The Japanese iris enriches every pond bank with elegant grass-look leaves and noble blue flowers. It is robust and easy to care for.
Profile of Japanese iris:
Scientific name: Iris laevigata
Plant family: iris family (Iridaceae)
Other names: rabbit-ear iris, kakitsubata
Sowing time: Spring
Planting time: Spring or Autumn
Flowering period: June to July
Soil quality: moist to water, nutritious, humus rich, loamy
These information are for temperate climate!
Use in: bouquets, group planting, pond planting, natural garden water garden, park
Winter hardiness: USDA Plant Hardiness Zones: 5
Bee and insect friendly: yes
Plant characteristics and classification of Japanese iris
Plant order, origin and occurrence of Japanese iris
The Japanese iris (Iris laevigata) from the iris family (Iridaceae) is native to China, Manchuria, Korea and Japan. It grows in the wild on moist to swampy soils. The Japanese in particular worship the plant very much. It has been cared for in their gardens for centuries.
Characteristics of Japanese iris
Like the water lily (Iris pseudacorus), the hardy Japanese iris spreads with the help of rhizomes. Their unbranched, sometimes one-time branched flower stems grow between 40 and 100 cm (15 and 40 in) in height. They are surrounded by long sword-shaped leaves.
The deciduous leaves of Iris laevigata stand for a natural and graceful look: their long and 1.5 to 4 cm (0.6 to 1.6 in) wide, sword-shaped leaf blades without a central rib grow around the stems at the same height. Sometimes, like grass, they outgrow the stems.
The iris owes its botanical name to its incomparably beautiful flowers. In particular, the variety of colors of the iris inspired the botanists to name the genus after the Greek goddess of the rainbow, Iris. The petals of the Japanese iris unfold in a perfect shade of blue from June to July. Meanwhile, there are also pretty white and pink varieties available. Each stem has one to three flowers. The flowers, which are up to 10 centimeters (4 inches) in size, are composed of six bracts. They are divided into three hanging and three upright leaves.
The rabbit-ear iris forms yellowish-brown capsule fruits. Dried up, they decorate the pond landscape in the cold months.
Japanese iris – cultivation and care
The Japanese iris prefers moist to wet and sunny locations.
It thrives best when it is about 10 to 20 cm (4 to 8 in) deep in the water. The soil should be humus-rich and lime-deficient.
You can propagate the wild form of Japanese iris via seeds. However, this method takes time and is difficult.
The division of the rhizome is therefore the most practical method of propagation both for the wild species Iris laevigata and for the garden varieties.
If you recognize that your iris is bare from the inside or gets too close to its neighbors, you can pick up its rhizomes, divide them and replant them two to three cm (1 in) deep in the ground. The best time for this is spring, but also works in autumn. It is best to replant only the young rhizomes from the edge of the plant cluster.
It is important to ensure that it is constantly moist. If a location turns out to be too dry, a more suitable place should be found, otherwise the lily will grow only sparingly or not at all and will not produce any flowers.
Sufficient humus is essential for the flourishing. Therefore, the plant should receive a sufficient dose of humus or mature compost every spring.
In fall, the Japanese lily can be cut back. After pruning, a perennial that is too large can be divided with a spade. The section is then planted just as deep elsewhere in the soil.
Diseases and pests
If the Japanese iris receives an ideal location and thus sufficient moisture, there are no diseases or pests to fear. Locations that are too dry endanger their existence and let them dry out.
Winter protection is not necessary, but over time a layer of leaves provides important nutrients. In rough locations in particular, it is therefore advisable to protect young plants in particular from severe frost and to apply foliage.
Use in the garden
The Japanese iris enriches every garden pond with its wild perennial character. Beautiful companions at the water’s edge are hollow Joe-Pye weed (Eupatorium fistulosum), marsh-marigold (Caltha palustris) or marsh-meadowsweet (Filipendula ulmaria).
From a distance, rabbit-ear iris looks most beautiful when planted as a group. Keep a distance of at least 35 centimeters (13 in) between the young plants. The perennial rhizomes should be planted in the ground in spring or autumn. Potted plants, however, can be planted the whole season.