Dutch Iris Planting Guide

Slender, bright and with rich colors and overlays, Dutch irises are delightful jewels in the spring landscape. These are the same irises that are favorites of florists and can sometimes be found in flower shops. Grow your own and you can enjoy super-fresh cut irises from your own garden for less than $ .40 a stem the first year, and free after that!

Choosing a Planting Site

Choose a site with full sun to ¾ day sun. Since Dutch irises actively grow in the spring and slip into dormancy by late May or early June, areas near/under open-branched or limbed up deciduous trees can often work. These areas can be sunny and perfect before the trees are fully leafed out. In warmer areas, a little protection from afternoon sun will extend the blooming window.

Soil Prep for Dutch Irises

Look for a site that drains well. Irises are happy in average garden soil, and as with most bulbs, good drainage is important to avoid bulb rot. If your soil is heavy (clay or compacted) consider digging in generous amounts of soil amendments such as a mix of course sand and compost, leaf mold or well-rotten manure. (Your local cooperative extension office can recommend good mixes that are appropriate for your local soil conditions.) A slow release granular fertilizer (10-10-10) mixed into the planting soil according to package directions can be helpful if you soil is lean. Note: we do not recommend using bone meal as it encourages pets and pests to dig up the bulbs you just planted.

When to Plant Dutch Irises

Plant these bulbs in the mid to late fall, when soil in your area has started to cool. Typically, iris bulbs can be planted right up until the soil freezes in cold regions, although earlier planting provides more time for bulb roots to grow. Note that the roots on winter hardy bulbs continue to grow, albeit more slowly, when soils are quite chilly but not yet frozen.

How to Plant Dutch Iris Bulbs

Dig holes 4-5” deep and add a handful or two of compost to the soil you removed. Plant your irises so the bulb base is about 4” below the soil line. Put the bulb in the hole with the pointed end facing up, fill the hole with soil, pat to eliminate air pockets and water well to settle the soil around the bulb. While there won’t be any visible growth in the fall, the bulb’s roots will be growing and creating a network for absorbing nutrients and moisture.

Dutch iris look best grouped in clusters of about 10 per square foot.

During the Spring Growing Season

Dutch irises need about 1” of water a week from rain, irrigation or a combination of the two.

After spring flowering has finished, snip or snap off the flower heads to prevent the plants from attempting to set seed. You want all available energy to go into strengthening the bulbs for next spring’s show. Don’t remove the leaves; they’re working to produce food for the bulbs. Allow the foliage ripen until it yellows before removing it.

At Season’s End

After flowering, your iris foliage will photosynthesize and create food for next year’s show. Then the bulbs will go dormant and sleep through the summer. They don’t need, or benefit from, any extra moisture during the summer. When fall temperatures cool, the bulbs will develop new roots and then wait for spring rains and warmth to prompt the next cycle of growth and blooms.

Insider Tips

  1. Plant Dutch iris bulbs at a rate of about 10 per square foot. These are slender plants.
  2. If you can plant your iris bulbs in a site that is hot and dry during the summer months, this is ideal and will increase plant longevity.
  3. To reap the maximum amount of spring flowers from your iris patch, consider overplanting with glory of the snow, aka chionodoxa, bulbs. After you’ve placed your iris bulbs and added a thin layer of soil. Then place the chionodoxa bulbs and ad all the soil back into the planting hole. Water. In spring you’ll enjoy a sprinkling of starry chionodoxa blooms and then your irises will flower.
  4. For gardeners in zone 5, mulching with 2 inches of shredded leaves or leaf mold will help your irises overwinter more readily.
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Success Snapshot

Light: Full to partial sun outdoors

Soil: Average soil

Depth: Plant 4” deep

Water: Average moisture

Uses: Garden beds, edgings, cutting gardens

Tip: Plant enough bulbs to ensure plenty of irises for cutting

GUIDE: Dutch Iris Planting Guide

They Start Out Looking Like This: