Gomphrena haageana (Rio Grande globe amaranth, "Amerikasennichiko")

Japanese name: アメリカセンニチコウ
Scientific name: Gomphrena haageana

[Overview]
A perennial 20–70 cm tall.
It has little cold tolerance, so in Japan it is treated almost as an annual.
The whole plant is covered with coarse hairs.
The leaves are simple and opposite, linear-elliptic, about 3–8 cm long and 0.3–1 cm wide.
Head-like inflorescences 2–2.5 cm across are borne at the stem tips, with 2 leaf-like bracts beneath each inflorescence.
The flowers are very small, and the colored, dry bracts are conspicuous.
The bracts are red, orange, yellow and so on, and do not fade for a long time.
The fruit is a utricle.

[Cultivation]
Propagate from seed or by stem cuttings.
The optimum temperature for germination is 20–25 °C.
The seed surface is covered with cottony hairs, so rub them off thoroughly before sowing.
It can overwinter if kept at 3 °C or above, so bring potted plants indoors to a bright window in winter.
It is not very particular about soil as long as the site is sunny, well drained and well ventilated.
In poor light, flowering is poor.
It prefers a somewhat dry place and dislikes humidity, so move potted plants out of the rain during long rainy spells.
When watering, take care to avoid excess moisture; for potted plants, water thoroughly when the soil surface dries.
For plants in the ground, rainfall is sufficient.
Fertilizing is not particularly necessary if basal fertilizer is thoroughly dug in.
Pests and diseases include damping-off and spider mites.
Damping-off occurs especially easily in young seedlings.

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