Iris Care Must-Knows
Bearded and bulb-type irises need well-drained soil to thrive because they will rot easily in soggy conditions. Many of these species are native to rocky mountainsides where there is sharp drainage. If you are looking for a species to grow in moist soil, look for a Louisiana iris, Japanese iris, or a yellow flag iris. Because different irises need such different growing conditions, make sure to do a little research before planting so you can provide your particular iris with what it needs. When it comes to sunlight, all irises need six to eight hours of full sun for the best blossoms and foliage growth. In too much shade, growth may be more stretched and prone to flopping over, and the plants will be less likely to bloom. Bearded irises and other rhizomatous types will eventually need to be divided every two to five years. If it has been quite some time since their last division and your irises seem to be flowering less and less, chances are it’s time for them to be divided. The best time to divide and replant most irises is late summer to early fall. At this point in their life cycle, irises are somewhat dormant and are resting up for their fall growth cycle to begin. To divide your irises, carefully lift the plants out of the ground (a pitchfork works great for this), and carefully tease apart the individual rhizomes. Don’t worry if you break a few roots or rhizomes, as they are pretty tough plants. If there is some fairly large foliage attached to the rhizome, you can cut it back by half (this helps the plant lose less water while recovering from all the dividing upheaval). Once they are all separated, you can replant by digging a small trench and setting each rhizome on a small mound of soil, then fanning out the roots around it. Then, backfill with soil around the rhizome, making sure to tamp down any air pockets and bringing the soil level just to the top of the rhizome. Water your plants well. Give them a good drink once or twice a week for the first several weeks after planting until the new roots begin to grow. Irises are fairly pest-free, but iris borers are their one nemesis. This bug does most of its damage around blossom time, often between mid-April and mid-June. They chew their way into the leaves and then burrow down into the rhizome, leaving behind a trail of frass, a powdery brown residue. Once at their destination, the borers can eat several rhizomes and make their way through an entire bed. Their damage also opens plants up to infection from bacterial rot, too. These insects are tricky to control as they are often hidden within the plant where pesticide sprays can’t reach them. If you do find a damaged plant, dig it up and see if you can locate the culprits and dispose of them. The best method of control is often prevention, so make sure to clean up any debris around your irises in fall and early spring, which is where borers overwinter.
More Varieties of Iris
‘Bennerup Blue’ Siberian Iris
Iris sibirica ‘Bennerup Blue’ produces cobalt-blue flowers with small white blotches. It grows 2 feet tall. Zones 3-9.
‘Electric Rays’ Iris
Iris ensata ‘Electric Rays’ is a Japanese iris with large double violet flowers streaked with white. This award-winning variety grows 3 feet tall. Zones 5-9.
‘Caesar’s Brother’ Siberian iris
This variety of Iris sibirica is a classic Siberian iris with stunning deep purple blooms. Zones 3-8
‘Champagne Elegance’ Iris
This Iris selection has glamorous fragrant flowers, several per stem, that have pale buff-apricot falls with amber beards and white standards faintly blushed pink. This tall bearded type may rebloom in late summer. It grows 3 feet tall. Zones 4-9.
Iris chrysographes
Iris chrysographes is known for its especially dark purple-red fragrant flowers. It blooms in early summer and grows 2 feet tall. Zones 7-9.
Forrest’s Iris
Iris forrestii, a striking yellow Siberian iris, grows about 16 inches tall and has mildly fragrant flowers. It blooms best when given some afternoon shade. Zones 4-9.
Crested Iris
Iris cristata is a wild form native to areas of North America. It bears blue, white, or purple flowers in spring over tiny clumps of sword-shape foliage and grows to 1 foot tall. Zones 3-9.
‘Satozakura’ Japanese Iris
This Iris ensata variety prefers to grow in water or damp places where soil is acidic. Its large, somewhat flat mauve to rosy-pink flowers are yellow at the throat and conspicuously veined. Clumps grow to 3 feet tall. Zones 6-9.
‘Immortality’ Iris
This selection of Iris is a tall bearded type that offers pure-white flowers. It commonly reblooms in fall and grows 3 feet tall. Zones 4-9.
‘Harpswell Snowburst’ Siberian Iris
This Iris sibirica cultivar offers blue-violet flowers edged in white. It grows 3 feet tall. Zones 3-9.
Iris danfordiae
Iris danfordiae is an early-blooming bulb with single yellow flowers in late winter. It grows 6 inches tall. Zones 5-8.
‘Variegata’ Iris
Iris pallida ‘Variegata’ A lovely variegated bearded iris with rich purple blooms and a pleasant fragrance. Zones 4-7.
Louisiana Iris
Iris fulva has 4-inch-wide coppery-red flowers that are yellow at the center but without beards. The swordlike leaves may reach 4 feet tall. Zones 4-9.
‘White Swirl’ Siberian Iris
This variety of Iris sibirica makes tough clumps of narrow green sword-shaped leaves. In midsummer, each stem blooms with several 1- to 2-inch pure-white flowers touched with yellow at the base. Zones 3-9.
‘Yellow Flag’ Iris
Iris pseudacorus ‘Yellow Flag’ grows vigorously in wet places. Its thick clumps of grayish spearlike leaves may reach 4 feet tall. In late spring and summer, 2-inch yellow flowers appear on strong stems. It may become invasive. Zones 5-8.
Iris Companion Plants
Thrift
If you have a hot, dry spot with excellent drainage, you must give thrift a try. A small, tidy plant, it covers itself with adorable bobbing pink flowers. It’s a charming groundcover, edging plant, or rock garden feature. When planted in large groups, it forms a mat of attractive grassy foliage and colorful marble-size balls of flowers. Also called sea pink, this tough plant tolerates wind, sea spray, and is drought-tolerant. They do need well-drained soil to prevent root rot.
Primrose
Take a walk down the primrose path and you’ll never look back! Primroses are a classic cottage flower and are popular with collectors. They covet the hundreds of different primroses available, especially some of the tiny rare alpine types. Many are staples of cottage gardens and rock gardens, while others provide spring color to damp places, rain gardens, and bog gardens. Their basal rosettes of oval leaves are often puckered or are very smooth. The colorful flowers may be borne singly or rise in tiered clusters, or even spikes. Provide humus-high soil that retains moisture and some shade for best results.
Peony
Perhaps the best-loved perennials, herbaceous peonies belong in almost every garden. Their sumptuous flowers—single, semidouble, anemone centered or Japanese, and fully double—in glorious shades of pinks and reds as well as white and yellow announce that spring has truly arrived. The handsome fingered foliage is usually dark green and remains good-looking all season long. Provide deep rich soil with plenty of humus to avoid dryness, and don’t plant the crowns more than 2 inches beneath the surface. But these are hardly fussy plants. Where well suited to the climate, they can thrive on zero care.
Lupine
Lupine draws the eye skyward with its gorgeously colored and interestingly structured flower spikes. Bicolor Russell hybrids are the most popular type. Their large pea-like flowers come in amazing colors and combinations, clustered in long spikes on sturdy stems. Lupine prefers light, well-drained soil that is slightly acidic, and it does not tolerate heat or humidity well. It performs best in areas with cool summers, especially the Pacific Northwest.
title: “Iris” ShowToc: true date: “2022-11-27” author: “Teresa Steinke”
‘George’ iris
Iris reticulata ‘George’ offers velvety dark purple flowers in late winter or early spring. It grows 8 inches tall. Zones 3-9
‘Harmony’ iris
Iris reticulata ‘Harmony’ is a vigorous selection with rich blue flowers in late winter or early spring. It grows 8 inches tall. Zones 3-9
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