop self-seeding, and divide it to keep it contained.
Seedling Phase
Step 3
Growth & Maturity
70 cm
Mature Height
60 cm
Mature Width
Pests to Watch For
Diseases to Watch For
Mature Plant
Step 4
Harvesting
Harvest Window
30 days
When to Pick
Harvest the flowering tops at peak bloom in midsummer
How to Harvest
- 1Snip the flowering tops when the most flowers are open, around midsummer.
- 2The buds and flowers stain red when crushed — that red oil is the active part.
Step 5
Saving Seeds
How to Save Seeds
Collect the small dry seed capsules in late summer and shake out the fine seed.
Seed Production
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