Horticultural Highlight: Algerian Iris
In this series, the staff of Duke Gardens highlights plants you’ll find within our 55-acre living collection. This week Jason Holmes, curator of the Doris Duke Center Gardens, talks about one of the earliest flowering species of iris.
Botanical name: Iris unguicularis
Common name: Algerian iris
Family name: Iridaceae (Iris Family)
Plant type: Perennial
Native range: Greece, Turkey, and from Western Syria to Algeria and Tunisia
Locations within Duke Gardens: Leubuscher Rock Garden in the Historic Gardens, Woodland Garden in the Doris Duke Center Gardens
USDA Hardiness Zones: 7a-9b
Site requirements: Dappled deciduous shade where it may have full sun in winter.
Interesting notes: Iris unguicularis is an underutilized iris that blooms from mid-winter through early spring. This iris is well suited to woodlands, areas of full winter sun, and around rocks or walls where it’s protected from extreme cold. The foliage grows 8 to 12 inches long and evergreen; however, I have found that it can use a little spring cleaning to remove brown and yellowing foliage. The flowers are lilac purple with white and yellow throats, and they are borne on stalks 6 to 8 inches tall. Flower tone can vary, and we do have a few cultivars in the Duke Gardens collection. Our first specimen of Iris unguicularis came to us in 2007 from former adult education director Alice LeDuc. It’s planted in the Leubuscher Rock Garden. Algerian iris grows best in neutral to slightly alkaline soil, so adding a little lime or mortar rubble is recommended. It is drought tolerant and deer resistant, which is always an added attribute in this area. Moving or dividing is best done during its dormant season in mid-summer to early fall (September is best).
Iris photos by Jason Holmes.