PlantSowGrow
How to grow Iris reticulata
Iris reticulata 'Harmony'
Jewel-like, royal-blue dwarf irises with yellow flashes in February, often through snow. Perfect for pots, gravel and the front of borders.
At a glance: Sow early September to mid October.
When to sow, plant and harvest
Timed for a typical UK garden (last frost mid-April). The app uses your own town's frost dates.
Growing Iris reticulata: what it needs
- Light
- Full sun · 6+ hours a day
- Watering
- Water pots in dry spells while in leaf; keep drier when dormant
- Soil
- Well-drained soil or bulb compost
- Spacing
- 5 cm
- Height
- 10–15 cm
- In pots
- Grows well in containers
- Feeding
- Feed with a high-potash liquid feed as flowers fade
- Hardiness
- USDA zones 4–9
Step by step
- Early September – mid October · 6 weeks before the first autumn frost
Plant Bulbs
Plant 10 cm deep and 5 cm apart, pointy end up, in well-drained soil or pots. Water in.
- 100–150 days after “Plant Bulbs” · Mid December – early February
Look for Shoots
Green shoots should be showing. Keep pots moist but not wet and watch for slugs on young leaves.
Every year
- FebruaryIn Flower
Your bulbs should be in flower — a good moment for a journal photo.
- MarchDeadhead and Feed
Snap off faded flower heads (not the leaves) and give a high-potash feed to build up the bulb for next year.
- AprilLet the Leaves Die Back
Leave the foliage for at least six weeks after flowering, until it yellows — don't knot or cut it. Then tidy it away.
