Great Plains Gardening

By Edith Koeller

July 30, 2004

Here it is, already the end of July and quite a July it has been for us in Kiowa County. You name the weather phenomenon, with the exception of snow and hurricane, and somewhere in the county someone has experienced it. This is the type of weather that tries gardeners’ souls and thoroughly confuses plants and insects. July is supposed to be hot and dry so plants can grow quickly and set on fruit. In my area the temperature is in the 50’s after 2 ½ inches of rain and hail with high winds as I write this column. This is the second time this summer that the garden has taken the brunt of the storm, so to speak, but we will not complain of the much-needed moisture. When it dries out enough to be out again we gardeners will be doing "our thing".

One of those things that is timely right now is the planting of irises. Whether you are transplanting or planting new varieties this is the time of year to be doing that so they will be well established before the growing season ends insuring blooms next spring.

Where to plant? Irises need at least one half day of sun, preferably a full day. But if the area gets very hot during the day, some shade is beneficial. Some of mine are now in the shaded areas where only early morning or evening sun hits them, and they do not bloom as they should. Only if the budding stem gets well established before the trees above them completely leaf out do I have flowers.

Irises need to be thinned or divided before they become overcrowded, generally every 3-4 years. If irises are allowed to become too crowded the bloom will suffer, some varieties may crowd others out and disease problems may be aggravated. Removing the old divisions at the centers of the clumps and leaving new growth in the ground may thin old clumps. Or, you may dig up the entire clump and remove and replant the large new rhizomes. Digging up the entire plant is usually the best way, as any sign of disease in the rhizomes will be discovered and the affected parts discarded.

Iris will thrive in most well drained garden soils. Planting on a slope or in raised beds helps ensure good drainage. The ideal pH is 6.8 (slightly acidic), but irises are tolerant in this regard. To adjust the pH of your soil, lime may be added to acidic soils or sulfur to alkaline soils. It is always best to have your soil analyzed before taking corrective measures.

Iris should be planted so the tops of the rhizomes are exposed and the roots are spread out facing downward in the soil. This can be easily accomplished by digging a hole slightly larger than the root spread, create a mound of soil in the center and placing the rhizome on top of the mound. In very light soils or in extremely hot climates, covering the rhizome with 1 inch of soil may be desirable. Firm the soil around each rhizome and then water to help settle the soil. A common mistake is to plant Iris too deeply.

Newly set plants need moisture to help their root systems become established. Deep watering at long intervals is better than more frequent shallow watering. Once established, irises normally don’t need to be watered except in arid areas. Over watering is a common error.

Iris are generally planted 12 to 24 inches apart. Close planting gives an immediate effect, but closely planted iris will need to be thinned often. Plants spaced further apart will need less frequent thinning.

Specific fertilizer recommendations depend on your soil type, but bone meal, super phosphate and 6-10-10 are all effective. A light application in the early spring and second light application about a month after bloom will reward you with good growth and bloom. Placing a tablespoon of bone meal in the planting hole is a good way to get the iris off to a good start after planting. Avoid using anything high in nitrogen, as nitrogen encourages rot problems.

Keep your iris beds clean and free of weeds and debris, allowing the tops of the rhizomes to bask in the sun. Bloom stems should be cut off close to the ground after blooming. Healthy green leaves should be left undisturbed, but diseased or brown leaves should be removed.

Until next time…