Irises brighten a backyard with their fabulous flowers – but while some bloom in summer, others are late-winter stars
When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works.
Irises are beautiful perennials that, depending on the type, can bloom between late winter and early fall. Narrowing down flowering times is important when choosing specific varieties for your plot – that way, you can plan how to use them (and what to plant alongside them) accordingly.
From miniature bulb-grown plants to tall, stunning specimens that make a statement in summer borders, theres definitely an iris for everyone. Conveniently, the huge range available can be condensed down into more general groups, which gives gardeners a better idea of when to expect their dazzling display.
So, if youre set on growing irises or learning how to grow bearded irises but not sure how to fit them into your planting schemes, this guide will give you a hand.
Irises are one of the most popular flowers for gardens and landscaping. With their beautiful blooms and sword-like foliage, irises provide striking color and texture to flower beds, borders, and containers. But when exactly are irises in season?
The bloom times for irises vary widely depending on the iris type. By selecting the right varieties, you can have irises blooming in your garden from early spring all the way into fall. This guide covers the key bloom seasons for different iris groups so you can plan out when you’ll have these elegant flowers in peak form.
Main Iris Blooming Seasons
Early Spring: Dwarf irises like Iris reticulata bloom as some of the first flowers in late winter and early spring. These miniature bulbs open their colorful cup-shaped blooms on short stems, providing a welcome show when little else is flowering.
Mid Spring: This is peak season for most bearded iris varieties. The classic tall bearded iris (Iris germanica) varieties put on their spectacular show of ruffled blooms in May and early June in most regions. Other bearded iris types like intermediate and dwarf also bloom in mid spring.
Late Spring Siberian irises (Iris sibirica) and Japanese irises (Iris ensata) bloom in late spring to early summer after most bearded irises are finished. Their unique open flowers and grassy foliage add lovely texture to the garden
Early Summer Spuria irises extend the iris season into early summer, blooming into July in some areas. Native irises like Louisiana iris (Iris giganticaerulea) also bloom at this time
Summer: Dutch irises and English irises, types of bulbous irises in the Xiphium group, flower mid summer into early fall. They make great companions to summer perennials.
Fall: Some reblooming bearded iris varieties will flower again in fall if conditions are right. This second bloom often occurs 8-10 weeks after the initial spring bloom time.
Popular Iris Types and Blooming Seasons
Here is a more detailed overview of when popular iris varieties bloom:
Dwarf Iris
- Bloom Time: Early spring
- Details: These tiny bulb irises flower earliest. Iris danfordiae, Iris reticulata, and Iris histrioides bloom February to March in mild winter climates and March to early April in colder areas. Grow these petite irises in rock gardens, borders, and containers.
Bearded Iris (Iris germanica)
- Bloom Time: Mid to late spring
- Details: This classic iris has over 80,000 registered cultivars. Bloom time depends on type and climate. In general, dwarfs bloom first in April, followed by intermediates in early May. Tall beardeds flower mid May into June, with some reblooming again in fall.
Louisiana Iris (Iris giganticaerulea)
- Bloom Time: Late spring to early summer
- Details: Louisiana irises love wet soil and put on a striking display of huge, brightly colored blooms in water gardens or moist garden soil in zones 7-10. Peak bloom is May to June.
Siberian Iris (Iris sibirica)
- Bloom Time: Late spring to early summer
- Details: These dependable perennials bloom late spring into early summer. Cultivars range from tall types over 4 feet to compact dwarfs under 1 foot tall. Siberians do well in wet and average garden soils.
Japanese Iris (Iris ensata)
- Bloom Time: Late spring to early summer
- Details: Huge 6 inch blooms make a dramatic statement in late spring and early summer. Japanese irises need rich, moist soil and are ideal for ponds and water gardens.
Spuria Iris
- Bloom Time: Early to mid summer
- Details: Spurias extend the bearded iris bloom season into summer, blooming into July in some areas. Ruffled blooms rise above arching sword-like foliage. Spurias tolerate wet and dry soils.
Dutch Iris
- Bloom Time: Mid to late summer
- Details: Dutch irises are bulbous irises that flower mid summer into fall. Their strap-like leaves and elegant uniform blooms make them great cut flowers. Plant en masse for a bold summer display.
English Iris
- Bloom Time: Mid summer to early fall
- Details: Much like Dutch iris, these bulbous irises bloom mid summer into fall and work nicely in perennial gardens, borders, and containers. English irises are known for their sweet fragrance.
Extending the Iris Bloom Season
With so many different iris species and cultivars available, it’s possible to have irises in bloom for up to 6 months from early spring through fall:
-
Plant early bloomers like dwarf iris and reticulata iris for the first flush of spring color.
-
Fill the mid spring season with a selection of bearded irises in a range of heights. Go for a mix of early, mid, and late blooming varieties.
-
Add Siberian and Japanese irises for late spring bloom.
-
Include spurias and Louisiana irises for early summer flowers.
-
Extend the bloom season into summer and fall with Dutch and English irises.
-
For fall blooms, choose reblooming bearded iris cultivars.
By incorporating a diverse blend of iris types in the garden, you can build a dynamic display that evolves throughout the seasons. With so many stunning colors and bloom forms to choose from, irises are sure to be stars of the garden from spring to frost.
Frequently Asked Questions
When do dwarf irises bloom?
Dwarf irises like Iris reticulata bloom very early, often the first flowers in late winter or early spring. The petite bulbs bloom ahead of most other flowers, adding welcome color on short stems. Popular dwarf iris varieties like Iris danfordiae and Iris histrioides open blooms from February to April depending on your climate. These miniature irises are perfect for rock gardens, edging beds, and containers.
How long is the bloom period for bearded irises?
Most bearded iris varieties bloom for 2-3 weeks in spring or early summer. However, you can extend the bloom season by choosing a mix of early, mid, and late season cultivars. For example, early blooming dwarf beardeds open flowers in April. Midseason bloomers like most tall bearded irises peak in May. Then late bloomers carry the color into early summer.
What iris blooms in summer?
To extend iris bloom into summer, look for spurias, Japanese, and bulbous iris varieties. Spuria iris blooms from late spring into July with unique ruffled flowers. Japanese iris blooms last from late spring through early summer, thriving in moist soil. Bulbous irises like Dutch and English iris flower midsummer into fall, making great companions to summer perennials.
Do irises bloom more than once?
While most iris species bloom just once, some bearded iris varieties are remontant, meaning they rebloom on the same stems in the same season. Often the rebloom occurs 8-10 weeks after the initial spring bloom time. Choosing reblooming cultivars and caring for the plants properly can result in a second wave of flowers in late summer or fall.
When should iris bulbs be planted?
For spring blooms, iris bulbs like dwarf, reticulata, and Dutch iris should be planted in fall. This gives them time to establish roots before winter dormancy. Bulbs can also be potted up in late winter for a head start on growth. Just wait to transplant bulbs into the garden after the last spring frost date has passed.
With such versatility in bloom times, forms, and colors, irises can be enjoyed nearly year-round in the garden. Paying attention to the key seasons when different iris types flower allows you to orchestrate a continuous sequence of elegant blooms.
When do bearded irises bloom?
John has been a garden journalist for over 50 years and regularly answers readers questions in Amateur Gardening magazine. He has also written four books and has delivered many talks over the years on horticulture.
Bearded irises (Iris germanica) have flamboyant flowers and are grown from rhizomes. They are truly beautiful and easy enough, provided you site them in free-draining soil in full sun, says John.
Expect them to put on their show in your flower beds between mid-spring and summer – check the label for more specific info on each. Some varieties will bloom again in late summer or fall, if the growing conditions are right.
An alkaline soil will help to speed up robust growth, says John, who suggests working garden lime into your soil in early spring if its on the acidic side. They also like a damp spot, or at least soil that doesn’t completely dry out, he adds.
Iris germanica Carnaby( credit: P Tomlins / Alamy Stock Photo)
When do dwarf irises bloom?
Iris reticulata or dwarf irises are much smaller than bearded irises, as their name suggests. They are bulbous plants that like well-drained soil, and are the earliest flowering of the irises, bringing a shot of vibrancy to the late-winter garden.
A popular variety is Harmony which has vivid blue petals with yellow streaks and grows to around 6in tall. They are perfect for early spring containers.
Iris reticulata Harmony( credit: Botany vision / Alamy Stock Photo)