This caudiciform species comes from China and is very easy to grow. It can be grown outside in the garden in the summer, or just as easily in a pot. It can take a little bit of frost, especially if the soil is very sandy and well-drained. If you do not have this sort of soil, it is advisable to take them out before the winter and treat them as you would Dahlia tubers. The tubers are potted up in spring and can be either buried completely or half above ground so you can still see the tuber (see photo below). The plant prefers cool conditions (10-18°C); if the temperatures are too high (for instance, if you keep them in a greenhouse where the day temperatures get above 25°C), the flowers can become misformed.
The flowering period is from May to August and the colour of the flowers can be pink or white; the variety show in the picture is ‘Snowtop’. This genus does also have a yellow-flowered species, Incarvillea lutea, but that is a very rare sort.
Seed collected one year can be sown the following spring. The plant will form a tuber that first year and will flower the following year, so two years after collecting the seed. It is a relatively pest-free plant, but watch out for greenfly.

Incarvillea delavayii Snowtop tuber

Incarvillea delavayii Snowtop flower