[Overview]
What is generally called torenia is Torenia fournieri (Japanese name Hana-urikusa), but interspecific hybrid cultivars have also begun to appear on the market.
An annual or perennial.
The stem has 4 ridges.
The leaves are simple and opposite, with serrations.
The flowers are borne singly in the leaf axils on the upper part of the stem, or sparsely in racemes at the stem tips.
The flower is tubular with a lipped tip; the upper lip is rounded and 2-lobed, and the lower lip is 3-lobed.
The calyx is tubular and 5-lobed, with 5 vertical ridges, and wings often appear on the ridges.
The fruit is a capsule enclosed by the enlarged calyx.
[Cultivation]
Propagate from seed or stem-tip cuttings.
The seeds are extremely fine.
When sowing, do not cover the seeds with soil, and water from the bottom.
It prefers a fertile place that is sunny, well drained, and well ventilated.
Perennial types can overwinter outdoors in regions without frost; potted plants are brought into a warm place indoors in winter.
For potted plants, water thoroughly when the soil surface dries; for plants in the ground as well, water if sunny weather continues and the soil dries out.
Apply slow-release fertilizer placed on the soil during the growing period.
Remove spent flowers promptly.
Pests and diseases include gray mold and aphids.
