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Iris × hollandica

Dutch iris

Iridaceae

Garden origin; parent species from the western Mediterranean and North Africa

Attracts Pollinators Deer Resistant Drought Tolerant Container Friendly

SunFull Sun – Part Shade

WaterLow · drought-tolerant

HardinessZones 5–9

Overview

Iris x hollandica is a bulbous perennial reaching 18–24 inches (45–60 cm) tall and 4–6 inches (10–15 cm) wide, grown from a small bulb rather than a rhizome. The Dutch iris group was bred mainly from the Spanish iris Iris xiphium and related species from the western Mediterranean and North Africa. Narrow, channeled gray-green leaves emerge in fall or late winter, followed in spring by slender stems bearing one or two flowers. Each flower 3–4 inches (7.5–10 cm) across has three upright standards and three drooping falls marked with a yellow or orange central blaze, in colors including blue, purple, yellow, white, and bronze. Bloom comes in late spring to early summer, a few weeks after the bearded irises. After flowering the foliage yellows and dies back, and the bulb rests dry through summer. The bulbs are hardy to about USDA zone 5 with mulch and are often grown as cut flowers or lifted and replanted. The bulbs and other parts contain irritant compounds that are toxic to pets if eaten.

Native Range

Iris x hollandica is a hybrid group of garden origin developed by Dutch bulb growers in the early 20th century. Its parent species are native to Spain, Portugal, and North Africa, where they grow on dry, sunny slopes. The hybrids have no wild range and are propagated from bulbs.

Suggested Uses

Grown in spring borders, cutting gardens, and bulb plantings, spaced 3–4 inches (7.5–10 cm) apart in groups. It is a widely used cut flower, holding well in the vase. The slender stems suit narrow beds and containers in full sun.

How to Identify

Slender stems with narrow, channeled gray-green leaves and one or two flowers identify the Dutch iris. Each flower has upright standards and drooping falls bearing a yellow or orange blaze, with no beard. The smooth bulb, narrow leaves, and late-spring bloom separate it from the rhizome-rooted bearded irises.

Appearance

Size & Dimensions

Height1'6" - 2'

Width/Spread4" - 6"

Reaches mature size in approximately 1 years

Colors

Flower Colors

Foliage Colors

Bloom Information

Bloom Period

~2 weeks

Spring Summer

Flowering occurs in late spring to early summer, mainly May to June, a few weeks after the bearded irises. Each stem opens one or two flowers that last about a week. Bees visit the flowers. The bloom does not repeat, and the foliage dies back soon after.

Detailed Descriptions

Flower Description

blue, purple, yellow, white, or bronze

Foliage Description

gray-green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 6-10 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 7.5(Neutral)

357912

Soil Types

loam sand

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Time to Maturity

1 year

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Full sun and well-drained soil at pH 6.0–7.5 suit Iris x hollandica, with bulbs planted 4–5 inches (10–13 cm) deep in fall. The plants need moisture during growth and bloom but a dry rest in summer, so wet summer soil rots the dormant bulbs. They are hardy to about USDA zone 5 with a winter mulch and are grown as annuals or lifted in colder areas. In mild, damp-summer climates bulbs are often treated as one-season plants and replaced. A balanced feeding as growth begins supports flowering. Foliage is left to die back to refill the bulb.

Pruning

Cutting the flower stem for the vase, or removing it after bloom, prevents seed formation. The leaves are left in place until they yellow, since they rebuild the bulb for the next year. No other pruning is needed.

Pruning Schedule

summer