[Overview]
An annual.
The leaves are simple and opposite, with entire margins.
A single flower head is borne at the end of each branch, and flower colors include almost every color except blue.
The fruit is an achene.
[Cultivation]
Propagate from seed or by stem cuttings.
It prefers a sunny, airy site with soil that is well drained, moisture-retentive and well aerated.
In poor light, flowering becomes poor or the flowers become smaller.
Splashing mud from rain or watering makes disease more likely, so for plants in the ground it is good to mulch around the base with bark compost or similar.
Water thoroughly when the soil surface dries, and it is best to water as close to the base as possible to prevent mud from splashing back.
Apply base fertilizer, and continue until the flowering period with chemical fertilizer about once a month or liquid fertilizer about once every 10 days.
After flowering, cut back from the topmost bud to a few nodes below; side shoots will then grow and a second flush of flowers can be enjoyed.
Pests and diseases include bacterial leaf spot, gray mold, powdery mildew, damping-off, aphids and spider mites.
