Simple Steps to Blooming Rainbows - How to Plant & Grow Reblooming Bearded Iris
How to Plant & Grow Bearded Iris
Reblooming bearded iris add fuss-free color and fragrance to any sunny garden. Large, complex, billowy blooms unfurl in a rainbow of colors and bi-colors in spring, again in fall, and frequently in between! Bearded iris are also highly resistant to deer and rabbits and equally attractive to butterflies. Quite drought tolerant once established, these iris are a high impact, repeat blooming sensation that are impressively low maintenance. Are you ready to plant reblooming bearded iris? Let's see how to care for bearded iris.
Bearded Iris Care
Reblooming Bearded Iris Planting
- Select high quality rhizomes. The success of your reblooming bearded iris all begins with quality rhizomes. A rhizome is a modified plant stem that grows horizontally, or parallel to the ground. Like a flower bulb, the rhizome produces roots, stems, leaves and blooms, and stores nutrition for the use of the developing plants. The quality of the rhizome is 70% of the quality of the growing, blooming plant, so it is important that you select new rhizomes from a trusted source. The vast majority of bearded iris do not rebloom, so take care to select those that are specifically labeled as rebloomers in your zone.
- Full sun. Your reblooming bearded iris will need t least 6 hours of direct sun each day to grow and bloom their best. In fact, the second leading cause of poor blooming is too much shade.
- Prepare the soil. Good drainage is essential for the health and performance of your bearded iris. Wet soils can cause rot. If your soil is compacted or poorly drains, break it up to a depth of 12 inches, and work in organic amendments like compost or dead leaves. For bearded iris, do not add dried grass clippings to the soil, (too much nitrogen is a risk for bearded iris. You might also consider a raised be for the iris.
- Planting depth is shallow! Both reblooming bearded iris, and their single blooming siblings require a strangely shallow planting that leaves a part of the rhizome exposed above the soil line. Planting the rhizome even 1 inch too deeply is the single leading cause of poor blooming among bearded iris - it's that important. In general, a bearded iris rhizome should be planted with the top half of the rhizome exposed above the soil line. If you get a great deal of rain, plant even more shallowly, with only the bottom quarter of the rhizome buried in soil. In very dry climates, leave just the top quarter of the rhizome exposed above the soil.
- Spread the roots out and down. The roots will anchor the iris plant in place, and take in both water and nutrients to support the plant's development.
- Water well. Not only are bearded iris drought tolerant, they do not like abundant water in the soil. Waterlogged soil is a death sentence for bearded iris. Water in freshly planted bearded iris rhizomes, and allow the soil to become fully dry to the touch before watering again. The timing will vary in your garden, but plan on watering roughly once a week until they become established in your garden. The watering will decrease after that.
Reblooming Bearded Care
Now that you have properly planted your reblooming bearded iris, let's look at how to care for them.
- Fertilizing Reblooming Bearded Iris. Blooming both spring and fall, and often between times is a lot of work! Support your plants with a good, low nitrogen fertilizing plan. An ideal fertilizing plan is to mix a 5-10-5 with a bloom boosting superphosphate in a 50/50 blend, and then apply it in the early spring and again after the spring bloom flush is past. Sprinkle the fertilizer onto the soil around the iris, and scratch it into the surface of the soil taking care not to apply any fertilizer in direct contact with the rhizome. Once your iris are established, apply a foliar feeding to the leaves of the plant in September.
- Leave the leaves intact. Do not cut back, fold over, rubber-band or tie the leaves of your bearded iris at any time, unless it has browned off. Periodically, the plant will stop supporting a leaf as it directs new growth in another direction. Only at that time do you want to remove any leaves. The leaves are essential for transforming sunlight into nutrients for the plant's health and blooming.
- Do not mulch. Do not cover the rhizome with mulch. Reblooming bearded iris are incredibly cold hardy and will not need the insulation. The moisture held in the mulch could become a risk of rot if it is on top of the exposed rhizome. Mulching can be a cause for bearded iris not to bloom.
- Divide every 3-4 years. Your reblooming bearded iris will grow and bloom and form additional plants for your garden. Every 3-4 years, divide your iris rhizomes in the late summer to ensure each has plentiful access to resources. This is a terrific opportunity to expand your bearded iris into new portions of your garden with plants proven to thrive in your conditions! (Stay tuned for step-by-step instructions for dividing bearded iris rhizomes.)
Will you be planting reblooming bearded iris this fall? Please take a moment to leave a comment and let me know! If you have any questions about how to plant or grow them that this post did not answer, just ask. I will be happy to get back to you!
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- Kathleen McCarthy