Primula obconica

Japanese name: プリムラ オブコニカ
Scientific name: Primula obconica

[Overview]
Wild plants are found at elevations of 500–3,300 m and are perennials 10–20 cm tall.
They are not heat tolerant, so in Japan they are treated as annuals sown in summer to autumn.
The leaves are simple and basal, ovate, 3–14 cm long and 2.5–11 cm wide, with notched teeth on the margin.
The underside of the leaf is hairy, the hairs being glandular hairs containing a substance called primin, which often causes skin rash.
The leaves have long petioles.
The flowers are borne in umbels; the corolla is 5-lobed, and each lobe is further divided in two at the tip.

[History]
It was discovered by C. Maries in 1879 and introduced to Europe, and many garden cultivars have been developed since.
Cultivars containing almost no primin have also appeared.

[Cultivation]
Propagate from seed or by division.
The seeds need light to germinate, so do not cover them with soil; water from the bottom, and raise seeds sown in summer in airy partial shade until autumn.
It prefers fertile, well-drained soil that also retains water well.
For overwintering, it is desirable to keep it at 5°C or higher, so grow it in a pot in a sunny place indoors.
For potted plants, water thoroughly when the soil surface dries; for plants in the ground, rainfall is sufficient.
In addition to base fertilizer, apply liquid fertilizer so that fertilizer does not run out during the flowering period.
Spent flowers left on the plant can cause disease, so remove them promptly.
When the flowers have almost finished blooming, cut off the flower stalks entirely, and the next flower stalks will grow.
Pests and diseases include damping-off, Botrytis, soft rot, gray mold, cutworms, slugs, nematodes and root mites.

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