The mysteries of the Orient sometimes wend their way into our everyday lives. Such is the case with the culture of Japanese iris.
Here is a plant with striking beauty—a real garden “stopper,” yet so many gardeners have shied away from growing it with the excuses: “too difficult to grow . . . only for certain climates . . . needs special soil . . . it’s a bog plant.”
Myths About Japanese Iris
The Oriental aura surrounding these plants has caused people to make—and believe—these statements.
But these myths have exploded, for Japanese iris are not difficult to grow; they can be grown in most sections of the United States; the “special” soil they need is little different from the “special” soil needed for many of our garden plants; and Japanese iris is not bog plants and can be planted in the perennial border.
History of Japanese Iris
Although many gardeners may think so, Japanese iris is not new in the plant world. Both Japanese and American hybridizers have been working on their development for many years so that today’s varieties have stately blooms 10” inches across on stems to 4’ feet tall.
Their blooming period is a little later than that of tall bearded iris.
Tips on Growing Japanese Iris
But how do you grow them? If you can grow azaleas and rhododendrons, you can grow Japanese iris. Their needs are quite similar, and they share a mutual dislike for lime and alkaline soil.
Prepare the bed for Japanese iris just as you would for any perennial or rose plant—digging soil out about 6” inches deep and mixing in an equal quantity of peat moss (acid kind), rotted manure, or compost.
Japanese iris is planted deeper than tall bearded kinds—with the crowns 2” inches below the surface.
For each plant, mix into the soil a handful of complete fertilizer of a kind sold for acid plants like rhododendrons.
Watering and Soil Requirements
The best time to plant Japanese iris is in the fall. Water them thoroughly at planting time and keep them watered until they are established.
They should also be heavily mulched for the first winter with ground corn cobs or other organic material; avoid wheat or oat straw, as Japanese iris are susceptible to wheat rust.
One of the reasons why Japanese iris have been marked as bog plants is that they need a great deal of water in the spring through blooming time. In Japan, the growers flood the beds, but that is unnecessary.
Ample watering in the spring is sufficient. Once blooming has finished, they need only the natural rainfall, as long as it is somewhere near 30” inches a year. In the dry sections of the country, they may need more than the natural rain.
A note of caution on watering, however. If the water supply is quite alkaline, you may have to maintain the correct soil pH (below pH7) by applying an acidifying agent or acid peat moss.
Fertilization and Suitable Climate For Growing Japanese Iris
Japanese iris are heavy feeders, so they must be fertilized every year. Fall is the best time, and you can use either manure or one of the complete fertilizers made especially for azaleas, rhododendrons, or camellias.
You can grow Japanese iris in almost any section of the country except the very deep South.
All you need to do is pick the right site (they like full sun), maintain a good fertile soil, keep the soil on the acid side, and ensure they get plenty of water in the spring and fertilizer in the fall.
44659 by William Leonard