Saturday, February 4, 2017

The Winter Flowering Iris Unguicularis

By Bryce Williamson

Gardeners are always looking for ways to extend bloom season and iris gardeners are no exception. In his recent blog, Hooker Nichols talk about using Louisiana irises to extend the iris season after the tall bearded irises bloom; for those of us that live in a mild climate, there is a little grown iris that can start to flower as early as October and bloom during the winter months—I. unguicularis, sometimes called the Algerian iris. The term Algerian iris is a bit confusing since clones of I. unguicularis are found in the Greek islands, Greece, Syria, Tunisia, and even Turkey.

Lavender Moonbeams (Tasco)--image by Rick Tasco

With plants that grow 12 to 15 inches in height, the flowers can bloom in the foliage. Producing fragrant flowers off and on through winter, the buds are frost resistant though the flowers are not. Unlike most types of irises, I. unguicularis produce flowers over weeks and even months during the winter; however, the plants are loved by snails and slugs, making it necessary to keep the plants free of debris and snails and slugs under good control or they will eat the flowers before you have the chance to enjoy them.

As a plant from dry Mediterranean areas, this iris survive in the summer with only occasional moisture and grows and blooms in poor soil. I. unguicularis is recommended from USDA Zone 7 and higher only. While not widely grown in the United States, the Royal Horticultural Society has named I. unguicularis as one of the top 200 plants in the last 200 years.

Curtis's Botanical Magazine, 1869

Writing in Curtis’s Botanical Magazine in 1869, J. D. H. May noted that information about this iris was “was first published, without a specific name, in 1789, by Poiret, in his Voyage en Barbarie, v. ii. p. 96, and afterwards, first as I. stylosa, by Desfontaines in 1798, and then as I. unguicularis by Poiret, in 1799.” Today I. stylosa is no longer used to describe this fragrant little gem in the winter garden.

There has been some interest in I. unguicularis in what is now known as Silicon Valley for many years; the late Edith Cleaves, of Los Gatos, California, created the varieties 'Edith Cleaves', 'Winter Gay', 'Winter Goldback', 'Winter Memories', 'Winter Mystery', 'Winter Snowflake', and 'Winter Treasure', but they no longer seem to be in commerce. More recently, the noted Central Valley hybridizer, Richard Tasco, best known for creating award winning tall bearded, median, and arilbred irises, has been working with I. unguicularis too. This last year, he raised 600 seedlings.

Image by Rick Tasco

To obtain plants, two sources are available: Superstition Iris Gardens are selling three of the four Tasco varieties this year in 4 inch pots and can be contacted at or search for the Superstition Iris Gardens page on Facebook; Plant Delight Gardens in North Carolina sells them too and they have an on-line catalogue at

1 comment:

  1. Mine are quite old, in a planter of our 80 year old house and are about 4 feet across. However, sections of them that I've planted in several other, sunnier areas of our property have grown MUCH is about 40 inches high and over 80 inches across. This winter it had an enormous number of bloom all winter. Several young starts are already competing for size and had great bloom this winter also. Normal bloom here is from early October until early March. I've sold many of these plants via my Garden Club spring sales. They thrive with essentially no water, even in our hot summers. What's not to love?


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