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The parasitic purple toothwort, Lathraea clandestina, is flowering now.

Richard Wilford & Katie Price
29 March 2011

The purple flowers of the parasitic Lathraea clandestina, known as purple toothwort, mysteriously sprout from the ground in the Woodland Garden.

The Woodland Garden at Kew, around the Temple of Aeolus, is beginning to reach its spring best, with a range of bulbs and other woodland perennials flowering in the spring sunshine. One of the more unusual looking plants is a parasite known as purple toothwort, Lathraea clandestina. This species is totally dependent on the food produced by other plants to survive so it is called an 'obligate parasite'. It has parasitised the largest tree in the Woodland Garden, the black walnut, Juglans nigra, and the flowers sprout from the ground around the base of this mighty tree.

 

Purple toothwort (Lathraea clandestina) at the base of the black walnut

 

Lathraea clandestina is not native to the British Isles but was introduced in the second half of the nineteenth century and first came to Kew Gardens in 1888.  It grows wild in Belgium, France, Spain and Italy but has become naturalised in Britain and even New Zealand. There is a British native species, L. squamaria, the common toothwort, but it is not as colourful as this species.

 

 

The flowers of purple toothwort (Lathraea clandestina) can appear some distance from the host tree

 

The easiest way to introduce L. clandestina to your garden is from seed scattered around or mixed in the soil, near a suitable host plant. It normally parasitises poplars and willows but has also been found on a number of other trees and shrubs including maples, yew, rhododendrons and alder. In early spring the flowers appear out of the ground. They are pinkish purple hoods that form dense clumps, sometimes a fair distance from the base of the tree on which they are living.

 

Flowers of purple toothwort (Lathraea clandestina)

 

Being a parasite, purple toothwort doesn't have any green leaves for photosynthesis, and after setting seed it disappears from view. It connects to the root system of its host, often deep down in the soil. Like many parasitic plants, feeding off another plant doesn't seem to have a detrimental effect on the host, and this strange species makes a fascinating addition to the woodland garden flora.

 

- Richard & Katie -

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Comments

26 April 2014
Comment: 
Found this plant growing wild in the Foret de Sivens in the Tarn department in France. Thank you so much for solving the problem
13 April 2014
Comment: 
Found several clumps of this unusual plant today in mixed woodlands at Lyons Copse in Hampshire. In over 50 years of enjoying wild plants and being able to identify most, I had never encountered such a strange collection of flowers.......thanks for solving the naming problem.
26 February 2014
Comment: 
A thrilling discovery in a woodland bog in mid west France. Purple clumps,islands of unexpected colour took me by surprise I have been interested in plants all my life but have never seen this beautifull and interesting species in the wild or anywhere for that matter. Thank you to RHS Wisley and Kew Gardens for your assistance in identifying Lathraea clandestina A thrilling discovery in a woodland bog in mid west France. Purple clumps,islands of unexpected colour took me by surprise I have been interested in plants all my life but have never seen this beautifull and interesting species in the wild or anywhere for that matter. Thank you to RHS Wisley and Kew Gardens for your assistance in identifying Lathraea clandestina A thrilling discovery in a woodland bog in mid west France. Purple clumps,islands of unexpected colour took me by surprise I have been interested in plants all my life but have never seen this beautifull and interesting species in the wild or anywhere for that matter. Thank you to RHS Wisley and Kew Gardens for your assistance in identifying Lathraea clandestina A thrilling discovery in a woodland bog in mid west France. Purple clumps,islands of unexpected colour took me by surprise I have been interested in plants all my life but have never seen this beautifull and interesting species in the wild or anywhere for that matter. Thank you to RHS Wisley and Kew Gardens for your assistance in identifying Lathraea clandestina
Abuse Reported. Comment will be reviewed and removed if necessary.
16 May 2011
Comment: 
I spent ages googling images to find the mysterious purple flower we saw in the woods near Hospice de France (we live near the pyrenees) So excited to see and identify it on your web site
3 April 2011
Comment: 
Why can I find no mention of the beautiful perfume from this plant? We found it growing a couple of weeks ago in Devon in the Tamar valley.
29 March 2011
Comment: 
This type of parasatism is fascinating and its depiction appreciated. Perhaps, in a subsequent species article, the molecular biology of which portions of the host metabolism are utilized in order for propagation to occur can be described?

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