Siberian Iris 'White Swirl'

‘White Swirl’ is a historic Siberian iris introduced by Fred Cassebeer in 1957. Its large, pure-white flowers have broad standards and horizontally flaring falls; the American Iris Society records a height of 38 to 40 inches and late-season bloom ([American Iris Society](https://wiki.irises.org/Sib/SibWhiteSwirl), [Chicago Botanic Garden](https://www.chicagobotanic.org/plant-information/plant-finder/iris-sibirica-white-swirl-siberian-iris)). ## Seasonal Interest The white flowers rise above a clump of narrow, green leaves and bring a bright late-season accent to perennial borders. The cultivar page records its introduction, flower color, form, and awards. Like other Siberian irises, it flowers best where spring growth receives steady moisture. ## Growing Conditions Choose full sun or partial shade and fertile garden soil that stays moist while draining freely. Siberian irises are clump-forming perennials; avoid prolonged drying during active spring growth. Illinois Extension notes that the species group tolerates wet sites, while the RHS recommends moist, well-drained soil for named irises. Local climate and soil affect mature size and flowering dates. ## Maintenance Remove spent stems after bloom and clear declining foliage in autumn. Divide crowded clumps in early autumn or spring, keeping divisions watered while roots establish. See the [RHS iris growing guide](https://www.rhs.org.uk/plants/iris/border/growing-guide) for general care and division guidance.