Incarvillea are hardy to around -10C and can be planted directly outside in spring in most areas. If spring temperatures are cooler than -10C, they can be potted up and grown on in a cool greenhouse first.
— Plant the tubers into temporary pots in spring and grow-on in a sheltered position to transplant later when established. Alternatively, you can plant them directly into a well-dug, weed-free space in borders providing the soil is not frozen.
— Choose a position which receives full sun.
— Plant the tubers 5-10cm deep with any buds or shoots facing upwards. If they are already in leaf, the leaves should be exposed above the soil surface.
— Space the plants 15-20cm apart.
— Water-in after planting and keep hydrated when in growth.