Iris Plants: Perennial Stalwarts

Siberian irises

Iris Plants Can Be A Colorful Centerpiece Of The Season


The iris not only ranges in color, it has a variety of heights and types that brighten the garden. While sold with bulbs, these mostly grow from structures more accurately called rhizomes.

This post is an overview of different types from the small stature of bulb grown Iris Reticulata to the visual centerpieces of German bearded types, to the large, elegant Japanese types.

There are many types of iris plants and I’ve grown a number of them. Their eye-catching beauty is entrancing, with large graceful blooms floating like large butterflies in many tints, shades and variations. They are colorful, graceful, and sometimes fragrant. Depending on the species they can bloom throughout the season, so let’s look which can be grown in the climate zone 5 of the USA.

Find the type of iris you wish to know about, from small bulbs of the Reticulatas to the large rhizomes of German Iris.

Iris Plant: Reticulata

Plant Description

iris reticulata

One of my favorites, Iris reticulata, is an early bloomer.

One of my favorites, this is the earliest iris bloomer in spring (March – April) for me, and very hardy. Shades of deep blue to purple with interesting golden accent markings on the falls.

Good plant for rock garden, and the flowers are sweetly fragrant. Named for the fact that their bulbs have a netted look to them (reticulata means a fish net, netted, or a network in Latin)

How to Grow

Requires a sunny situation that drains well; Soil needs to stay relatively dry in summer during a dormant period.

Dutch and Spanish iris, Iris Xiphium

Plant Description

beardless iris Bloom late spring (April-May), bulbs sold in the fall, graceful and slender blooms and foliage. Clear, beautiful colors blooming with the lily-flowered tulips.

My favorites were Wedgwood blue with ‘Elegant Lady’ tulips.

The whites, such as ‘White Pearl’, are ethereal. They are often used as cut flowers for arrangements.

How to Grow

Semi-hardy, they prefer sun or afternoon shade and rich, well-drained soil.
Plant bulbs in fall, 4 to 6 inches deep. The top of the bulb should be just beneath the surface of the soil. Feed with low-nitrogen fertilizer.


“German” Iris germanica

Better known as “Bearded Iris”

Plant Description

Bloom in May, these Iris range in height from 2 to 4 feet. They are all colors of the rainbow (hence the name “Iris”, and have many variations of form in both bloom and height.

Intermediate (height 16 to 27 inches), Miniature Tall (height 16 to 25 inches, small flowers), Border (height 16 to 27 inches), and Tall (height 28 to 38 inches) bearded types alternate bloom sequence through the blooming season (shortest blooming first through to tallest blooming latest).

There are also dwarf irises, Miniature Dwarf (height 8 inch or less,) and Standard Dwarf (height 8 to 15 inches). Certain varieties can re-bloom.

How to Grow

The top half of the iris rhizome should be left exposed so that it will not rot, but roots attached to the rhizome need to be covered with soil and require a sunny location for best growth.

Light, loamy soil with a pH of 6 to 7 (prefer slightly alkaline soil) that has been amended with organic matter is best, but just remember that it is mainly too much moisture that is the enemy, so make sure it is well-drained.

Divide every 3 to 5 years. They can be prone to disease and borers, but good cultural practice reduces problems. Planting and dividing information.

Bearded German Iris


Learn more on the Journal: German Iris

All About Irises!


A Must-have Book for Iris-lovers


Siberian, Beardless

Siberian Iris

Plant Description

Siberian iris bloom in June, and these perennials are long lived -for generations. They take a year or two to get settled before they bloom well for you, but then they make up for it!

Mainly purples, blues, and whites, the colors range from nearly black and wine reds to purples, lavenders and blues, to pinks, whites and yellows.

These are my very favorite iris, and one of my favorite garden plants, they are graceful and elegant in flower and foliage. A joy in the garden. Hardy, elegant Siberian Iris are usually easy to grow, without the lifting and dividing shores of the bearded types.

How to Grow

They can be planted in spring or fall, the top of the rhizome 1 to 2 inches below the surface. (This is deeper than most other irises).

They like a slightly acid, moist soil, but do not like standing water. Growing best in moist, well-drained, fertile soils, they tolerate less welcoming situations including clay.

Part sun to sunny. When making divisions for replanting, be sure that each division has about a half dozen or more fans of foliage.

I find they need to be given adequate sun, and kept free from crowding by surrounding plants. The newer varieties, such as “Butter and Sugar” are not as strong or tolerant of neglect as the older ones like “Caesar’s Brother”.

Plant profile on the Journal, Elegant Siberian Iris,

Iris – Black Gamecock

Louisiana Iris

The Gamecock iris is a named variety of the Louisiana iris. Growing in boggy areas and in full sun, this velvet black flower is very showy. Native to U.S. wetlands.


Japanese (Iris ensata), beardless

Iris ensata

Plant Description

Bloom in July, with full fancy flowers in delicious shades of color. Large flowers look like they float above the lance leaves.

How to Grow

They require more water and a definitely acid soil, same conditions as ferns, astilbes or impatiens. They like a rich soil and should be transplanted in fall or early spring; thoroughly soak and keep well-watered while getting settled. Planted 2 to 3 inches deep, they need good winter protection in the north and benefit from mulching (2 – 3 inches). Divide every three to four years.


Inspired Japanese Art

Kaku Jaku Ro Book of a Blue Iris



Plant Description

Bloom in July; ideal for plantings around pools, ponds and low spots. With yellow flowers, it grows 4 to 5 feet tall. Best for a natural, wild site, not so satisfying for cultivated gardens.

How to Grow

It tolerates well-drained areas, but is happiest in 3 to 6 inches of water or areas that stand in water periodically.

General Information

Iris Facts



  • First two, I.reticulata and I. Xiphium, are drought tolerant; the I.ensata. I. siberica, and Iris ‘Black Gamecock’ need lots of moisture.
  • One feeding in spring is important for Irises.
  • In garden design they make a good vertical accent.
  • Falls are three segments of petal-like sepals that droop down on irises. The upper set of petals, three upright segments, are called “standards.”
  • Thrips on the flowers? Control by using insecticidal soaps and hanging blue sticky traps next to the iris beds.
  • Bearded iris especially like heavy feeding of low-nitrogen fertilizer, but all types appreciate some extras of compost and soil kept fertile.

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