Iris wattii

Not all types of Iris are easy to grow in our warm temperate climate, and I broke my heart in my early gardening days over some of the exquisite ones that I read about in English gardening books - such as the fruit-scented Iris graminea, blue Iris reticulata, the strange Iris foetidissima with its spectacular red seedpods and any number of other ones whose names now escape me. Most of them hailed from places like Spain and Turkey, with climates very different from ours, and their failure in my Sydney garden now makes eminent sense to me. But there is still something about Iris flowers that I find irresistible and I have sought over the years to find species that will grow well here.

White form of Iris japonica

White form of Iris japonica

Some of the easiest of all to cultivate in Sydney flower in late winter and/or early spring and are known as the crested (or Evansia) types of Iris - so-called because they have a 'crest' or ridge on their three larger outer petals (or 'falls') instead of a 'beard'. The majority of these crested types come from Japan and China, and in general, they grow very well here. Instead of wanting baking sun in summer and cold winters like the Mediterranean types, they are denizens of a semi-shaded woodland setting and are generally not as frost hardy as other Iris species. The most well-known form is Iris japonica, blooming now, with evergreen leaves formed into fans 45 cm in height, which multiply quickly into a thick clump via surface-rooting rhizomes. Pale blue or white ruffled flowers appear on branched spikes to 60 cm tall.

Iris japonica Variegata in bloom

Iris japonica Variegata in bloom

Iris japonica will cope with quite dry, neglected conditions; however, they will do better if they are given some moisture (but not too much, as they may rot if drainage is poor), a yearly feed and a blanket of mulch every so often. They are said to dislike lime. They grow well under trees or shrubs such as Camellia japonica and Rondeletia and they are good companions to some of the smaller shade-loving flowers of late winter and early spring, such as hybrid hellebores, , azaleas, Crassula multicava and bluebells. They look effective grown along the edges of paths in shady parts of the garden. There is a cultivar called 'Variegata' (pictured above), which has boldly white-striped leaves. It doesn't flower freely (the bloom is pale lavender-blue with purple and yellow markings), but the leaves are so useful to lighten up shady areas in the garden. They look great with shade-loving white flowers such as forget-me-nots, Arthropodium and snowflakes.

Iris wattii with Helleborus argutifolius in early spring

Iris wattii with Helleborus argutifolius in early spring

A taller plant is Iris wattii (ht 90 cm tall) with much bigger frilled flowers that are out now, coloured a lovely lavender blue and carried on bamboo-like canes that can be 1-2 m tall. They have the same growth form of leaf fans as Iris japonica, and they make a good evergreen clump. They grow in the same conditions as Iris japonica and would probably grow well in a pot. I am enjoying one clump growing nearby a pale pink miniature Camellia and bright blue-spired Plectranthus barbatus; another clump has companions of the pale green saucer flowers of Helleborus argutifolius and the dainty lime-green bells of Nicotiana langsdorffii.

Iris wattii with cream-flowered Clivia miniata in early spring

Iris wattii with cream-flowered Clivia miniata in early spring

A third clump of Iris wattii in my garden grows near cream-coloured Clivia miniata and shrubby Eranthemum pulchellum, which has flowers of the same soft blue as this Iris at the same time of year, and also enjoys a shaded spot in the garden. This pretty pastel combination pleases me every year! Iris confusa is a similar tall Iris, with masses of near-white flowers; Iris japo-wattii is a cross between Iris confusa and Iris japonica, with flower stems up to 2 m in height and beautiful iced-lilac blooms. I haven't ever seen or grown these ones, however.

White form of Iris tectorum

White form of Iris tectorum

When I first wrote this blog many years ago, I included Iris tectorum (ht 30 cm), as another easy crested Iris for Sydney that could grow in sun or shade. I have since concluded they are better in a colder climate. Likewise, other crested irises such as Iris gracilipes from China and Iris cristata, Iris lacustris and Iris tenuis from North America prefer cooler climates to ours and do not flourish here.

Iris germanica in the farm garden, Southern Tablelands, NSW

Iris germanica in the farm garden, Southern Tablelands, NSW

An Iris quite different to the crested sorts but which does very well in our climate is what is sometimes called the common flag or German iris (Iris germanica). It is likely one of the ancestors of the modern-day bearded irises and generally seen in its purple form, though there is also a white variety. It is often seen growing in abandoned country gardens, but it does equally well in Sydney - better than the Tall Bearded ones, which do all right in our climate but never seem to do as brilliantly as in cooler, inland areas. Iris germanica grows best in a hot, dry spot with excellent drainage. It will spread by its thick rhizomes into a clump, which can be divided every few years.

Blog first published 4 September 2011; updated 10 September 2023.