Bearded Culture

This is Nancy riding the lawn mower in the early spring in Oregon. Our season begins with the Snake Head Iris in about February and the Reticulata shortly after that. Below are our Standard Dwarf Bearded (SDB) iris at peak bloom in the middle of April. We will follow this with the Intermediate and Border (IB and BB) Bearded iris. Then our Tall Bearded (TB) will bloom after that. Our MTB usually bloom about the same time as the Tall Bearded.

Nancy on Tractor

Label Parts of Iris The Parts of the Iris:
1. Standards - the upright part
2. Beards - the fuzzy part
3. Rhizome
4. Falls - the part that falls down
5. Stalk
6. Fan or leaves
7. Roots growing from the rhzome

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

For best results, plant iris rhizomes in July, August or September. This is also the 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.

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 bed.

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 corrections.

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 soil, cover rhizomes until new roots begin to grow. Water well at planting time. IT IS A COMMON MISTAKE TO PLANT IRISES TOO DEEPLY.

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 noticable within 2-3 weeks and begins with a new center leaf in the fan. Depending upon the maturity of the mother rhizome and the geographical location, there may not be bloom the first Spring.
planting 01 planting 02 planting 03
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.
3. Firm the soil around
the roots. Newly planted rhizomes should be
watered thoroughly.


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 rhizomes "toes" face inward towards each other about 8 inches apart as they are planted. plant triangle

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 weekly 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.

Soil type for your area will determine your fertillizer 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.

When irises become crowded, usually every 3 to 4 years, bloom will decline. At that time, old clumps may be thinned by removing several divisions and leaving a portion of the clump in the gorund. A better practice is to remove the entire clump replenish the soil and replant a few large rhizomes.
divide 01 divide 02 divide 03
Figure 1. Digging a three year iris clump. Figure 2. Remove excess
dirt and discard the old
center divisions.
Figure 3. Separation the individual rhizomes for replanting.

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