Story and Photos by Norman Winter
I have heard some suggest that Dutch iris is a short-lived perennial, but those growing at the Coastal Georgia Botanical Gardens, such as the variety ‘Romano’ have been returning since the late 1990s. I’ve led a life comparable to a house flipper, so my knowledge regarding the longevity of perennials comes primarily through word of mouth or reference books, but in Savannah they were stunning every year.
Iris ‘Telstar’ is another that always brings out the cameras. It has been in the ground three years and is naturalizing wonderfully. Most years, the Dutch irises bloom late March through April. But last year’s mild winter had blooms emerging in February.
When I first typed “Dutch iris” into my favorite search engine, it came back asking if I meant “Dutch Irish.” Holy ancestry! When I convinced the search engine that I meant plants, I quickly realized that this is the most famous florist iris for cut flowers.
There is certainly some complexity with this group. Dutch irises are actually a group that originated in Spain, Morocco, Portugal, and other Mediterranean countries with Iris xiphium. The resulting hybrids with I. tingitana, I. latifolia, and I. lusitanica have resulted in garden bulbs that bloom with both beauty and structure.
The Dutch iris is a bulb, not a rhizome. Most references suggest a cold hardiness of Zones 6-9 but it’s not hard to find gardeners touting a return in Zone 5 when a protective layer of mulch has been added. All of Georgia should find a level of success with this iris.
The soil should be fertile and very well drained. It stands to reason if I am raving about their beautiful blooms in March, fall is the best time to plant. It is possible to find container-grown plants in the spring, in which case, take advantage and get them established in your landscape.
Bulbs should be planted 3-5 inches deep. Almost every reference suggests planting them 3-5 inches apart or up to 12 bulbs per square foot. In Savannah, our plants are normally vigorous reaching up 36 inches, so a wider spacing of 8-12 inches makes me a little more comfortable. Massing your planting definitely gives the best show. As with daffodils (Narcissus spp.), leave the foliage on the plant until it dies after the bloom. This ensures sufficient energy for next year’s blooms.
If the dying foliage is problematic for your display, plan for their disguise. For instance, if you looked at the garden’s ‘Telstar’ iris blooming you would also see a blooming Loropetalum, and the blue-fruited Mahonia. What you don’t see are the perennials that will come up screening the old iris foliage.
One of my friends in Mississippi created quite a showy display with the exquisite ‘Wedgewood’ Dutch iris, Louisiana phlox (P. divaricata), and daffodils.
If you’ve never planted Dutch iris, you are missing a real treat. It will be a garden perennial that you will cherish for years to come.
Quick Facts and Keys to Success
Common Name: Dutch iris
Botanical Name: Iris xiphium, I. tingitana, I. latifolia, and I. lusitanica hybrids
Bloom Color: Bicolor blooms in shades of blue, lavender, purple, yellow, white, and pink
Bloom Time: Late February – early April
USDA Hardiness Zone(s): 6-9
Type: Perennial bulb
Size: 24-36 inches
Exposure: Full sun
When to Plant: Spring or fall
How to Plant: Space bulbs or container-grown plants 8-12-inches apart.
Soil: Fertile, organic-rich, well-drained
Maintenance: Leave foliage intact after bloom until it dies.