Asclepias curassavica f. flaviflora (tropical milkweed, "Kibanatowata")

Japanese name: キバナトウワタ
Scientific name: Asclepias curassavica f. flaviflora

[Overview]
An evergreen perennial or subshrub 0.3–2 m tall, but because it is sensitive to cold it is treated as an annual in Japan.
A milky white sap comes out when the stems or leaves are damaged.
The stems have coarse hairs.
The leaves are simple and opposite, oblong-lanceolate, 5–10 cm long, with entire margins.
Umbel-like cymes at the stem tips and leaf axils bear 10–20 yellow to orange flowers.
The corolla is 5-lobed and strongly reflexed, with a yellow corona that has needle-like projections.
The fruit is a spindle-shaped follicle 5–10 cm long; when ripe it releases many seeds with long silky hairs.

[Uses]
Although a poisonous plant, the flowers, leaves and roots are used medicinally.

[Cultivation]
Propagate from seed or by stem cuttings.
The optimum germination temperature is high, 20–25°C.
If grown in a pot and brought into a warm room in winter, it can be cultivated as a perennial.
It prefers a sunny, well-drained, fertile site.
For potted plants, water thoroughly when the soil surface dries; for plants in the ground, rainfall is sufficient.
It dislikes excess moisture, so take care not to overwater.
If overwintering it, keep it on the dry side in winter.
Fertilizer is not particularly necessary for plants in the ground; for potted plants, apply slow-release fertilizer regularly from spring to autumn.
The plant grows tall, so set up a stake to keep it from falling over.
Pests include spider mites and aphids.

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