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When to plant iris


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Work out when to plant iris bulbs and you can enjoy these sensational flowers from early spring through to summer. With distinctive, elegant petals and exquisite markings they never cease to impress. 

Choose from early flowering varieties with their dainty flowers and delicate fragrance or opt for one of the many taller European types such as Dutch, English and Spanish that come into their own midsummer. These tend to come in a wider range of colors and have larger long-lasting blooms set against dark green sword-like foliage. 

You can grow irises happily in free draining soil and love to flower in a sunny spot, but some will tolerate part shade too. Long lived and pretty hardy – thriving in USDA hardiness zones 3-9 – they will last for several years with very little care and attention. Not to be confused with rhizome irises, bulbous types need an annual cold dormant period to build up energy stores ready to bloom again the following year. 

When to plant iris bulbs

Depending on whether you want petite early flowerers or larger midsummer blooms, this spring bulb guide is laden with expert tips, will help you know when to plant iris bulbs with confidence.

When to plant spring flowering iris

‘Iris bulbs must be planted in the fall because they require a long period of cold temperatures in order to set their flower buds,’ advises Venelin Dimitrov, Product Manager at Burpee . Plant bulbs in fall as soon as possible after receiving or buying your bulbs.

Dimitrov also says to, ‘Select a site in full sun to light shade with good drainage where water does not stand on the surface after a rain event. Bulbs thrive in well-drained, moist soils. Mulch the soil to protect the bulbs from the heat of strong summer sun.’

Smaller spring flowering iris such as Iris reticulata and Iris danfordiae will fill your yard with color and fragrance during February and March, when very little else is in flower. Stunning planted in clumps and naturalized in grass, under deciduous trees, they can create carpets of blue, white and yellow with very little effort. Their open, graceful blooms – with a trio of upright petals set amongst three drooping ‘falls’ or longer petals – are a highly valuable and popular food source for early emerging pollinators. 

When is the best time to plant summer flowering iris bulbs?

Irises are also amongst the best summer bulbs, too. Again, it's important to plant bulbs in fall well before the first frosts.

‘Dutch irises, like bearded irises, grow from bulbs and require a cold period to bloom,’ says Annette Coppess at Breck’s . ‘Try planting these smaller bulbs in early fall – after the weather cools but before the soil becomes extremely cold. These bulbs will need cooler, but not freezing, temperatures to settle into their new home before winter.’ 

Growing to around 20-23 inches (50-60cm) high, these large showy blooms look fantastic growing outside in borders and pots and make brilliant cut flowers too. With colorful blooms in a huge array of striking and unusual shades – including azure blue, white flushed with lime and blush pink to copper, each flashed with a golden eye – they are surprisingly good natured and demand very little attention.

When to plant iris in pots and planters?

As with all bulbous iris, these are best planted in fall, as they require a cold period to prompt them into growth. If you fancy growing these reliable backyard beauties in pots and planters do bear in mind that some types of iris are more suitable than others. 

Paul Blom from specialists Bloms Bulbs says, ‘The lovely Dwarf Iris are among the earliest of the spring bulbs and provide the richest colors and are particularly suitable for the rock garden or pots and small containers. Whereas the Dutch, English and Herbaceous types feel more at home in the border.’

Thanks to their early flowering period and small bulb size, dwarf iris are ideal candidates for layering with other spring flowering bulbs. Known as a ‘bulb lasagne’ it is a popular and easy way to plant up a single container and ensure a succession of blooms that will last for weeks.

Jill Morgan has spent the last 20 years writing for Interior and Gardening magazines both in print and online. Titles she has been lucky enough to work on include House Beautiful, The English

Home, Ideal Home, Modern Gardens and Gardeningetc.com. Although much of her career has involved commissioning and writing about reader homes and home improvement projects, her

everlasting passion is for gardens and outdoor living, which is what she writes about for Homes & Gardens. 

When To Plant Iris Bulbs – Planting Guide 2023

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Irises are reliable and rugged plants that produce beautiful flowers in a rainbow of colors.

And with many species available, you’ll find a wide range of choices as to which variety to add to your garden.

Those new to gardening will find these perennial plants easy to grow. Like any plant, the key is knowing when to plant iris bulbs.

When to plant iris bulbs? To get the best results, you’d want to plant iris bulbs between late summer and early fall. Doing this will result in spring blooms. Make sure it gets at least half a day of full sun or a full day of sun for more vibrant-colored flowers.

What Is the Best Month To Plant Iris Bulb?

Generally speaking, the best months to plant iris bulbs are from July through September.

If you do it this way, the rhizomes will have the most chance to get in the ground, settle in, and start growing roots.

Depending on the conditions in your area, you might even be able to plant them in October, and they’d still have enough time to grow and bloom by summer.

If given proper care and the right conditions, you can expect them to produce flowers anytime from February to May or June.

The tell-tale sign that it’s time to plant iris bulbs is when nighttime temperatures hit anywhere from 40 F to 50 F and up.

Choosing Iris Bulb Seeds

In case you don’t know, rhizomes are the underground stem from which irises grow.

As mentioned, you will find many options when looking for iris varieties to plant and grow.

The final decision will depend on your preferences and your area’s growing zone classification.

To help with your search, here are the most common ones:

Bearded Iris

Perhaps the most common type, you’ll easily distinguish this variety for its downward-facing petals and its “beard.”

These cultivars can survive in USDA Growing Zones 3 to 10.

Planted in early fall in areas that get full sun, you can expect to grow plants as tall as two to three feet.

Then, there’s the dwarf bearded iris from the same cultivars. This type can only grow up to 15 inches high.

If you want something even shorter, check out miniature dwarfs, which are only eight inches tall.

One thing you might not like about bearded irises is that their foliage will become ugly and ratty when they’re finished blooming.

Dutch Iris

The Dutch hybrid group produces small flowers that are either white, blue, or yellow.

Compared to other types, it doesn’t grow from rhizomes but from bulbs.

It can be as tall as two feet when exposed to full sun and planted in USDA Growing Zones 6 to 9.

Dwarf Crested Iris

No more space for plants that need full sun? Try growing dwarf crested irises instead.

While it can tolerate full sun, it grows best when planted in partial shade.

At just six to nine inches, it attracts bees and hummingbirds when it blooms between March and May.

Originating from the Eastern United States, it grows in growing Zones 3 to 9.

Louisiana Iris

As its name suggests, these are most common in the Gulf Coast area.

They like mild temperatures and slightly sandy, acidic soil and can grow from 12 to 60 inches depending on the hybrid.

Plant them in partial to full sun to grow healthy plants.

These beardless, water-loving hybrids are very hardy varieties and can grow in areas categorized under USDA Growing Zone 4 through 9.

Siberian Iris

Like the Louisiana iris, Siberian irises don’t have “beards.”

They grow best in USDA Growing Zones 3 to 9 and in gardens exposed to partial or full sun.

This variety is easy to grow and maintain and will most likely thrive in regions with temperate climates.

Siberian irises continue to have healthy and elegant-looking foliage throughout the season.

How To Plant Iris Bulb

Whether you’re a beginner or an experienced green thumb, you will find that growing irises is a lot of fun.

Aside from having a sea of iris varieties to choose from, you’ll also like that they are a beginner-friendly perennial plant.

The key to having a lush garden bed of healthy irises starts with knowing how to plant iris bulbs properly.

Here are the steps to planting iris bulbs:

Step 1: Ready the Soil

The first step to growing any plant is knowing the kind of soil where it will thrive at.

As mentioned, irises like neutral to slightly acidic soil.

But aside from that, you have to give each plant good drainage and aeration to prevent the roots from rotting.

Step 2: Plant the Rhizome

To plant rhizomes, make sure that the top is exposed.

The holes where you plant them should only be about four inches deep and around 10 inches in diameter.

You should add a thin layer of dirt on the soil surface only if it gets too hot in your area.

If it doesn’t, adding mulch or covering the rhizome will only encourage rotting.

The rhizomes should be around a foot or two feet apart so that they don’t compete for water, nutrients, and soil.

Step 3: Give Them Water

Once you’ve planted your irises, the next thing to do is to water them.

Newly planted irises need thorough watering.

Give them water generously and then wait a few days before watering again.

How To Water Iris Bulb

Any growing plant needs good-quality water to thrive.

For irises, here’s what you need to do to make sure they’re getting enough hydration:

Step 1: Water As Needed

Usually, the soil around your irises will be dry and ready for watering every seven to 10 days.

Do this either in the morning or at night.

Step 2: Stop Watering When the Weather Cools Down

When it begins raining or snowing, your irises won’t need as much water.

By this time, they would have already been established, so you won’t need to water them until the following summer growing season.

However, if it gets very hot and dry in your area, you may need to continue watering them.

They are drought tolerant for the most part, but irises also need help with hydration in extreme conditions.

How To Grow Iris Bulb

When growing irises, it’s very important that you check each plant regularly to make sure they have the right growing conditions.

Here are tips and tricks that will ensure they grow beautifully:

Tip 1: Keep roots aerated and rhizomes uncovered.

From time to time, check that the rhizomes aren’t covered with organic matter, dirt, or debris.

The soil might also need additional care to ensure it still has good drainage and aeration.

Tip 2: Remove dying foliage.

Browned, dead leaves don’t provide any benefit to your irises, so trim them off when any occurs.

In line with this, cutting the flower stalk before the winter season might also help prevent rotting if ever the flower dies due to extreme cold.

Tip 3: Ready your plants for winter.

If your area gets really cold during winter, you may want to add a thin layer of loose much to protect your irises.

Make sure you don’t add too much, though, as it might cause rot because of trapped moisture.

Tip 4: Use eco-friendly weed killers or herbicides.

As winter ends and spring arrives, remove the mulch you added to protect the soil from extreme cold.

Then, pull out weeds and any grasses from around the base of your irises.

Watch out for slugs and other pests, too.

Tip 5: Give them good fertilizer.

Want to make sure your irises get the nutrients they need?

Try adding in fertilizer, but make sure you pick the right kind and not those high in nitrogen.

Instead, use a general-purpose 5-10-5 or 5-10-10 fertilizer. You can also use bone meal or superphosphate.

Tip 6: Divide your irises so that they don’t compete for nutrients.

Over several growing seasons, you can expect your irises to continue growing and spreading from their roots.

In this case, you will have a full bed of irises in a few years.

Avoid overcrowding by making sure you divide the irises every three to five years.

You’ll know this when the rhizomes start to grow into each other.

How Long Do Iris Bulb Take To Grow?

The answer to this question might not be as straightforward as you’d want it to be.

Spring blooming irises will bloom when the weather turns from cool to warm, but it’s not as easy as that.

Basically, they have to experience up to 15 weeks of 35 F to 45 F temperatures for the bulbs to sprout.

Even if they do meet this requirement, you will also probably have to wait a week or two for them to sprout.

When growing irises, keep in mind that only around 60% to 75% of them will bloom in their first year.

So, don’t beat yourself up if they don’t flower their first year.

Conclusion

New to gardening? Growing iris flowers is a good place to start to develop your green thumb.

Whether you plant bearded irises or those with no “beard,” you’ll find that they aren’t as demanding to care for once they are established.

By then, you will only need to divide them whenever they have become too crowded.

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Irises: how to plant and care for them

Irises are one of the easiest flowers to care for and endure even bad weather. In addition, they are very versatile and can be given for almost any occasion. You can order bouquets with irises and other flowers in Odessa at any time of the day or night. Our managers are always happy to provide you with their advice.

Irises, or bettas, are perennial plants of the Iris family. Mature plants need minimal care. Irises are planted from March to September. If you plant a plant in the spring, then in the summer you can see flowers, but you have to wait a whole year for them.

Iris species

There are more than 800 species of irises in the world. This diversity is explained by the fact that bettas easily interbreed and survive even in the most adverse conditions. Very conditionally, all irises are divided into 3 categories: bearded, beardless and bulbous irises. Bearded - the color can be very different, but most often gray-green or purple with flat leaves. The most common group of irises. They are called bearded because they have a strip of villi on the petal, which are a bit like a beard. Beardless - all petals are absolutely smooth (hence the name). In temperate latitudes, only a few beardless species grow, mostly white and blue. Bulbous - has a bulb, blooms in early spring and has a truly huge number of different species. Easy to grow and propagate, usually blooms in early spring. Many do not consider it a separate species of iris.

Planting irises

Planting these plants is not difficult, but it is best to familiarize yourself with some of the features first. Irises, also known as cockerels, cannot live in one place for decades. Given the peculiarities of our climate, it is better to transplant them after flowering and then every 3-4 years. Otherwise, they will occupy all the free space and stop blooming. It is advisable to plant iris on a hill in soil with good drainage and protect the leaves from the wind. You can add chalk if the soil is sour, and treat the root with fertilizer. Irises love rich soil, and if this is not observed nearby, then you need to start preparing the soil.

Add mule, flour or ash if the soil is acidic, or clay soil otherwise. Treat the soil with a fungicide to get rid of weeds. Before planting, the root must be straightened and in no case should the rhizome be completely buried, so as not to provoke the rotting of the flower.

When to plant irises

Bearded irises, the most common in our latitudes, can be planted during the entire flowering period, from early spring to autumn. Beardless irises do not tolerate overdrying of the roots; it is better to plant them in open ground. Additionally, mulch the plant to retain moisture. Typically, irises, also known as cockerels, are planted in the fall, after the flower's summer hibernation. The main thing is that the temperature should not be too low, not lower than 10 degrees.

Features of planting in the spring

First of all, pay attention to the soil - you need it to warm up enough. In warmer regions of the country, iris can be planted at the end of March, in a more temperate climate, choose mid or late April for planting. It is desirable that the soil is loose and neutral, and the plant is protected from the winds. When fallen leaves begin to dry around, then it's time to plant irises. The plant during this period is in a calm state and is preparing for flowering next year. If you divide the iris and plant it in several holes, you will quickly see new buds and the rooting process. When planted in autumn, irises bloom beautifully in early spring, these plants are included in the list of primroses of Ukraine.

Caring for irises

Caring for bearded and beardless irises is almost identical. Despite the fact that the plant is quite unpretentious, it still needs care. During flowering, irises need watering, however, excess moisture in the soil can kill irises, try to keep a balance. In early spring, loosen the soil by 5-9 cm and try not to use dry dressings, as the rhizome is too close to the soil surface. Weeding the soil must be carried out throughout the entire flowering period.

Watering

Iris is watered in sunny weather, preferably in the evening. In early spring and late summer, reduce watering; in hot and sultry weather, water the plant more abundantly. Pay attention to the air temperature to choose the optimal watering regimen. Irises, or bettas, are drought tolerant, so it is better not to add a little water to them than to provoke rhizome rotting by watering too much. After watering, you can loosen the soil a little, but do not overdo it, only 3-5 centimeters.

Top dressing

For irises, a potassium-phosphorus top dressing is usually used, for example: 10 g of the mixture, 55 g of superphosphate and potassium salt. This is enough to fertilize 1 m² of soil. Before flowering, irises can be fertilized with NPK complex and put a little nutrient mixture under each bush. During budding, fertilizing is practically not required for healthy flowers, and if the iris began to wither, just try to loosen the soil. In summer, healthy plants do not actually need to be fed. Before wintering, you can pour 1 tablespoon of mineral fertilizer under each flower.

Pest control

Irises are among the most pest resistant plants, but even they can be affected, especially the most beautiful and newer varieties. There are many pests such as Maybug larvae, thrips and aphids. For the prevention of irises, it is necessary to fertilize and dig the soil in a timely manner. If an infection occurs in the spring, spray the leaves with an antibiotic solution (tetracycline, neomycin). For leaf rust or vermin, use a garden fungicide. Fight insects with insecticides, and ticks with acaricides. In the summer, use preparations containing copper, fungicides and botrytis from the fungus.

When to plant irises outdoors

Irises are charming plants that are a member of the genus of perennial rhizomatous plants of the Kasatikov family. For their proper cultivation, you should know when to plant a plant, how to prepare a place, how to care for irises and when to transplant. This and much more will be discussed below.

Considering the time and timing of planting, the following points should also be highlighted:

  1. The most suitable time for planting flowers in question is the first half of the day.
  2. Time must be chosen taking into account that so that there is no strong wind or drafts.
  3. If severe early frosts are foreseen in the region , then planting should be carried out early.
  4. Irises do not tolerate cold well immediately after planting. Therefore, warm days should be chosen.

Site selection and soil preparation

When planting iris, attention should be paid to soil preparation. The features of soil preparation include:

  1. The plant in question is not recommended to be planted anywhere in the garden , despite the unpretentiousness of the iris to environmental conditions.
  2. The area to be used for planting should be planned ahead of time, bearing in mind that the flowers in question do not like excessive water.
  3. If the groundwater has a high point then the soil should be drained.
  4. Perennials do not bloom well if they receive little light. Therefore, it is preferable to choose a well-lit place.
  5. It is recommended to raise the flower bed about 15 centimeters.
  6. Fertilizers of mineral and organic type will provide the best conditions for the growth of iris.
  7. Many do not recommend applying manure immediately before planting iris. This is best done a year before planting the iris. For a long time in the ground, useful trace elements will become part of the flower bed.
  8. The very preparation of the land consists in its thorough loosening. It is recommended to make a flower bed with a slight slope towards the south.

As can be seen from the above list, preparing the soil for planting such an unpretentious plant as iris does not cause any particular difficulties. When choosing fertilizers, you should pay attention to those that are recommended for perennials.

Planting irises

After choosing the most suitable time and preparing the soil, you can start planting irises. The features of planting the plant in question include the following:

  1. The flower bud can be formed even in summer. This moment is determined by the fact that before the onset of winter it is already formed and next spring and summer it is ready to give flowers.
  2. When planting iris, it should be taken into account that the plants of this genus, which are most susceptible to cold, cannot tolerate frost at about -10 degrees Celsius. Flower buds may die if exposed to this temperature.
  3. The planting unit of the iris is considered to be a fan, a layer, a shoulder blade. It is an annual link of the rhizome, the length is 3 centimeters, the diameter of the planting unit is 1-2 centimeters.
  4. Leaves are shortened by a third of the length , the roots should be about 10 centimeters long.

The above recommendations refer to landings in spring and summer. At the moment, the kidney has not yet begun to tie, but the rhizome has already produced young links. Young links begin to actively develop only 14 days after planting. At the time of laying the flower bud, the iris is already well rooted.

When planting in autumn, it is recommended to choose buds that are already established, about 6 centimeters long and about 3 centimeters in diameter. Having provided favorable conditions, the flower will quickly take root and begin to bloom the very next year.

The success of the planting to a greater extent depends on the correct location of the rhizome in the ground. You can create a planting hole, taking into account the following recommendations:

  1. 0083 location of the root system in the ground.
  2. The hole should be as long as the root system but at the same level as the soil that has been previously fertilized.
  3. At the bottom of the created hole, a small mound is created , on which the root system is located.
  4. During planting, the seedling is pressed and then covered with a layer of earth.
  5. Iris leaf fan must be vertical.
  6. Spreading earth is slightly compacted at the top.
  7. Iris should be watered immediately after planting.
  8. Repeated watering is carried out after the next 3-5 days.
  9. If planting is carried out on a hot day, seedling should be shaded, as strong heat can impair the growth of iris at the very beginning of planting.

Care after planting

Pay special attention to the plant immediately after planting. At this point, it is most vulnerable to environmental influences. The requirements for the care of iris are somewhat different from those for the care of other perennials.

The main points regarding care after planting the iris include the following:

  1. Periodically loosen the soil and remove weeds that may appear near the iris.
  2. Perennial plant in question may be affected by diseases and pests.
  3. Timely watering should also be carried out in case of severe drought.
  4. Seasonal feeding is carried out in order to to prepare the plant for worse growing conditions.
  5. During the winter it is recommended to cover year-old irises with foliage, and when spring comes, the cover is removed. This is necessary in order to protect the not yet fully established plant from the effects of cold. Old plantings do not need to be covered with foliage for the winter.
  6. The use of fertilizer for top dressing is not always a prerequisite for obtaining the best growing conditions. If the type of soil requires top dressing, then three types of fertilizers are used. As a rule, top dressing is carried out in early spring and during the ripening of buds, as well as a month after the flowering stage has passed.
  7. In dry times it is recommended to water in the evening. Do not allow water to come into contact with flowers and petals. After passing half of the summer, watering should be significantly reduced.
  8. Flower stalks that have completely faded should be cut close to the base almost immediately.

Compliance with the above recommendations allows you to keep the plant in excellent condition.

Particular attention should be paid to the control of diseases and pests, as they can harm the iris to a greater extent. Although the plant has a high resistance to diseases and pests, some exposure can lead to damage to the base of the leaves and the root system. It is recommended to avoid waterlogging the soil, as this will lead to rotting of the root system.

If it was not possible to avoid waterlogging of the soil and rotting of the root system, then you should:

  1. Dig up a bush.
  2. Cut out the rotten parts of the root system.
  3. After removing the affected areas, place the bush in a special solution.
  4. After soaking in a special solution, you can leave the root system for about 12 hours in an open area.

Another threat to the plant can be heterosporosis. A similar disease manifests itself quite often in the second half of summer. It appears as brown spots on the leaves. The disease progresses very quickly. Recommendations for the treatment of the plant can be called cutting off the affected leaves and burning them. In order to help the iris, it must be treated with copper sulfate, which is created when calculating 5 liters per 50 grams of the drug.

Not many pests attack the iris, but the most dangerous is the gladiolus thrips. When exposed to the plant, the leaves become oppressed, after a while the wax coating is lost. You can get rid of the pest in question with a special chemical preparation, which is sold in many garden stores.

Another pest that attacks the iris is the cutworm. They eat away the base of the flower stalks - as a result, the flower stalks turn yellow and the whole plant dies. This phenomenon can be avoided by spraying the plant at the beginning of the growing season with a 10% solution of karbofos. The frequency of spraying is 2 times with a week break.

Slugs can also affect irises. The most effective method to control slugs is to place wet rags and burdock leaves between iris bushes. Slugs use wet rags and burdock leaves as cover. By collecting these leaves and rags, you can destroy the slugs. Another, more effective method of combating the pest in question is the use in the evening, in dry weather, of granular metaldehyde at the rate of approximately 30 grams per 10 square meters of area.

When to repot irises

  • Repotting is recommended every 5 years. Compliance with this recommendation eliminates the possibility of expelling the root system to the outside. If the root system is open, then this can lead to a reduction in the abundant flowering of the plant.
  • The ideal time for transplanting is the end of August and the beginning of September.
  • Transplant only after flowering.
  • In late autumn, this procedure is not recommended , as the plant will not have time to take root.
  • The main requirement is transplantation every 3-4 years. Siberian irises should be transplanted once every 10 years. If this condition is not met, then the plant degenerates and ceases to bloom, after some time, it begins to dry out.

Preparing for wintering

Often no special steps are needed to prepare the plant for wintering. Despite the fact that initially irises were immune to environmental influences, recently irises are considered sissies. Some recommendations allow you to save the plant in the winter.

Growers have learned over the years that low-growing irises tolerate the cold best. An example is iridodictiums, whose height is approximately 15 centimeters. Dwarfs can also withstand exposure to low temperatures.

Wintering depends on proper planting and flower care. The plant should be well prepared for wintering. The basic rules include:

  1. When planting, you should choose a slightly elevated place to exclude the possibility of water accumulation around the roots.
  2. Bulbous irises should be kept as dry as possible after flowering.
  3. Dig up the bulbs only after all the leaves have dried.
  4. Some cover the shrub with dry leaves to protect it from cold temperatures.

Basic errors

There are several reasons why the plant in question does not start flowering. Such errors include:0083

  1. The main mistake is the wrong landing. It is this reason that leads to the main problems with flowering.
  2. The second reason is that the plant becomes cramped. After passing 4-5 years, the bush needs to be replanted.
  3. Iris loves a lot of light. If this is not provided, then the bush will not bloom.
  4. Often the reason is that the soil is not suitable.

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