- Start the seeds indoors from February–May.
- Sow the seeds thinly on the surface of moist, well-drained seed compost and lightly cover.
- Keep at a temperature of 18-22c until germination occurs.
- Seeds will usually germinate within 14-28 days.
- Once seedlings are large enough to handle, transplant them into individual pots.
- Grow on in bright light and cooler conditions, keeping the compost just moist.
- Gradually acclimatise the plants to outdoor conditions before planting out.
- Plant out after the risk of frost has passed into their final flowering position.
- Space plants 45-60 cm apart to allow room for mature clumps.
- Water regularly during dry spells until established, but avoid waterlogging.
- Remove spent flower spikes after flowering and cut back old foliage in spring to encourage fresh growth.





