How To Plant Iris And Do It Right - Flower Patch Farmhouse

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Do you ever wonder if you’re planting your iris bulbs the right way? When I first started growing bearded iris, I quickly learned that how you plant them makes all the difference between a few struggling leaves and a gorgeous flush of blooms year after year.

Now, technically, bearded iris aren’t really “bulbs” at all—they’re rhizomes. But since so many people call them bulbs, I’ll use both terms here. What matters most is getting them into the ground correctly so they stay healthy, multiply, and give you flowers for years to come.

Every spring, my garden is filled with the tall, ruffled blooms of Iris germanica, and they’re always a showstopper. After sharing so many of my iris photos, I realized it was time to walk you through exactly how I plant my bearded iris—step by step—so you can enjoy them in your own garden too, especially if you’re planting them for the very first time.

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So here’s how I do it, in my sun-drenched beds and cozy borders.

What you will Learn about Planting Bearded Iris Bulbs

• Best time to plant Iris
• Where to plant Iris rhizomes
• How to Prepare your Soil before planting
• How to plant Iris for best performance and what to avoid
• How far apart to plant the rhizomes
• Replanting Iris after Dividing
• Where I buy the best Iris

There is a video of how I plant bearded iris at the end of this post.

Bearded Iris are winter hardy in zones 3-9, so most everyone can grow them with success!

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When is the Best Time to Plant Iris Rhizomes

Iris are usually shipped from growers in August and September in the U.S. and that is for a very good reason. The best time to plant iris rhizomes is late summer through early fall.

This is why most bearded Iris growers ship out their selections at this time.

This gives most gardeners the chance to get them in the ground so the rhizomes can settle in and the root system develops before the first hard frost or a hard freeze.

This is also the time that you would dig up and divide the Iris currently growing in your garden.

what you need to know

Dividing Iris

If you plant your Iris correctly then in a few years you will need to divide them. Don’t worry, it’s easy enough and keeps your Iris happy and healthy!

divide your Iris with ease!

After you have either dug up and divided your Iris rhizomes or you have just received some from an iris farm you need to plant them correctly.

This way you will enjoy strong, healthy growing plants with numerous blooms the following spring and early summer.

Where do Irises Grow Best

The best place for irises is in full sun, with at least 6 to 8 hours of sunlight per day. They can tolerate less than half a day’s worth but it’s not ideal, and they won’t bloom well if you don’t give them enough light.

Most recommend planting your Iris bulbs in a dedicated bed or area but I love to plant them in my flower beds and borders with other plants.

Note: You can plant them with other plants that like more water by planting them on a small hill of well-drained soil so they are elevated above the surrounding ground level. They can drain off easily while the other plants get all that water.

This is my favorite tool for digging and planting Iris.

Here is a list of my favorite plants as companions to my Iris.

Prepare the Soil

Clear away any weeds or debris, then loosen up the soil in the sunny spot where you plan to plant your new iris rhizomes.

The most important factor here is good drainage. Irises like their soil moist, but they absolutely don’t want to sit in soggy ground.

Bearded iris generally prefer neutral to slightly acidic soil, though in my experience, they can handle a bit of alkalinity without complaint.

If you’re working with heavy clay, you’ll definitely want to amend it to improve drainage—but honestly, that’s true for most plants.

Avoid Fertilizing Iris when Planting

Here is where I differ from others. I advise you to avoid fertilizer when planting Iris.

The rhizome should have plenty of stored energy so adding fertilizer is not necessary and especially if the soil is well amended each year with compost.

Yet some folks prefer to add fertilizer when they plant. If so then stir the fertilizer into the soil, mixing it in lightly. Don’t just place it in the hole.

Rainfall or watering will deliver the fertilizer where it needs to go if it is stirred into the soil.

If you must use a fertilizer I recommend this one

NOTE: If you struggle with varmints digging up things in your garden then skip adding any bulb fertilizer. Again, avoid adding bulb fertilizer when planting Iris rhizomes.

Why do I avoid fertilizing my bulbs? Many times, bulb fertilizers contain bone meal and that attracts unwanted critters to dig. Or your dog, and bone meal is toxic to dogs!

Remember, unless your soil is very depleted, you do not need to add it at planting time.

The best time to fertilize iris is right after they finish blooming, when the plants are replenishing their rhizomes for the next growing season.

How to Plant Iris Rhizomes

Plant your Iris rhizomes in the soil, making sure to keep them close to the surface.

Note: I have been battling gophers this year. They have been eating my plants including the Iris rhizomes, to deter them from eating my newly planted Iris I put some of this under and around the rhizome.

The Second Thing to Avoid

A common mistake is to bury the iris rhizomes too deep. Iris likes to be close to the soil surface. Leave the top of the rhizome showing, that way I know they are not too deep.

In cooler regions, Iris love the sun on their backs (the top part of the rhizome). If you live in an area with very hot summers, you can cover the backs of the rhizomes lightly with an inch of soil or less.

With the added protection, Iris thrives in extremely hot climates. I grew them in the San Joaquin valley with great success. The climate there is very Mediterranean with hot summer temps.

In cold, cold climates do mulch a bit before hard cold starts but you need to be sure and rake it back as soon as warmer weather begins.

Planting too deeply is the number 1 reason Iris will not bloom.

How Far Apart Do You Plant Tall Bearded Irises?

A good rule of thumb for planting Iris in groups is 6 to 12 inches apart. Good air circulation helps deter fungal disease.

Because Iris thrives here, I leave at least 12 inches so the new Iris can grow and increase. Increasing means making new rhizomes or bulbs you can divide out later for more Iris.

By spacing them a bit further apart there won’t be a need to divide sooner than in 3 years.

Replanting Iris after dividing

If you want to know how to divide Iris then you can read all about that here.

When replanting a particular Iris that I have divided, I like to plant three rhizomes together. That gives me a spectacular mass of blooms in Spring.

Plant them with the pointy noses of the rhizomes facing each other in a circle. Spacing is not critical, but I like to place mine about 6 to 12 inches apart for the reasons stated above.

I firm them in with my foot, you can see my footprints in this photo.

Planting them this close together means you will get a good show of blooms next Spring but you will also need to divide them sooner than if you planted them further apart.

Above the soil is moist but if you are doing this during a drier part of the year water them in and keep the soil moist through the summer but not soggy.

If you are planting a newly acquired rhizome you will most likely only have one, and that is fine. Plant it the same way.

In a few years, you will have enough to divide and replant.

Next Spring you will have some lovely Iris to enjoy.

If it is early Spring and you didn’t get to divide your Iris in Fall you can still do it, read about how here.

Most reputable Iris farms and gardens send out good-sized, high-quality bearded iris rhizomes that will bloom the first year. If you visit an Iris farm, many have new plants in pots too.

When dividing your Iris, you may have some smaller-sized ones attached to the larger rhizomes.

The smaller ones will take another season to grow in size before blooming. So don’t get discouraged if yours doesn’t bloom in the first season.

One pest that can damage Iris is the Iris Borer, read here for more about that. Iris borer can lead to bacterial soft rot.

I hope this helps all those out there who were skittish about growing Iris. Growing Iris is truly very simple and so rewarding.

Watch this fantastic video tour of my Iris in their full glory!

Where to buy Iris Bulbs Rhizomes

My favorite Iris Sources are:Schreiners Iris GardensSuttons Iris Garden

Hortons Iris Garden

Happy Iris Planting!

More to come on Siberian irises, Japanese irises, and other iris varieties you can grow.

On another note: I also teach painting and have a lesson on how to Paint Iris. Hop on over and learn how you can paint Iris one easy stroke at a time!

• Hi, I’m Pamela

  With 45 years of hands-on gardening experience, I love sharing practical tips, proven techniques, and inspiration drawn from my own gardens. My goal is to nurture your confidence, spark your passion, and help make every step of your gardening journey more enjoyable.

  Pamela Groppe a Garden Friend!

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