Japanese name: シロバナムシヨケギク（白花虫除菊） Scientific name:Tanacetum cinerariifolium
[Overview]
A perennial 45–100 cm tall.
The leaves are alternate and deeply bipinnately divided.
Capitula about 3 cm across are borne at the tips of long flower stalks.
The ray florets are white and the central tubular florets are yellow.
The fruit is an achene.
[History]
It was introduced from America in the 18th year of the Meiji era.
[Uses]
It contains pyrethrin, an insecticidal compound, and was cultivated so that the flower heads could be used as a raw material for mosquito coils.
[Cultivation]
Propagate from seed or by division.
A sunny, well-drained, well-ventilated, fertile soil is suitable.
In poor sun it becomes leggy and flowers poorly.
Stuffiness in summer weakens the plant, so take care to avoid excess humidity.
Water after the soil surface has dried.
If base fertilizer is applied, no further fertilizing is particularly necessary.
Overgrown stems and leaves make the interior stuffy, so thin out crowded parts as appropriate.
There are no particular pests or diseases.
