The Other Irises: Japanese and Siberian Irises for Multi-Season Beauty

Most gardens host tall bearded irises, but they’re only a fraction of the iris family. Japanese and Siberian irises offer graceful, grassy foliage and stunning flowers—low-maintenance, disease- and pest-resistant perennials attractive across three seasons.

Japanese iris ‘Beni Tsubaki’ flares horizontally like a dancer’s silk scarves, creating saucer-shaped blooms up to 9 inches across. Prized for over 500 years, they extend the iris season into July. A single stem often bears three or four flowers; established clumps bloom for two weeks or more on sturdy, stake-free stems.

Iris Varieties

Iris Construction

All iris blooms share a basic structure: three upper petals (standards) and three lower sepals (falls). Gentle arcs of blue-green, ribbed Siberian iris leaves create peaceful pondside scenes. Siberian and Japanese irises thrive near water, not in it.

Tycoon

Deep blue-violet ‘Tycoon’ blooms glisten with dew. Siberian irises require less digging, dividing, and replanting than tall beardeds.

Siberians

Stately Siberians bloom late spring to summer on stalks up to 4 feet tall. Massed, they shine in the middle or back of mixed borders.

How to Grow Irises

Forget tall bearded iris culture. They prefer limy, well-drained soil that bakes in summer. Japanese and Siberian irises, native to seasonally marshy meadows, need damp earth.

In fall, plant winter-hardy rhizomes 2 inches deep in moist, rich, acidic soil in the garden or along pond/brook banks. Both bloom best in full sun but appreciate a few hours of shade in hot summers. Keep well-watered during dry spells.

Soak Siberian rhizomes in water a few hours before planting. Site where they can remain undisturbed; they bloom best when well-established (several years). Divide old clumps in early fall after centers bald, about every six years.

Japanese irises demand acidic soil—amend neutral or limy soil with peat moss. Divide crowded clumps in fall every 3–4 years. Avoid wet feet in winter.

Top-dress both types with aged manure or compost in early spring and after blooming. Remove dead foliage in late fall.

Japanese Irises

Exotic flowers exist outside the tropics. ‘Persian Rug’, laced with deep purple veins, illustrates why irises are called “orchids of the North.”

Fresh blooms like ‘Electric Rays’ make excellent cut flowers. Otherwise, remove spent blossoms.

Like all Japanese irises, ‘Juno’ needs peat moss. They’re less tolerant of alkaline soils than Siberians.

Forest-green foliage beautifully showcases iris color and form. Pristine white ‘Geihan’ gleams before a fothergilla shrub.

Japanese iris blossoms display well above 2–3 foot bright green foliage. ‘Pink Frost’ is considered tall with 3-foot leaves.

Velvety, crepe-like petal texture is a hallmark. ‘Sparkling Sapphire’ appreciates protection from harsh wind.

Named for a sheer dressmaker’s cloth, ‘Pink Dimity’ is groomed for fairy gardens—but you don’t need magic to grow these easy-care plants.

Mixing Irises in Your Garden

Gardeners often hide tall bearded irises’ mottled summer foliage. But Japanese and Siberian irises remain attractive spring through fall. Their narrow, vertical clumps have the structural appeal of ornamental grass. Use them as bold exclamation marks in moist, sunny, high-profile spots.

• When mixing colors, place lighter shades in back, darker in front. Use creams or pale blues to blend clashing hues.
• Contrast iris foliage against rounded plants: chrysanthemums, violets, heuchera, hostas, ligularia, marsh marigolds, primroses, trollius.
• Since Japanese irises flower June–July, combine with earlier irises (including tall beardeds) to extend the iris season. Select early-, mid-, and late-season Japanese varieties to stretch bloom over weeks. Pair with other acid- and moisture-loving plants: acorus, astilbes, azaleas, calla lilies, camellias, clethra, hostas, leucothoe, ferns, primroses, rhododendrons, rodgersia.
• Grow Japanese irises to blooming size in pots, then partially submerge at pond edges for show. Plant rhizomes (pot and all) in the garden in fall for winter rest.
• Siberians tolerate less-than-ideal soils better than Japanese irises, growing well in neutral to slightly alkaline soils with average moisture.
• Combine Siberians with late-spring to early-summer bloomers: candytuft, campanula, columbines, creeping phlox, delphinium, dianthus, lupines, Oriental poppies, painted daisies, peonies, Shasta daisies, veronica.