Plant Japanese Iris: Attract Attention To Your Garden

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Would you like your garden to attract the attention of all who pass by?

If so, plant Japanese iris, Iris kaempferi. This large, graceful iris comes into bloom in late May, June, or July, depending upon the section of the country, just as the last tall bearded iris have faded and the English iris is in final blossom.

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Japanese iris then holds the breathtaking spotlight for three to six weeks.

Their flowers vary from comparatively small blooms. 4″ to 5″ inches in diameter to giants measuring 1′ foot across when grown under ideal conditions. The average size of most varieties is 7″ to 10″ inches.

Single flowers have three large sepals or falls and three much smaller, usually upright petals or standards.

The 6 Petal Flowers

So-called double Japanese iris differs only in respect to their standards which are almost as large as the falls and lie upon them, giving the appearance of 6-petal flowers. The few true double varieties have pompon-like centers formed by many modified accessory petals.

Except for pure yellow, most of the iris hues are found in Japanese iris. These scents are ironic because a striking feature of most varieties is the bright yellow spear or signal on the haft, the narrow inner portion of each floral segment.

These iris have been bred for at least 500 years, and even vetting a yellow flower is a wish of hybridizers. In addition to uniform colors, many bizarre and fascinating color patterns unknown to other iris are displayed.

Those who delight in the delicate pink, orchid, and lavender tones are perhaps unequaled. The solid colors include rich, velvety purples from amaranth to deepest violet, reds from rosy purple to deepest shades of crimson, and blues from soft azure to dark navy.

To some fanciers, the multicolored varieties are the most intriguing of all. They are usually veined, marbled, picotee, or stippled. Many are exotic and incredibly beautiful. Still, another color pattern is described as varied by the Japanese and striated by American authorities.

Growing Iris In Water

Contrary to some believe that this iris must be grown in or near water, the most prominent American and Japanese growers maintain extensive commercial stocks in dry fields with irrigation only if rainless periods occur before the blooming season.

After flowering, the plants require no more water than other perennials. However, abundant moisture front early spring until the blooms appear is necessary for maximum performance. 

In the Pacific and Atlantic coastal belts, as well as places bordering the Great Lakes, where yearly rainfall is heaviest, vigorous growth and typical flowers can be expected with little or no additional water.

But where humidity is low during spring and summer, constant attention to moisture supply is imperative. Lack of water during the growing period will affect the flower size to a remarkable degree.

A variety growing under ideal conditions may produce 12″ inch flowers on 5′ to 6′ foot stems. The same combination in poor soil or where moisture is lacking may produce 6″ inch flowers on 2′ foot stems.

Does Japanese Iris Grown On Alkaline Soil?

Japanese iris will not thrive in poor or alkaline soils. Lime is fatal. The soil must be neutral to slightly acid, with a pH of 7 to about 6.5. Heavy clay or loam soil well enriched with rotted manure is preferable.

Drainage is not an essential factor as the wild Iris kaempferi grows chiefly in mountain marshes in Japan.

Japanese iris are very hardy and, once established, will endure sub-zero temperatures. Their native range extends from northern Japan, where winters reach 40° degrees Fahrenheit below zero, to southern Japan, with frost-free winters.

Consequently, plant losses are more likely due to a lack of attention to soil or moisture conditions than low temperature.

Propagation may be by plant division or seeds. Japanese iris grows readily from seed and will bloom the year following early spring sowing. Unless controlled pollination seedlings are produced, the sources will be predominantly single-flowered.

Planting Japanese Iris In Spring

Plants may be divided in early spring or anytime after flowering until early fall. Spring planting is recommended in the North, but fall planting is best in warm climates with hot, dry summers.

Plant divisions will not bear flowers of maximum size until the second year, and as long as a plant appears vigorous and blooms satisfactorily, it may remain undisturbed.

Liberal applications of rotted -manure or commercial acid fertilizers in early spring and immediately after flowering will postpone the necessity for dividing and transplanting.

Weak, stunted growth and little or no bloom on old clumps indicate that division is needed. Japanese iris are bothered little by garden pests or plant diseases. Thrips, perhaps the worst enemy, are easily controlled by sprays or dust.

Whether planted in groups or as single specimens in the perennial border or alongside ponds or streams, these magnificent iris satisfy the most discriminating gardener with their impressive flowers and tidy appearance even after the blooms have passed. Unfortunately, Japanese iris names at present are unreliable and muddled.

Japanese Iris Varieties

The following list of varieties, represent a varieties of colors and patterns.

  • WHITE – BETTY F. HOLMES, double; ISO-NO-KAMONE, double Higo; PERFECT PEACE, double; ZAMA-NO-MORI, single.
  • PINK AND ORCHID – LIGHT-IN-THEOPA double; MATA HARI, single; SHIN-RAN, double.
  • LAVENDER – LAVENDER GIANT, single; SHINO-NO-ME, double Higo.
  • RED – KARAHAsHI, double Higo;
  • MA-HOG A N Y, double; RED RIDING HOOD, single.
  • LIGHT BLUE – MARGARET S. HEN. mucKsoN, double; MRS. J. A. HAYDEN, double; NAGAO-ZAN, double Higo.
  • DARK BLUE—HISAKATA, double Higo; KONGOSAN, double.
  • RED STIPPLED – AKA-ECRURIN, single; KURUMA-DONIE. double Higo; MIYUKI-GURMA, double Higo.
  • MARBLED – HATSUKI, single; NISHIKI-GI, double Higo; TORA-ODORI, double.

44659 by Stanley Anderson