Dactylorhiza purpurella (northern marsh orchid)

Northern marsh orchid occurs throughout the northwestern part of Europe. It is found in southwestern Norway, southern Sweden, Denmark (including the Faroe Islands) and the UK. In the UK it is widespread in northern England, Northern Ireland, Scotland (including the Shetland Islands) and Wales. It is found at up to 600 m above sea level.

Dactylorhiza purpurella (northern marsh orchid) (Image: Matti Niissalo)

Overview: A tuberous perennial reaching up to 45 cm when in bloom, although usually less than 25 cm tall. Tubers (swollen, underground stem sections) are finger-shaped (as in all members of the genus Dactylorhiza).

Stems: Thick and hollow, developing in late March to early April (after a period of dormancy); mainly green but washed purple towards the tip.

Leaves: Mature plants have four to eight green, broadly lance-shaped leaves (sometimes with a purple tinged edge). Unlike several other species of Dactylorhiza, the leaves are generally unspotted. The lower leaves, which are the longest, are up to 16 cm long.

Flowers: The inflorescences (flowering stalks) are compact and crowded. They usually have 10–40 flowers, but can have up to 80.

The distinctive flowers are violet-purple with a paler throat, opening from mid May to late July, and are about 1.5–2.0 cm in diameter. The lip (the lower petal) is complex in shape and marked with deeper purple lines and spots. The lateral sepals are held at a 45° angle. The upper sepal and the petals form a loose hood over the column, which contains the sexual organs. The thick, downwards pointing spur is shorter than the purplish-green ovary.

Northern marsh orchids are commonly pollinated by bees, including bumblebees.

Northern marsh orchid is occasionally cultivated as an ornamental by a few orchid enthusiasts.

The Millennium Seed Bank Partnership aims to save plant life worldwide, focusing on plants under threat and those of most use in the future. Seeds are dried, packaged and stored at a sub-zero temperature in our seed bank vault.

A collection of Dactylorhiza purpurella seeds is held in Kew’s Millennium Seed Bank based at Wakehurst in West Sussex.

See Kew’s Seed Information Database for further information on Dactylorhiza purpurella seeds.

Dactylorhiza purpurella should be grown in moist soil in sunny conditions. It performs best when grown outdoors, but at Kew it is also grown in containers under ambient temperatures for research purposes.

Commercial plants are not always available, but specialist orchid nurseries sometimes grow northern marsh orchid for sale using in-vitro culture.

Dried and alcohol-preserved specimens of Dactylorhiza purpurella are held in Kew’s Herbarium, where they are available to visitors from around the world, by appointment. The details of some of these specimens can be seen online in Kew’s Herbarium Catalogue.

Leaves of Dactylorhiza purpurella (northern marsh orchid) (Image: Rebecca Hilgenhof)

Dactylorhiza species (including marsh and spotted orchids) are the subject of research carried out by scientists in Kew’s Jodrell Laboratory, in particular with regard to population genetics.

Many species of Dactylorhiza are difficult to distinguish from each other, in part due to being highly variable. They are also subject to hybridisation and changes in chromosome numbers. Kew scientists and their partners use genetic data to differentiate between species and find out about their evolution. The results of these studies can be used to aid identification of Dactylorhiza orchids, which is an essential part of conservation projects.

More about Kew’s 'Population Genetics of UK Orchids' project

Search Kew’s science databases for more information on Dactylorhiza purpurella

Kew Diploma student Matti Niissalo's search for lady's slipper, marsh and spotted orchids in Finland

Sainsbury Orchid Conservation Project

Find out more about orchids at Kew