Illustration
Dutch Iris
Iris × hollandica
Dutch Iris blooms from May through June.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Dutch Iris
Plant it in full sun. It prefers moderate water. It is hardy in USDA zones 5–9. Expect it to reach about 24 in tall and 6 in wide at maturity, in roughly 1 year (not yet checked).
What was checked
Mature height and spread, hardiness zones, sun and the trait tags were checked against named botanical sources for this plant. The bloom months and water need on this page were not, and each fact above says which. The planting, spacing and size sections are derived from these checked facts by a fixed rule, not checked separately, and the plant type is the library's own classification.
When to plant Dutch Iris
Dutch Iris is a fall-planted bulb: get it in the ground 6 to 8 weeks before the ground freezes, typically October or November in zone 7, the middle of its hardy zones 5 to 9. It pays you back the following May to June.
Month-by-month timing for your zone is on the planting calendar; if you garden near zone 7, the middle of this plant's hardy range, start with zone 7 in October. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does Dutch Iris get?
24 intall5 ft 7 inan adult6 inwideSee Dutch Iris in a garden plan: the planner shows it in 3D beside everything else you add, growing toward this size over the years.
Where these facts come from
Dutch Iris' height, spread, hardiness zones, sun and trait tags were checked against 10 published sources on July 31, 2026. Each one is linked below with every fact it carried, which can include a fact this page still marks as not yet checked, because a source carrying a value is not the same as the value being held to the standard. Facts not in that list, and the planting, spacing and size sections, are not covered by these sources.
- devroomen.comDe Vroomen Garden Productsheight, hardiness zones, sun and trait tags
- John ScheepersBeauty from Bulbsheight, hardiness zones, sun and trait tags
- NC State ExtensionGardener Plant Toolboxhardiness zones, sun, years to mature size and trait tags
- netherlandbulb.comNetherland Bulb Companyheight, hardiness zones, sun and trait tags
- RHSRoyal Horticultural Societyheight, spread, sun and trait tags
- University of Georgia ExtensionUniversity of Georgia CAES Field Reportheight, hardiness zones, sun and trait tags
- University of Illinois Extensionheight, hardiness zones, sun and trait tags
- vanzyverden.comVan Zyverdenheight, hardiness zones, sun and trait tags
- easytogrowbulbs.comEasy To Grow Bulbshardiness zones, sun and trait tags
- Clemson Home and Garden Information CenterClemson Cooperative Extension Home & Garden Information Centerheight and sun
How the checking works, and what each standard covers, is on the verified plants page.
Good to know about Dutch Iris
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note.
Safety
Toxic to dogs, cats and horses; the rhizome is the most toxic part. Eating it causes drooling, vomiting, diarrhea and lethargy. Sap can irritate skin. per ASPCA and NC State
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Design a garden with this
Drop this plant onto a 3D plan, see how it fills in, and watch your whole garden bloom across the year.