Growing Tips for Iris Flowers

Iris Flower

The beautiful and very popular Iris flower takes its name from the Greek word for rainbow, based upon its wide array of colors across the numerous species included in the genus.

Irises come in a variety of colors, including purple, white, yellow, blue, black and mixed.

There are also dwarf Irises, along with the taller irises most of us are accustomed to looking at and appreciating.

Without a doubt the most popular iris is the bearded iris, which grows particularly well in northern temperate zones. When people think of Irises, this is the flower that usually comes to mind.

These gorgeous perennials aren't too difficult to grow, and with a few best practices should provide your garden with wonderful color year after year. There are even a few things that can be done to extend the short Iris season.

Beautiful Photo of Iris

Source

Irises and Landscaping

You have to carefully think through your landscaping strategy for irises because they spread fast and will disrupt other nearby flowers if you don't keep an eye on them.

The taller iris varieties always look good when placed in the back of your flower bed and can be used as cuttings when they bloom. That's why you may want to grow some extra ones so you can enjoy color in the garden and your home at the same time.

There are also dwarf irises for the front or middle of the flower bed or for a rock garden if you want to go that route. These are usually under eight inches tall and can be worked into a wider variety of areas than their taller counterparts.

Where to Plant Irises

Irises do best in soil that is slightly acidic, with a pH of about 6.8. The good news is they will still do great in most soils as long as they are planted in a place with good drainage.

They will thrive in raised beds or when planted on a slope. The key in most areas is put them where they'll be exposed to full sun. Some very warm climates may require a little shade, but in general they are a sun-loving flower.

For top performance you can have your soil tested for pH and adjust accordingly, but again, they will still do well in most soils, even clay soils, although you will probably want to mix some organic matter with the soil in that case to get better results.

When to Plant Iris

Because irises need to have their roots established before the end of the growing season, it's best to plant them from July throught September, depending on the zone you live in.

In southern regions with milder winters and scorching summers it would be best to plant them in September or October for best results.

How to Plant Iris

One mistake inexperienced gardeners make when planting Iris is to plant them deeper than they need to be.

What should be done is take the rhizomes and place them in the hole that you dug with the roots spread out and facing downward on top of a little area you mound up in the hole. That's for the purpose of drainage when you water it. You must be careful not to have poor drainage or the rhizome could rot.

From there water it, fill it in, and be sure to keep the tops of the rhizomes above the ground. If you live in a very hot climate or have sandy or light soil, you could in that case cover the rhizome with about an inch of soil if you want.

When each rhizome is placed in the hole on the small mound, pack it in, water it, and then fill in the rest.

While iris can be planted close together, it's better to place them from a foot to a couple of feet apart unless you want to do more work than you may desire to.

If irises are placed too close together you'll have to continuously thin them out, making more work for you.

How to Plant Iris: Step-by-Step Gardening

Iris Care

Watering Iris

When planting new Iris they need to be watered during the first season in order to get their root systems established. It's better to water deep and infrequent than shallow and continually.

Less is more for Irises when it comes to watering, and it's best to underwater than water too much with this flower. There could be more watering requirements in very hot areas, so keep that in mind, especially with new plants.

Once irises are established there is little need to water them ever again, unless a very hot, dry climate requires it.

Fertilizing Iris

Soil types determine how irises will need to be fertilized, but a general rule of thumb is to use a fertilizer with a lower nitrogen, as higher nitrogen levels could encourage them to rot. Something like a 6-10-10 works well.

You could also use superphosphate or bone meal as an alternative, both of which are effective.

Iris doesn't need a lot of help, so if or when you fertilize, apply it lightly to the plant. Early spring and about a month after the Irises bloom are the best time to fertilize. Some gardeners wait until early fall to fertilize the second time.

Iris Maintenance

As for general maintenance of your Irises, keeping a clean bed is a must for best results.

Once the stems flowers bloom on are finished, they should be cut off near to the ground. If there are any bad-looking leaves they should be removed, although all green foliage should be retained.

As the fall deepens and winter approaches, at that time healthy iris leaves can be removed, leaving approximately six inches on the plant.

Iris Pests and Diseases

Overall there are really only two things to be concerned with for Irises, and that is the root borer as far as insects go, and root rot in relationship to disease.

In the case of root rot, the key there is to be sure to plant them in the right place in your garden to prevent it. That means on a raised bed or sloping area; both of which provide good drainage for the Iris.

If there is an unusual amount of rainfall you may have to check them to see if they're rotting underneath the ground. Take a sturdy spoon or similar object and dig around the plant to see how it's doing.

Assuming there is some rot, remove it immediately and throw it away. You can also dig around the roots and keep them exposed to the sun in order to dry them out if they haven't decayed but are soaked.

For root borers, if you find them you can kill them manually if there isn't an infestation.

If there is enough damage on the leaves to warrant concern, you can use an organic solution like 1 part Murphy's Oil Soap to 9 parts water.

An insecticide solution that works well on the borers is Cygon 2-E.

Keeping your garden clean of debris is the best preventative against the borer.

Protecting Iris in the Winter

Other than what was mentioned immediately above, there is nothing more to do with established Iris plants for the winter months.

Now for Iris planted that specific spring, it would be helpful to mulch them in the first winter while removing the material once spring arrives, as mulching Iris can result in the flower rotting.

If you plant your Irises early enough in the first season you may not need to take this precaution if they are established, but it does no harm to do it in order to be sure.

In colder climates you will almost surely want to mulch or cover them in the first winter. After that there is no need.

Dividing Iris

Iris like to spread out, and because of that every three or four years they need to be divided.

If they aren't thinned out, the blooms will not perform as well, and if you've planted other iris varieties or other flower types, they could be crowded out. Crowding also increases the odds of a disease infecting the flowers as well.

All you need to do is dig up the entire Iris clump (it won't hurt it) and remove the new rhizomes and replant them. Some gardeners opt to remove the old divisions near the center of the clump and simply keep the newer rhizomes in the ground.

How To Divide And Re-Plant Irises

Planting Strategy for Longer Iris Blooming Season

People love irises, but many are disappointed because of the relatively short blooming season, usually lasting about two weeks. Some taller Bearded Iris can last a little longer than that; in some cases as long as a month.

Usually that's from planting two Bearded Iris varieties; one that blooms a little earlier and one a little later, extending the blooming season.

Another option for even earlier and longer blooms is to include dwarf Bearded Iris. They will begin to bloom much earlier than their larger counterparts, increasing the blooming season by about a month.

Finally, you could consider what is called a re-blooming Iris. They have the potential to bloom in the summer and the fall.

I say potential because the second blooms aren't nearly as reliable as the first bloom, so it's uncertain how they'll perform. Much of that is dependant upon the zone, climate and type of soil you plant them in.

But these can bloom from a month to about two months after the first bloom, offering a great option if you put them in an optimum place.

Adding this all up together, you could have two to three months of iris blooms, much better than the usual couple of weeks most gardeners get.

As for blooms in the first year after planting and under normal conditions, about 25 to 40 percent of iris won't bloom during that period.

Other factors hindering blooming are crowding, late frosts in the spring, and weather patterns that aren't normal.

Can Iris Grow in Pots?

Yes, Iris can be grown in pots. You can do this with the taller Iris varietie or the dwarfs.

The difference will be the size of the pot you use to plant them in. The dwarf Iris do fine in a six to eight inch pot, while the larger Iris need a twelve inch pot.

Plant them in the same way you would in the ground, leaving the top of the rhizome exposed to the sun. Don't fill the pot all the way to the brim either. Leave about an inch or so clear at the top of the container.

It's essential the pot you use has excellent drainage because of the propensity for the plant to rot if there is too much moisture.

Don't water until the top couple of inches of mix is dry. Remember, it's always better to under water than to over water a plant.

You should keep the pot outside during the winter months, and when first signs of budding appears, bring it inside to enjoy. They love sun so keep them in a window that gets a lot of it.

Irises grown in pots can also be divided after they bloom. So go ahead and divide them and replant them in the ground or grow your Iris container garden by replanting in another pot.

Siberian Iris

There are a couple of differences between the Siberian Iris and other Irises, which aren't as well known as their cousins. They're a gorgeous plant that deserves more attention and space in the garden.

The first major difference between Siberian Iris and others is that Siberian likes water more than regular Irises do.

You can't let the rhizomes of these flowers dry at all, so they must be soaked overnight when you receive them.

A second difference is in how you plant them. They should be planted deeper than other Irises, with the rhizomes covered with up to a couple of inches of soil.

These Irises are also almost completely maintenance free, even more so than their counterparts.

The care of these plants, including growing them in the full sun and where there is good drainage, is the same as the rest of the Iris family. They like more moisture than normal Irises, but not to the point of the ground being soggy.

Iris Flowers

Irises are stunning and beautiful flowers that should be a part of everyone's garden and landscaping design.

If the right varieties are chosen, we can enjoy irises for at least two months and more, ridding ourselves of the idea we're being cheated by such a short blooming season for the flower.

With that in mind, we can have fantastic cut flowers inside our homes for long periods of time, or simply enjoy a potted Iris if we choose to go that route.

Either way, hopefully you won't think of the Iris any longer as a quick tease in the spring, but a flower that can provide a wonderful collage of blooms throughout the spring and summer months.

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Earth Angel profile image

Earth Angel 4 years ago

GREAT Hub MakinBacon! My great bearded irises are in full bloom right now! They are just stunning! Although they don't last when cut and put into a vase, they do last by bringing in the entire pot! The photos I take of them are also stunning ~ helping preserve their longevity in a slightly different way! Thank you so much for sharing! Blessings Always, Earth Angel! P.S. Would love to see a few photos of the Siberian Iris as well!

;-)

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