To grow irises is one of the simplest flowers. Rhizomes, which quickly multiply over the years, produce larger and wider stands of these attractive flowers. Overcrowding, poor soil fertility, diseased rhizomes or insects eating the roots are just a few of the possible reasons why your iris plants aren’t flowering as they should. The following issues may be to blame for your irises not blooming. In most cases, iris plants that aren’t flowering are suffering from one of these easily remedied issues.
The iris, named after the Greek goddess of rainbows, is a majestic flower that comes in an array of vibrant hues. It’s hardy, reliable, and simple to grow, despite its divine origins. You’ll learn everything you need to know about caring for irises.
What do you know about iris?
Iris is a genus of about 300 species. The tall bearded irises (Iris germanica), which can grow up to 3 feet tall, are the most common irises.
These six-petaled flowers have three outer “falls” and three inner “standards,” which are referred to as “standards.”
Bearded or crested irises (also known as “beardless”) can be found. ‘Bearded iris’ gets its name from the soft hairs that grow in the center of the flower’s stems. Instead of a mop, the hairs on a crested iris form a ridge.
Early summer is prime time for most iris blooms. Reblooming occurs later in the summer on a few—mostly bearded hybrids.
Irises make beautiful cut flowers. Butterflies and hummingbirds love to perch on them. In the garden, lilies are good companions for iris.
When Irises should be sown
- This time of year is ideal for planting irises because the nights should be between 40 and 50 degrees Fahrenheit or above. As a result, they have plenty of time to establish themselves before the winter sets in. Because they go dormant in early to mid-summer, tall bearded iris are best planted in the fall.
- Plant bare rhizomes or irises that you received earlier in the year in a container as soon as you have the opportunity. It’s better to plant them now than to put them off until a more favorable time comes along.
- Planting Site Selection and Preparation
- Full sun is ideal for iris blooming. Even a half-worth day’s of sun isn’t ideal for them, but they can get away with it. They won’t bloom if they don’t get enough light.
- In order for bearded irises to thrive, they must not be smothered by other plants.
- Fertile, slightly acidic to neutral soil is their preferred habitat. Learn more about organic soil amendments and soil preparation for planting.
- Irises prefer “wet feet, but dry knees,” so good drainage throughout the year is critical. In the winter, they cannot survive in soil that is too wet.
- Stir in 2 to 4 inches of compost after tilling or forking the soil 12 to 15 inches deep.
Iris Planting Instructions
- Rhizomes should be planted with the top exposed for bare-root Iris. Plant the rhizome just below the surface of the soil in areas with hot summers to avoid scorching.
- Separate rhizomes by 1 to 2 feet when planting them singly or in groups of three.
- Using a shovel, excavate a 10-inch-wide and 4-inch-deep hole. Place the rhizome in the middle of the soil ridge, with the roots extending outward on both sides. Leave the rhizome and foliage exposed as you fill the hole with soil and firm it down gently.
- Tip: Irises can be planted too deeply, which is an easy mistake to make. If you live in a hot climate, leave the rhizomes of these plants partially exposed to the elements or lightly covered with soil. They won’t do well if they’re buried too deep.
- To avoid encouraging rot, avoid mulching around the rhizome.
- Drain the excess water.
Irises: How to Grow Them
- In the spring, apply an all-purpose fertilizer to the plants by scratching it into the soil. Rhizome rot can be caused by applying high-nitrogen fertilizers to the surface or by using organic mulch carelessly. As soon as the first wave of blooming is over, reblooming Irises should be fertilized again.
- Make sure you don’t drown your irises by overwatering the soil, as this can cause the roots to rot. Drink plenty of water, especially if the weather is dry, like it is in the summer.
- Keep the rhizomes exposed. Iris rhizomes, unlike bulbs, need a bit of sunlight and fresh air to dry out. Toxins are attracted to soil and other plants, so they’ll rot if left exposed. In the spring, irises may benefit from a light layer of mulch.
- Staking is often necessary for taller irises to prevent them from falling over.
- In the foliage, keep an eye out for iris borers (dark vertical lines that may appear watery show up in the leaves). Tips on avoiding pests can be found in the sections that follow.
- Remove spent blooms on a regular basis; Bearded Irises will flower in a staggered fashion.
- After the flowers have finished blooming, cut the stems at their base, but do not trim the irises’ leaves. The photosynthesis of leaves continues each year, generating energy for the plant’s growth the following year. To prevent rot, remove the brown tips and cut the flowering stalk all the way to the rhizome.
- Make sure to remove any foliage that appears yellowed or spotted after a hard frost in the fall and toss the rest in the trash.
- Remove and destroy iris foliage if it has been severely frost-damaged in order to eliminate borer eggs. Check the dates of the first and last frost in your area.
- Forsythia rhizomes should be protected from the winter cold by a light layer of evergreen boughs placed on top of an inch or two of sand. This layer should be removed in early spring after the ground has thawed and replaced with fresh sand.
- Prepare your iris beds for new growth and avoid Iris borers by clearing out the winter mulch and old foliage in the early spring.
Creating Iris Sections
The rhizomes of irises may lose their vitality and stop blooming if the plants are overcrowded. Divide and replant healthy rhizomes in new soil whenever this occurs (usually every two to five years).
When is the right time to divide? Trim back the foliage to six inches after the flowers have faded.
- Dig up the clump of irises as soon as they bloom (around mid-summer). There are numerous offshoots of the original rhizome (the “mother”) that you planted.
- The mother should be removed with a sharp knife so that the rhizomes can be planted elsewhere.
- Rhizomes should be examined for signs of decay or disease, and any infected parts or entire rhizomes should be removed and thrown away.
- Iris foliage should be reduced to a height of 3 to 5 inches so that the plants can concentrate on growing new roots.
- These fresh rhizomes can be replanted in the same spot, or they can be shared and spread the irises’ joy around!
Pests/Diseases
- Irises are drought- and deer-resistant plants.
- Despite this, they are vulnerable to the Iris Borer, an arachnid that lives in the spent leaves of irises. Look for these pests if you see vertical streaks in the leaves! Dig up the rhizome and remove any decayed portions if you notice them.
- Whiteflies, thrips, slugs and snails, aphids, and nematodes may also be a problem.
Species to Consider
- Colorful tall bearded iris varieties liven up the June garden with their vibrant hues. They bloom in June and are typically only planted in the fall.
- After blooming in June, the tall bearded Reblooming Iris ‘Immortality’ offers a second crop of white flowers toward the end of the season. Zone 4 hardiness is required.
- Hardy at least to Zone 4, other rebloomers include “Feed Back,” which has dark purple flowers; “Earl of Essex,” which has purple flowers; and “I Do,” which has white flowers.
- In zones 5 and above, ‘Jennifer Rebecca,’ a mauve pink beauty, is a must-try.
- Irises from the Siberian region, It’s also possible to find I. sibirica in a variety of hues. The delicate beauty of these irises contrasts with the stately beared irises, but they are just as tough.
- The Iris of Japan, Large, flat flowers resembling tropical birds can be found on I. ensata, which grows best around ponds.
Wisdom and Humor
- The iris is both a representation of France’s royal standard fleur-de-lis and the city of Florence, Italy’s official emblem.
- When teething babies were encouraged to chew on a “finger” of dried Iris ‘Florentia’ root for its natural fluoride, it was thought to cure blood and lung diseases.
