[Overview]
A perennial about 30 cm tall, but in Japan it is mainly treated as an annual.
When the plant is damaged, a white milky sap comes out.
This sap can cause skin rash and inflammation, so caution is needed.
The leaves are simple, alternate or occasionally whorled, and the leaf margins are irregularly cut or have teeth or serrations.
The flowers have long stalks, and the corolla is two-lipped or star-shaped with 5 nearly equal lobes.
The fruit is a capsule.
[Cultivation]
Propagate from seed or by stem cuttings.
When taking stem cuttings, take care not to get a rash from the milky sap that comes out when the stems and leaves are cut.
It is safest to keep it at 5°C or above for overwintering, so bring it indoors to a sunny place in winter.
It prefers slightly dry soil with good drainage and aeration.
Full sun is good from autumn to spring, but it is sensitive to stuffy conditions, so during long rainy spells and in summer let it stay cool in a partially shaded, airy place out of the rain.
For potted plants, water thoroughly after the soil dries from spring to autumn and keep on the dry side in winter; for plants in the ground, rainfall is sufficient.
Fertilize sparingly; apply a base fertilizer, and for potted plants give a small amount while watching growth, so that no fertilizer remains in midsummer.
There are no particular pests or diseases.
