Irises
What are they?
Irises are typically either herbaceous perennials with spreading root stocks that flower in summer, or arise from bulbs and flower in spring. Most species have sword-like or broadly grass-like leaves and are similar to members of the lily family in many ways.
Where are they found?
Both herbaceous and bulb irises are popular garden plants and may be found as relics or 'escapes' from cultivation in grassy or disturbed places such as roadsides, cemeteries (where they may spread voluntarily from original plantings) and urban environments. Our native species are plants of wet ground, shady places and churchyards.
Identification
The structure of iris flowers readily sets them apart from the flowers of other plant families. The three outer petals (technically called tepals in this group) have narrow bases and broad, flattened distal parts - in horticulture these are called 'falls'. The three inner tepals are smaller and erect (and are often called 'standards'). The species in our area can be identified by studying their flowers and details of the leaf shape. Species with simple or rhizomatous root systems tend to form clumps and have laterally flattened leaves that stand upright like sword blades. Species with a bulbous or tuberous root system more typically have curved and channeled leaves that clasp the stem at the base.
Yellow Iris Iris pseudacorus
Native. Generally found in wetland habitats, especially around ponds and in swamp woodland, but sometimes also found as a garden relic or throw-out in drier places. Flowers late May to July. Can be told from yellow forms of Bearded Iris by the greener (not blue-green) leaves which are not as stiff as those of Bearded Iris.
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Stinking Iris Iris foetidissima
Locally native in shady places and woodland, but also widespread as a garden escape and (especially) in churchyards. Flowers May to June. Flowers an unusual colour and difficult to describe, being pale creamy-yellow to brownish-yellow with veins coloured in varying intensities of purple; the overall effect is a rather 'muddy' flower from a distance. This species suffers greatly from a rust fungus which produces heavy spotting on the leaves.
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Bearded Iris Iris x germanica
Widely grown as a garden plant and occasionally found as a garden throw-out on roadsides and in waste places. Flowers May to June, sometimes later. Flowers of garden cultivars come in an amazing array of colours from white through pink to deep maroon, purple, blue or yellow, while many are bicoloured.
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Siberian Iris Iris sibirica
Occasionally grown as a garden plant and rarely found as a garden throw-out. Flowers May to June. Smaller and more delicate than Bearded Iris and other garden cultivars. Stems hollow, tubular (basal) part of flower relatively short - 4-7mm long - and the flower bract is papery and brown at the time of flowering.
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Hybrid Irises
Occasionally grown as a garden plant and rarely found as a garden throw-out or where deliberately planted around village ponds. Flowers May to June. An assortment of cultivated varieties are grown in cultivation, mostly involving Iris versicolor, I. ensata and I. laevigata, for use in damp soil or around ponds. Hybrids between these species are also produced and many appear to be of unknown parentage and do not key readily to any of the known species. Such plants typically have rather large flowers with broad petals and share the pith-filled stems and partially green flower bracts that help to distinguish them from Siberian Iris.
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Pyrenean Iris Iris latifolia
(English Iris) Native to the Pyrenees. Occasionally grown as a garden plant and once found naturalised at Hingham, Norfolk. Flowers May to June. Flowers a rich, clear blue. Leaves, which are not flattened like those of most other large iris species, die down in winter.
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Dutch Iris Iris x hollandica
Occasionally grown as a garden plant and rarely found as a garden throw-out. Flowers May to June. Large, showy flowers that can be white, yellow or any shade of blue or purple - ir mixes of those colours. More often grown commercially for cut flowers than as a garden plant and doesn't seem to persist long in the wild. Leaves, narrow, arching, folded along their length to give a u-shaped cross-section.
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Reticulate Dwarf Iris Iris reticulata
Commonly grown as a garden plant and popular for planting in cemeteries. Though not officially recorded 'in the wild' in East Anglia, this species is common enough to attract the attention of anyone studying plants in the area. Flowers late February to March. Small plants, to only 30cm or so high, growing from bulbs and often forming discreet clumps.
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