Form: Perennial
Hardiness Zone: 4-9
Flower Color: Lavender, white, yellow, pink
Foliage type: Flat, linear, vein-less, upright, grass-like in appearance
Bloom time: June
Height: 27 inches
Spread: 24 inches
Light requirements: Full sun
Plant depth: 1 inch of soil over rhizome
See "Growing Tips" for more detailed instructions
Growing Tips and Instructions
Visit our How-To Cultivation Library to learn more about iris and how to grow them.
Newly received Japanese iris bare roots should be soaked in cool water for a few hours or overnight. Plant individual rhizomes 2-3 inches deep, 6 to 8 inches apart. Give a good 18 to 24 inch spacing between different rhizomes. Water in well to start the root development, do not let new transplant dry out. New transplants may not bloom the first year. Expect your best bloom on 2 and 3 year old plants.
Japanese irises prefer a rich, loose soil with ample organic matter. An addition of well aged manure and compost will help in water retention as well as adding nutrients. The soil pH should be slightly acid, ideally between 5.5 to 6.5. Do not use bone meal or lime, as this will raise the soil pH too much and can kill Japanese irises. Also, do not fertilize newly planted or transplanted Japanese iris as this can burn the roots.
Japanese irises do not like to dry out. Constant moisture will reward you with healthy plants and larger blooms. Wet in the spring and keep moist all summer. They do very well near water, as this is where they naturally grow, or where the water table is high. The crown of the plant needs to be above the water line.
These plants like full sun, with a minimum of 6 hours to bloom properly. In hot climate, some afternoon shade will benefit the bloom.