Iris

Iris is an accepted genus in the Iridaceae family, native across the temperate Northern Hemisphere to the Philippines. Its species vary in their underground structures and growing needs, so a genus-level record does not define one mature size, hardiness range, bloom season, or moisture requirement; [Kew records the accepted genus and native range](https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:326330-2), and the [RHS provides separate guides for wet-soil and bulb irises](https://www.rhs.org.uk/plants/iris/wet-soil/growing-guide). ## Diversity and form Some irises grow from rhizomes, while bulbous irises are also cultivated. The RHS identifies Iris laevigata, I. ensata, and I. pseudacorus among the species suited to moist borders and pond margins; these examples show the range represented by the genus rather than traits shared by every iris. The RHS also describes bulb irises as a distinct group, including plants with different flowering times and forms. ## Growing conditions For bulb irises, the RHS recommends a sunny position and well-drained soil. Moisture-loving Iris species have different needs and may grow at pond margins. Choose light, soil, and water for the species or cultivar when it is known; this genus-level listing cannot provide one care prescription. Existing size, zone, bloom, and water values are retained as catalog values, not asserted as universal genus traits. ## Maintenance For the wet-soil types covered by the [RHS wet-iris guide](https://www.rhs.org.uk/plants/iris/wet-soil/growing-guide), divide congested clumps every three or four years and remove spent flower stems. The [RHS bulb-iris guide](https://www.rhs.org.uk/plants/iris/bulb/growing-guide) discusses a separate group and should be followed for those plants. Match aftercare to the actual iris group instead of applying one schedule across the genus.