Delphinium (genus)

Japanese name: デルフィニウム
Scientific name: Delphinium

[Overview]
An annual to perennial.
Its native habitat is cool highlands, and since it cannot survive the hot, humid summers in Japan, it is treated horticulturally as an annual.
The stem is erect.
The leaves are basal and alternate, palmately lobed shallowly to deeply.
There are leaf stalks.
Long spikes or racemes are borne at the stem tips.
The flowers are bluish, with 5 showy petal-like sepals, the upper sepal having a long spur at the back.
The petals protrude small in the center of the flower.
The fruit is a follicle.

[Cultivation]
Propagate from seed.
Germination of the seed is inhibited in hot weather, so sow it in late September or later, after the lingering summer heat has passed.
It prefers fertile, well-drained, moisture-retentive, well-aerated soil.
Grow it in a sunny, airy place.
In cool regions, some plants can get through the summer if kept on the dry side in airy partial shade.
For potted plants, water thoroughly when the soil surface dries.
For plants in the ground, rainfall is sufficient.
Apply slow-release fertilizer as base fertilizer, and give additional fertilizer during the growing season.
Pests and diseases include powdery mildew and damping-off.

View this page in Japanese (日本語)