How to Grow Sainfoin
Onobrychis viciifolia
Sainfoin is a deep-rooted perennial legume producing dense spikes of vivid pink pea-flowers beloved by bees. Plant in full sun on poor, chalky, or limestone soil — it absolutely thrives on the alkaline, free-draining conditions that most plants dislike. Fixes its own nitrogen so never needs feeding. Extremely drought-tolerant once its deep tap root is established. One of the single best plants for pollinators in a temperate garden, with nectar sugar concentrations among the highest of any British wildflower.
Yearly Lifecycle
Care Essentials
No feeding required. Sainfoin is a nitrogen-fixing legume that fertilises itself and improves the soil around it. Feeding disrupts nodule formation and can actually reduce vigour.
Watch For
- Aphids on flower spikes
- Crown rot in heavy wet soil
- Slug damage on young growth
Care Requirements
Light
Full sun essential
Sainfoin must have full sun. It will not thrive in shade or partial shade and becomes sparse and prone to disease if light is insufficient.
Watering
Drought-tolerant once established
Young plants need watering in dry spells during their first season. Once the deep tap root is established — usually by the second year — sainfoin is remarkably drought-resistant.
Fertilizing
Never feed
As a nitrogen-fixing legume, sainfoin makes its own fertiliser. Any additional feeding upsets the root nodule balance and reduces the plant's self-sufficiency.
Pruning
Cut back after flowering to encourage regrowth
After the main flowering flush, cut stems back by half to promote a second flush of flowers and keep plants compact. Remove dead stems in autumn.
