St John's wort
A grassland perennial with bright yellow flowers whose most useful feature is what it does not offer: no nectar at all, and a great deal of pollen. Bees buzz the anthers to release it, which makes St John's wort a clear demonstration of why nectar and pollen have to be rated separately.
Where not to plant it
A serious invasive weed of rangeland in North America, Australia and South Africa, where it is toxic to grazing livestock and displaces pasture. Biological control with introduced beetles has been used for decades.
Caution
St John's wort has well-documented interactions with a great many prescription medicines, including hormonal contraceptives, anticoagulants and antidepressants, through induction of liver enzymes. This concerns herbal preparations of the plant, not honey — and there is no St John's wort honey, because the plant produces no nectar.
Value to bees
- Nectar
- None
- Pollen
- Very high
- As a honey crop
- Not a honey source
- Which bees, and why
- Bees visit for pollen alone and buzz the anthers to release it. Honey bees, which cannot buzz, work it less efficiently than bumblebees and solitary bees do.
Fully open flowers with completely exposed anthers, and no nectar at all to reach.
- Worth knowing
- No nectar whatsoever and an outstanding pollen source. A single bee-friendliness score would misrepresent this plant in either direction.
Flowering
- In flower
- June to September (northern hemisphere)
A long summer season.
Growing it
- Conditions
- Full sun on well-drained, even poor, soil. Drought-tolerant and undemanding.
- Size
- 40-80 cm tall.
- Native range
- Europe, western Asia and North Africa, in grassland, roadside and open woodland. Naturalised and invasive in North America and Australia.
- Suits
- Meadow or wildflower area, Large gardens, Small gardens
- Self-seeds freely; deadhead if that is unwelcome.
- Better in a meadow or rough area than in a tidy border.
- Do not plant in North America or Australia, where it is a serious pasture weed.
What it looks like
An upright perennial with small oval leaves marked with translucent dots visible against the light, and flat clusters of bright yellow five-petalled flowers with a boss of long stamens.
Sources
- Field Guide to the Bees of Great Britain and Ireland — Bloomsbury (2015) · Field guide
- Assessment Report on Pollinators, Pollination and Food Production — Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) (2016) · Systematic review Link
How sources are selected and weighted is set out in the sources and evidence policy.
Guides covering this plant
- Pollen plants explainedPollen is protein and it is what bee larvae are made of. A garden with abundant nectar and no pollen supports adult bees and produces no new ones.
- How to make a garden genuinely useful to beesMost bee-friendly advice covers flowers in June, which is the one thing bees are least short of. The gaps are at the ends of the year — and half the problem is not flowers at all.
- Long-flowering plants for beesA plant in flower for five months does the work of three plants in flower for six weeks, and removes the timing problem that defeats most bee planting. These are the ones that keep going.
Tools for planning planting
- Flowering calendar
What should I plant so that something is always in flower for bees?
- Bee-friendly garden planner
What should I plant in the space I actually have?
- Plant recommendation tool
Which plant fills this specific gap?