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BEARDED IRIS CULTURE TIPS

Remember:  These cultural tips are suggestions, and may need to be modified for your specific growing area.

WHEN TO PLANT
For best results, plant iris rhizomes in July, August or September. This is also the best time to divide and restart clumps of iris that have become overcrowded, usually after 3 - 4 years.

The roots of newly planted irises must be well established before the end of the growing season. In areas with mild winters and hot summers, irises may be planted in September or October.  In areas with a strong winter climate, plant at least 4-6 weeks before the expected hard freeze or killing frost.  

WHERE TO PLANT
Irises require at least a half-day (6-8 hours) of direct sunlight. Some afternoon shade is beneficial in extremely hot climates, but in general irises do best in full sun. Iris will grow in deep shade, but may not flower.  Provide your irises with GOOD DRAINAGE.  Good air circulation is essential.  Water should not stand in the beds.

SOIL PREPARATION
Irises will thrive in most well drained soils. If your soil is heavy, humus - compost - or other organic material - may be added to improve drainage. Gypsum is an excellent soil conditioner that can improve most clay soils. The ideal pH for irises is 6.8 (slightly acidic) but irises are quite tolerant of less-than-perfect soils. Lime may be added to acidic soils and sulfur may be added to alkaline soils.  Have your soil tested before making any correction. 

DEPTH OF PLANTING
Plant your rhizomes at or just barely below the surface of the ground.  Irises should be planted so the tops of the rhizomes are visible.  In extremely hot climates or with very light soils, cover rhizomes with one inch of soil. Spread roots beneath and tamp soil firmly to anchor the rhizomes until new roots begin to grow.  Water well at planting time. IT IS A COMMON MISTAKE TO PLANT IRISES TOO DEEPLY.

BASIC PLANTING STEPS:
Step (1)  Build up a small mound of soil in the center of the planting hole.
Step (2)  Center the rhizome on the soil mound and spread out the roots on either side.
Step (3)  Firm the soil around the roots.  Newly planted rhizomes should be watered thoroughly.  
Be Patient -- Irises are perennials and require time to grow.  New growth may be noticeable within 2-3 weeks and begins with a new center leaf in the fan.  Depending upon the maturity of the rhizome and the geographical location, there may not be blooms the first Spring.

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Figure 1.  Build up a small mound of soil in the center of the planting hole.
 Figure 2.  Center the rhizome on the soil mound and spread out the roots on either side.
 Figure 3.  Firm the soil around the roots.  Newly planted rhizomes should be watered thoroughly.
SPACING PLANTS
Planting rhizomes 12 to 24 inches apart is the norm. Close planting results in immediate effect, faster clump formation, and more color but makes dividing clumps a necessity in 2 to 3 years.  

The photo to the right shows iris being planted in groups of three.  Notice that each of the rhizome "toes" face inward towards each other about 8 inches apart as they are planted.

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WATERING
Newly planted rhizomes need moisture so their root systems develop. Once established, irises usually do not need watering except in arid regions. OVER WATERING OF IRISES IS A COMMON MISTAKE.  After planting, water well and continue watering until the first good rain.  If lack of rain persists, watering should be deep enough to penetrate the shallow root system.  Deep watering on occasion is better than frequent shallow watering. 

FERTILIZATION
Soil type for your area will determine your fertilizer needs. Superphosphate, bone meal or a well-balanced fertilizer with an N-P-K ratio of  6-10-10 or 5-10-5 are recommended. Avoid anything high in nitrogen as it encourages soft growth that is susceptible to disease. A light application in early spring and again a month after bloom is appreciated. Place fertilizer around rhizomes, not directly on them.  Do NOT use Feed and Weed preparations.

DIVIDING CLUMPS
When irises become crowded, usually every 3 to 4 years, bloom will decline. At this time, old clumps may be thinned by removing several divisions and leaving a portion of the clump in the ground. A better practice is to remove the entire clump, replenish the soil and replant a few large rhizomes.

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Figure 1.  Digging a three year iris clump. Figure 2.  Remove excess dirt and discard the old center divisions. Figure 3.  Separate the individual rhizomes for replanting.

GENERAL GARDEN CARE
It is extremely important to keep your iris beds free of weeds and fallen leaves so the rhizomes may bask in the sun. Spacing plants so there is good air circulation will help prevent diseases. Break out bloomstalks as soon as bloom season is over. This prevents contamination of your named varieties by chance bee crosses. These crosses would cause seedpods to form that might go unnoticed. If given time to ripen, they might drop seeds to the ground. The resulting new plants are often unattractive. So breaking out bloomstalks right away is a good garden practice.

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