Oenothera stricta ("Matsuyoigusa")

Japanese name: マツヨイグサ （待宵草）
Scientific name: Oenothera stricta

[Overview]
An annual or biennial 30–100 cm tall, growing in damp, disturbed places such as seashores and riverbeds.
The stem is usually erect and sometimes branched.
There are basal leaves and stem leaves.
The stem leaves are simple and alternate, lanceolate to narrowly elliptic, about 6–10 cm long and 0.6–1.2 cm wide, with shallow serrations on the margin.
The leaves on the stem are sessile.
The flowers are borne singly in the leaf axils in the upper part of the stem; they are yellow with 4 petals, about 3–5 cm across, and open in the evening.
There is one red spot at the base of each petal, and the flowers turn reddish as they wilt.
The calyx is often tinged with red.
The fruit is a cylindrical capsule 3–4 cm long, slightly thickened toward the tip, with sparse hairs.

[History]
It was brought to Japan by a Dutch ship during the Kaei era (1848–1854).

[Cultivation]
Propagate from seed.
It dislikes being transplanted, so sow directly where it is to be planted, or sow in pots and transplant while the seedlings are young.
It prefers sunny, well-drained soil.
For potted plants, water thoroughly when the soil surface dries; for plants in the ground, rainfall is sufficient unless summer brings a long spell of sunny weather and the soil becomes severely dry.
Too much fertilizer produces only leaves, so use it sparingly; for potted plants, in addition to base fertilizer, place a small amount of slow-release fertilizer on the soil in spring.
Plants in the ground need no particular fertilizing.
There are no particular pests or diseases.

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