How to Grow Stinking Iris
Iris foetidissima
Iris foetidissima thrives in dry shade where little else will grow — under trees, by north-facing walls, or in dense shrub borders. Its small purple flowers in June are modest, but the real show is the bright orange-scarlet seed pods that split open in autumn and persist through winter. Plant in any soil including chalk, water well to establish, then leave it alone. Cut back tatty leaves in early spring and mulch lightly. It slowly forms handsome evergreen clumps with virtually no maintenance.
Yearly Lifecycle
Care Essentials
No feeding required in most soils. On very poor, sandy soil a light mulch of garden compost in spring is sufficient.
Watch For
- Slugs on young spring growth
- Vine weevil larvae (containers)
- Rhizome rot in waterlogged soil
Companions
Hellebore, Epimedium, Ferns, Vinca minor
Pet Safety
Care Requirements
Light
Shade to part shade; tolerates dry shade under trees
Tolerates deep shade, dry shade, and partial shade. Also grows in sun if the soil is kept moist, but its greatest value is in shaded spots where little else thrives.
Watering
Drought-tolerant once established; water in first year only
Drought-tolerant once established. Water well during the first season. In subsequent years, rainfall is usually sufficient even in dry shade under tree canopies.
Fertilizing
No feeding needed; light compost mulch on poor soils
No feeding required on most soils. A light top-dressing of garden compost in spring benefits plants on very poor soils.
Pruning
Tidy in early spring; remove old seed stems in late winter
Remove damaged or brown leaves in early spring. Cut spent seed stems to ground level in late winter once the orange seed display is over. No summer pruning needed.
Growing Tips
Dry shade specialist
This is one of very few ornamentals that genuinely thrives in dry shade under trees or beside north-facing walls. Once established, it needs no additional watering even in summer drought.
Leave seed pods for winter display
The bright orange seeds inside split pods are the plant's main attraction. Do not deadhead or cut back seed stems in autumn — leave them standing through winter for colour and wildlife interest.
Smells when bruised, not when left alone
The foliage releases an unpleasant smell only when crushed or cut. In the garden it is not noticeable — the common name is misleading. Handle with gloves when pruning.
Pests & Diseases
Pest Slugs and Snails
Identification: Ragged holes in young leaves; slime trails on foliage and soil surface
- Apply biological nematode control (Phasmarhabditis hermaphrodita) in spring when soil is above 5°C
- Set beer traps around new growth
- Scatter crushed eggshell or sharp grit around crowns
- Ferric phosphate slug pellets (wildlife-safe)
Pest Vine Weevil
Identification: Notched leaf margins (adult feeding); wilting and collapse (larval root damage)
- Apply Steinernema kraussei nematodes to compost in autumn or spring
- Inspect roots when repotting and remove any white grubs by hand
- Imidacloprid or thiacloprid drench (containers only)
Disease Rhizome Rot
Symptoms: Soft, foul-smelling rot at base of leaves; foliage yellows and collapses; slimy tissue at crown
Treatment: Dig up plant, cut away all rotten tissue with a clean knife, dust with sulphur powder, allow to dry before replanting in better-drained soil
Prevention: Avoid planting in waterlogged spots; do not over-mulch the crown; ensure reasonable drainage even in shade
Spacing & Planting
| Plant spacing | 40 cm |
| Row spacing | 45 cm |
| Mature height | 55 cm |
| Mature spread | 40 cm |
Slowly clump-forming. Allow 40 cm between plants; spreads gradually but is not invasive.
