Calendula officinalis (pot marigold, "Tokinsenka")

Japanese name: トウキンセンカ （唐金盞花）
Scientific name: Calendula officinalis

[Overview]
An annual or biennial 30–60 cm tall.
The stems and leaves bear many soft, somewhat sticky glandular hairs.
The stem is erect and branches well.
The leaves are alternate, broadly elliptical to lanceolate, 5–18 cm long, with entire margins or very low teeth.
The lower leaves are spatulate.
A single flower head 10 cm across is borne at the tip of the flower stalk, yellow to deep orange.
The flowers open during the day and close at night.
The fruit is an achene without a pappus, strongly curved like the letter C, with many protrusions on the back.

[Uses]
The flowers have been used for medicine, dye and other purposes since ancient Greek times.
The flowers and leaves are also edible.

[Cultivation]
Propagate from seed.
It is easy to grow.
It prefers a site that is sunny, well drained and moisture-retentive.
Poor sunlight reduces flowering.
It grows poorly in acidic soil and prefers slightly alkaline soil.
It is cold tolerant, but frost and snow damage the leaves, so frost protection may be given.
Water thoroughly when the soil surface dries.
If base fertilizer is applied, almost no further fertilizer is needed.
Setting seed tires the plant, so pick off spent flowers promptly after flowering.
Pests and diseases include powdery mildew, cutworms and aphids.

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