- Name also: Blue Flag Iris, Bearded Iris, Garden Iris
- Family: Iris Family – Iridaceae
- Growing form: Perennial herb. Rootstock thick, creeping.
- Height: 40–90 cm (15–35 in.). Upper part of stem branched, cylindrical, full.
- Flower: Perianth regular (actinomorphic), dark purple–pale blue (sometimes red, yellow or white), 8–15 cm (3.2–6 in.) wide; tepals 6, in 2 separate whorls. Outer tepals 3, curving downwards; inner tepals 3, same length as inner tepals, broadly obovate, erect. Stamens 3. Styles 3, stigmatic lobes large, like tepals, shorter than inner tepals. Inflorescence a 2–4-flowered cyme. Flower fragrant.
- Leaves: Basal leaves stalkless, 30–70 cm (12–30 in.) long, smaller than stem leaves. Blade sword-shaped, with entire margin, parallel-veined, usually slightly greyish green.
- Fruit: Elongated, 3-lobed, 4–5 cm (1.6–2 in.) long capsule. Seed develops rarely.
- Habitat: Yards, gardens, roadsides, shores. Ornamental, sometimes wild.
- Flowering time: June.
Irises are easy to recognise with their sword-like leaves and characteristic flowers. The only iris that is native to Finland is yellow iris (I. pseudacorus), but other irises grow in the country too as leftovers from being cultivated as ornamentals. German iris is, along with its relatives, the most popular perennial in Finland. It isn’t any kind of unambiguous species, rather more of a pot pourri. German iris’s original form was already a hybrid, and it produces seeds only occasionally. Original German iris was cross-bred with its close relatives early in the 20th century, resulting in a huge amount of multicoloured varieties. Different degrees of hybridization have produced almost every shade of colour imaginable, most commonly combinations of violet, white and orange. Irises’ colour range is also reflected in its scientific name: Iris is an ancient Greek word which means ‘rainbow’.
Developing irises often involves paying a price with regards to durability and easy care: the most impressive varieties with their large flowers need a lot of care and attention to keep going from one year to the next. Slightly less demanding, middle-sized and quite small-flowered old varieties are satisfied with significantly less: they don’t need to be divided, re-planted or protected in the winter, and are able to survive a long time on their own. German iris’s thick rootstock thrives even when it is choked by vegetation, and iris’s leaves can keep rising from dense grass for dozens of years after it’s been planted.
Siberian Iris and some escapes
Purple-flowered irises that have strayed into the wild might also be Siberian iris, which grows ferally on the other side of the Baltic in Estonia. This species’ leaves are narrower and its flowers are smaller than German iris’s. Also other iris species may escape from Finnish gardens to the wilds, e.g. purple flag (blue flag iris, Iris versicolor), Dalmatian iris (sweet iris, Iris pallida) and dwarf iris (Iris pumila).