The Japanese Water Iris (Iris ensata) is also known as the Japanese Iris, and less frequently as the Oriental Iris or Hanashobu.
One of the many reasons that gardeners enjoy growing this Iris is for its stunning, intricate blossoms. These can be used to add a touch of elegance to aquatic settings.
Photograph of Japanese Water Iris 'Lake Effect' Cultivar by F. D. Richards
The resilient nature of these Irises make them ideal for water features and ponds. They can help to enhance biodiversity, and provide a visually captivating focal point.
These hardy perennials bloom in the summer. Japanese Water Irises have sword shaped leaves and bloom with blue, white or purple flowers. These sit atop of 28 to 36 inch (70 to 90 cm) stems.
Photograph of Iris ensata by TANAKA Juuyoh (田中十洋)
This plant used to be classified by the scientifically as Iris kaempferi, a synonym that is still sometimes used by gardeners.
Japanese Water Iris can be started outdoors from seed in flats. Sow at a depth of 6 mm (1/4 inch) in the autumn or winter.
Locate the flat in a shady part of the garden.
Leave the flat exposed to the elements for a month or so in a shady part of the garden (the seeds require frost stratification)
Once stratified, bring the flats indoors until the spring. Move the flats outdoors again, and once seedlings appear, provide with a feed.
You can transplant the young plants to their final location in early autumn. Use a spacing of about 25 cm (10 inches).
Plants will grow well in both sunny locations and in areas of the garden that have partial shade.
These Irises like to grow in a soil that is rich, has a slightly acidic to neutral pH (5.5 to 7), and is damp.
The germination of Japanese Water Iris can take anything from one month to one and a half years, so patience is required to grow from seed.
If you require further plants, and don't have seed, then you will probably need to hand pollinate the flowers. Once seed as set, sow as described above.
Alternatively you may wish to propagate by dividing the tubers once flowering has completed in late summer, or early in the autumn.
Propagation through of division is a lot less hassle. Simply dig up the clump, give the soil a rinse. Then separate the rhizomes by hand (you may need to use a sharp gardening knife for this step). Each division you make should have at a strong fan of leaves and strong roots. Trim the leaves to about a third of their size. Plant the division into its new location, with the rhizome fractionally below the soil surface. Make sure the new plant is kept moist.
It is necessary to feed then with liquid manure. Divide every four years to maintain strong plants.
If growing as a water garden feature, then grow at the margins where the water is not as deep. Despite being associated with water, they will thrive in a soil with good drainage.
Iris ensata can make a great plant for using in gardens and for landscaping. It has stunning, intricate blossoms, and can be used for aquatic landscape settings.
Japanese Water Iris is not particularly known for its fragrance.
Use a garden location that is exposed to full to partial sunlight. Ideally grow it at the margins of water features and ponds.
Iris ensata is not generally thought to be an invasive plant the USA.
To remove Japanese Water Iris from you garden. First dig around the plant and lift the rhizomes out of the ground. You will need to make sure that you remove as much root material as possible to prevent re-growth. Keep and eye on the area and remove any regrowth.
Iris ensata, the Japanese Water Iris, is a perennial plant valued for its delightful blossoms. This Iris plant is native to Japan, and thrives at the edges of water features and ponds. Grow in areas exposed to full to partial sun. For optimal growth, ensure soil remains moist.
I hope that you enjoyed this guide on how to grow Japanese Water Iris plants. You may also enjoy my gardening guides on how to grow Fothergilla gardenii, Lima Bean plant, and Echinacea purpurea plants.