Spuria Irises

Originally from the Mediterranean area of Europe, including the Iberian Peninsula, spuria irises are beardless or apogon irises that stand out because of their flowers, which have slim standards and falls in the species, and thus resemble the slim graceful flowers of bulbous irises. Currently, botanists recognize about a dozen species plus a number of subspecies in this class of irises.

History

The irises grouped as spuria irises are native all around the Mediterranean Sea, from Spain around to North Africa. These irises also can be found in lesser numbers as far north as eastern England and Denmark, and as far east as Russia, Afghanistan and even western China.

Spuria irises were first introduced into England by Sir Michael Foster in the late nineteenth century. Best known of his introductions was a hybrid called 'Monspur' that proved valuable to spuria hybridizers.

It wasn't until the 1920s that irisarians began to develop serious programs to improve spuria irises for home gardens. T. A. Washington, the first American breeder of spuria irises, used 'Monspur' as well as other species in his hybridization programs. The majority of Washington's. hybrids inherited the summer-green foliage trait from 'Monspur' and the species Iris halophila.

Iris hybridizers in the United States have been in the forefront of spuria breeding programs and are responsible for many excellent spuria cultivars in a wide variety of colors. While spuria growing and breeding concentrate in California and the Southwest where the climate is sunny and warm, increasingly spuria fanciers and growers are from places like Missouri and Texas and even states like Minnesota and Montana. The spuria "bug" also has bitten iris growers as far a field as Europe, New Zealand and Australia.

Characteristics

Spuria irises will flower one to two weeks after the tall bearded irises. The flowers and stalks are tough and won't break as easily as those of tall bearded irises. Spuria irises are wonderful for floral arrangements, each bloom lasting up to three or four days. Cut the flower stalks when the flower buds just begin to show color.

These are among the tallest of irises, most growing as tall as 3 to 4 feet under good growing conditions, and some reaching a height of 5 feet or more. The flower stalk should have at least two buds in its terminal and each branch. Three to four buds per stalk is common, especially on plants with large flowers. Seven flower buds to a stalk is possible but not common. The branching on the spuria flower stalks is sinuous. Leathery leaves, woody rhizomes and wiry roots are characteristic of spuria irises.

Many spuria cultivars are summer dormant. They will stop growing during hot summer months. While they are summer dormant, they need no water to supplement scarce summer rains. A few spuria irises, including 'Belise', are classed as "summer-green," they do not go dormant in the summer, but stay green and continue to grow. Summer-green spuria irises may need extra water if summer rains do not provide enough moisture.

There is a great deal of variation in the number of chromosomes that spuria species have, so much so that it is interesting that many of them can be hybridized. Chromosome numbers range from diploids (original species with the original chromosome number) with a 2n of 16to a high count of 72. The high chromosome count is found, oddly enough, in a particularly dwarf spuria. There are a number of natural tetraploid spuria irises, those with twice the normal number of chromosomes, a trait that is significant for greater size, vigor and substance.

The trends in spuria iris hybridization are toward shorter plants, flowers with wider petals and flowers without signals, those colored marks that appear in the same locations as the beards of bearded irises.

Spuria irises, though little known to flower arrangers, are wonderful as cut flowers. They also help extend the iris season and make great focal points in the garden. They have been bred in many color variations and patterns, including bicolors, bitones and halos.

Culture

Spuria irises can take more water and fertilizer than tall bearded irises. Growers in the southwestern United States should cut off spuria irises water supply and let them go summer dormant after they flower and summer heat is beginning. In areas farther north and areas with summer rains, spuria irises will stay green and growing all summer long.

The method for planting spuria irises is to mix 2 gallons of compost into a planting hole that is 12 by 12 by 18 inches. Also mix in a handful of slow-release fertilizer and a handful of super phosphate. Plant spuria rhizomes an inch deeper than tall bearded irises in wet but well-draining spots where tall bearded irises will not thrive. Avoid extra watering during periods of heavy rain and high humidity. This will help the spuria irises avoid their main enemy, mustard-seed fungus.

Composted barnyard manures are ideal for fertilizing these heavy feeders. If you have no access to manure, you can use a commercial fertilizer such as 10-10-10 or 10-20-10. Plan to plant them in the fall, like most beardless irises, and apply a heavy winter mulch the first year in areas where there usually are subzero temperatures.

An organic soil that does not completely dry out and a site in the full sun are two keys to growing spuria irises successfully. The richness of the soil will have a considerable effect on the size and bloom production of spuria irises. Keep spuria irises well weeded. The combination of weeds, moisture and high temperatures can encourage one of the few disease problems that spuria irises have-Southern blight, a fungal disease. Since iris borers may be a problem in the Midwest and northern areas, be sure to clean up old foliage and blooms.

Spuria irises can be lifted and divided in either fall or early spring. Do not let the rhizomes dry out during the process. Spuria irises generally are shorter the first year after dividing and replanting-in the case of larger plants, there may be a difference of a foot or more between the height of the first-year transplant and that of successive years. There is evidence that storing spuria rhizomes in the refrigerator before replanting them may trigger faster growth and earlier bloom.

These irises also are easy to grow from seed and set seed easily. Spuria seeds germinate better if planted immediately when the pod starts to split. If the spuria seedlings have good growing conditions and are planted early in the growing season, they may bloom the second year after planting. If you don't plan to collect the seed, be sure to cut spent blooms so the plants will not waste energy producing seed. Unless you take the time to make planned cross-pollinations, the seeds would be the results of open pollination by bees and other insects, and thus probably not valuable for growing.

Species

The blooms of these irises are similar to Dutch and Spanish (or Xiphium) irises - those usually found in florists' shops -and, like the Xiphium irises, they make excellent cut flowers. Frequently, the Spuria iris will open two or more flowers at the same time on long, usually unbranched stems. They flower in early summer, at the same time as the tall bearded irises, and their strong colors stand out among foliage plants. Their flowers have an unusual distinguishing feature, even after being cut: there are three nectar drops at the base of the falls and standards. Most tall modern spuria irises are bred from I. crocea and I. orientalis.

I. orientalis (formerly I. ochroleuca)

This iris is a salt marsh iris in its natural habitat. In cultivation it is one of the best-known Spuria iris. This iris grows to more than 3 ft (1 m), forming handsome clumps, with flower stems up to 4 1/2 ft (1.5 m) in damp conditions. Flowers are large and white, blotched on the falls with bright egg-yolk yellow.

I. crocea

This iris is another of the tall spuria irises, a vigorous sunshiny plant from Kashmir, growing up to 4 1/2 ft (1.5 m). It flowers in early summer and the bright yellow blooms may reach 7 in (18 cm) in diameter. Falls are wavy or crinkly at the edges, standards are long and narrow. This is an easy one to grow in a sunny border in good rich soil.

I. spuria

This iris, which gives its name to the series, is difficult to describe because it is so variable. It ranges in height from 16-28 in ( 40- 70 cm) and the colors of its flowers vary through shades of yellow, blue-mauve and white. They are slender in form, daintily proportioned and bear fine veining on their falls. This iris is a native of Europe, from England through to Sweden, Hungary and the former Czechoslovakia, growing in wet meadows and salt marshes.

I. monnieri

This iris is considered to be an ancient hybrid of I. orientalis and I. xanthospuria. The flowers are slender and aristocratic with tall, very upright creamy standards while the falls are deeper yellow. Records show that it grew at Versailles in 1808 with the name of 'Iris de Rhodes' and was painted by Redoute. Apart from the color of its flowers, it is very similar to I. orientalis.

I. graminea

This iris forms an attractive low clump with plenty of fine, grassy foliage in which the delightfully fruit-scented flowers nestle. This iris will grow in sun or semi-shade, enjoys rich moist soil and looks superb in a container, so long as it is not allowed to dry out. Several plants growing together make an excellent weed-suppressing group, though it is deciduous. The lilac-violet flowers, finely veined on the falls, appear in early summer. Though small, only 3 1/2 in (8 cm) across on stems about 8 in (20 cm) tall, they display the typical spuria form.

I. sintenisii

This iris is another low-growing species, more dwarf and compact than I. graminea and very suitable for a rock garden. Unlike I. graminea, it is evergreen. Its flowers, in late spring or early summer, are blue-purple, on stems up to 12 in (30 cm) tall. Like some of its taller cousins this iris is reluctant to move and it's easy to damage the roots when dividing a clump.
The best time to transplant is in early spring or after rain in early fall. It needs plenty of moisture at its roots, preferring not to be baked dry in summer. In the Balkans and Turkey this iris grows wild in dry scrub and grass.

I. kerneriana

This iris is one of the most attractive of the small spuria irises for the rock garden or front of the border. The height is about 12 in (30 cm). Flowers appear in late spring with slender blooms comprising creamy white standards and falls marked in deep yellow.
The dull green foliage is rather sparse in comparison to I. graminea and the flower stems overtop the foliage by several inches. This iris likes a sunny position in good, well-drained soil but should not be allowed to dry out when dormant in fall.