Herb
St John's wort
Hypericum perforatum
St John's wort is a hardy perennial herb with bright yellow flowers traditionally used for medicinal purposes. It thrives in sunny locations with minimal care and can spread vigorously.
Full sun
Low
Well-draining, tolerates poor to average soil, prefers slightly alkaline pH
Very easy
Yes
Flowers, leaves (medicinal use)
- 1Sow seeds in spring after last frost or start indoors 6-8 weeks earlier; barely cover seeds as they need light to germinate
- 2Space plants 12-18 inches apart in full sun; they tolerate drought once established
- 3Pinch back young plants to encourage bushier growth; flowers bloom from June to September
- 4Requires minimal fertilization; too much feeding reduces medicinal potency
- 5Divide established clumps every 3-4 years to maintain vigor
Season
Plant in spring after last frost; blooms mid to late summer; perennial returns year after year in zones 5-9
Rust fungus
Remove affected leaves promptly and ensure good air circulation between plants
Aphids
Spray with strong water jets or apply insecticidal soap to affected areas
Can cause photosensitivity in some individuals; interacts with many medications including antidepressants. Consult healthcare provider before medicinal use. Considered invasive in some regions.
This plant guide is generated by AI from publicly available horticultural knowledge. Before eating any part of a plant, cross-check with a trusted local source or grower. Toxicity and edibility vary by variety, growing conditions and individual sensitivity.
Where to source
Get growing in United Kingdom
Shop local first
The best plants come from a real nursery, and the best trowel comes from the old-fashioned ironmonger down the road — people who know their stock and can advise. Try local first, both for the plant and the kit. It keeps small growers and small hardware shops alive.
Searching near London
For pots, compost, seed trays, twine and other kit — Amazon has the essentials if the local option isn't right. Not a plant nursery; use the local map above for the plant itself.
Some links may earn us a small commission — at no cost to you.