Ipomoea purpurea (common morning-glory, "Marubaasagao")

Japanese name: マルバアサガオ （丸葉朝顔）
Scientific name: Ipomoea purpurea

[Overview]
A twining annual.
The vine twists to the left, branches freely, grows to about 2–3 m, and twines around other objects.
The vine has many downward-pointing hairs.
Leaves are alternate and simple, heart-shaped, 3–10 cm long, and abruptly pointed at the tip.
The leaf surface is crepe-like, sunken along the veins, and the leaf margin is entire.
Flowers are borne 5–8 at a time in the leaf axils and are funnel-shaped, 5–8 cm across.
The flower color is mainly reddish purple, but white and deep purple also occur.
The fruit is flattened-spherical and faces downward.

[History]
It was introduced around 1705 for ornament and has become naturalized, mainly in warm regions.

[Cultivation]
Propagate from seed.
It prefers sunny, well-drained soil rich in organic matter.
Seeds do not germinate at low temperatures, so sow them in May–June, when the temperature rises above 20°C.
The seed coat is hard, so make a small nick in the surface with a cutter or similar and soak the seeds in water for a day and a night; this makes the cotyledons open more easily.
Take care not to make the cut too deep, and not to damage the white part called the hilum.
Keep the seeds watered so they do not dry out until germination.
After germination, transplant to the final position when 3–4 true leaves have appeared.
Water when the soil surface dries, but in midsummer water in the morning and evening when the temperature has not risen.
In addition to base fertilizer, give diluted liquid fertilizer about once a week after transplanting.
Aphids can occur.

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