Reticulata Or Dwarf Bulbous Irises

Like many of their relations, reticulata irises come from Russia and the Middle East where they thrive in cold winters and hot dry summers. Probably there are myriad species still to be "discovered" in remote areas of Iraq, Iran or Afghanistan.

They are plants for full sun at the edge of a path, or in the rock garden where it's easier to prevent them from being swamped by larger, summer-flowering plants. Give them gritty, reasonably rich, very well-drained soil that is neutral to alkaline. If you grow them in pots, make sure they are fed extra-well. A good tonic is a quarter of a bucket of chicken manure topped up with water. Serve the reticulata irises a drink of the liquid every two weeks from mid-fall.

For maximum effect, grow these irises in groups and clumps. However, they do need to be lifted every two or three years as they increase quickly when happy, and overcrowding can make them more susceptible to ink disease, a fungus that is sometimes a problem. If necessary, the disease can be controlled by dipping the bulbs in a fungicide prior to planting.

While they like moisture in early summer when the bulbs are in reproductive mode, they don't like lots of summer rain. If this is typical of your climate, they should be lifted annually, once they are dormant - no later than June. It's important to give them plenty of time to develop their root system during fall, so plant them again in mid- to late summer, about 3 in (8 cm) deep, and add a little slow-release fertilizer. Make sure they are well-watered in winter and spring; in heavy soil provide the bulbs with a layer of sand below and above planting level.

Characteristics

The two long leaves are usually four-sided in cross section, but sometimes cylindrical. The leaves of reticulated irises are either four-ribbed or eight ribbed. These irises die back in the summer after they have completed their blooming and reproductive cycle.

The species Iris reticulata is a native of the Caucasus and a good choice for border edges and rock gardens. The flower may be red-purple or blue-purple and blooms very early, along with the early crocuses. The small flowers actually have no stem but rise on a perianth tube up to 6 inches long formed of the standards and falls. The appearance of the flowers is typically iris like.

Another better-known reticulated iris is I. danfordiae, a distinctive, small, yellow-flowered iris that is native to Turkey. The danfordiae flowers are easily recognized by their very much reduced standards, which appear more like tiny bristles than regular standards.

The reticulata iris I. histrioides is a good garden choice because of its large, pale blue-purple flowers marked by yellow ridges. This plant is very hardy and the bulbs remain of good productive size. Another native of Asia Minor, this iris sends up a sturdy bloom stalk even before the foliage appears. The leaves grow to a mature length of 16 to 20 inches and are wider than those of other bulbous irises.

Culture

Grow these irises in a sandy or gravelly soil. They are good subjects for rock gardening. The reticulated irises will thrive on sites that are open, sunny and well draining.

Plant the small bulbs in the fall along paths or in rock gardens. Plant them in masses or large groupings so that the small flowers can make a statement when seen from afar. Up close, they are exquisite, rivaling orchids in their beauty.

If your spring climate is cold and rough, you may prefer to grow the reticulated irises in pots, where they will flower when provided with cool temperatures. Plant several bulbs to a pot. Use a well-draining gravelly or sandy mix, but do not use pure sand or gravel because it will not retain moisture at all.

The reticulated irises can be shy bloomers and may produce many small non-flowering bulblets after the first season in the ground. Normally, the rule of thumb is to plant bulbs at a depth of about three times their height. If you plant the reticulated iris bulbs deeper than that, about 4 to 5 inches deep, the individual bulbs will be more inclined to remain of blooming size.

Species

I. reticulata

This iris comes from the Caucasus. It is the tallest of the species, with comparatively large flowers sitting about 6-7 in (18-20 cm) above the ground amid the foliage. These flowers are valued for their clear colors -shades of purple striped with gold -and for their perfume, as well as their early spring appearance. And if you can wait three or four years until it flowers, the plant is easy to grow from seed, although it does produce bulblets that mature quickly to flowering stage.
I. reticulata would seem suited for growing in pots or troughs for the flowering to be enjoyed at close quarters. It is easy to move out of view too, when the foliage becomes unsightly. If this works for you, great, but some gardeners find these irises don't thrive in containers. In any case, they should be replanted in the garden after one year in a container and fresh bulbs used in the pots or troughs the following year.

I. histrioides

This iris has lovely formal, almost navy blue flowers, made spectacular by soft dottings of deeper blue around the white haft with its clear yellow median stripe. They appear long before the foliage and subsequent blooms appear lighter in color, almost a Wedgwood blue. So hardy, this iris will pierce blankets of snow to display its dainty flowers.

I. danfordiae

Miniature species. Bright, showy and yellow -if you're lucky enough to entice it to bloom. This iris requires rich, light soil and excellent drainage. This one really requires patience even if it does flower for you, for the parent bulb then proceeds to split into infant bulblets that take another three to four years before flowering.

I. bakeriana

It is very rare iris with slender eight-sided leaves -an unusual but useful identifying feature. Another iris to lift its flower above bare earth, its tiny blooms -2 in high on 4 in perianth tubes (5 cm x 10 cm) -are light blue with distinctive dark purple splashes on the falls. Bulbs are more pointed and slender than other reticulata irises and it likes sandy soil. Growing this one in a container helps you to keep track of the bulbs and their offsets. Sink it in the ground at planting time to do its growing and bring it inside where you can revel in its gorgeous blooms. Flowering time is after I. histrioides and before I. reticulata.

I. winogradowii

This iris comes from the Caucasus where it grows in damp meadows. Not widely grown, its flowers resemble those of I. histrioides but are pale primrose yellow, with darker dotting on the falls. It grows well in semi-shade in peaty, cool soil where summers are dry.
Several cultivars have come onto the market in recent years, all making attractive early spring-flowering garden plants. 'Cantab' is a selected form of I. reticulata with pale blue flowers; 'Katharine Hodgkin' has flowers of sea-green, sulfur yellow and blue; 'Sheila Ann Germany' has silver-gray flowers in early spring and a shape that shows her parentage from I. histrioides, and 'Natascha' is ivory white with green veins and a yellow blotch.