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London, United Kingdom
This blog will contain pictures and information from my everyday encounters with nature in London and the surrounding areas. I will log details of the origin of each photograph thus recording what there is to be seen and where it was seen. I very much welcome anyone else who can upload photos and information about nature in London and the home counties. I work freelance in the film industry so have plenty of days off. I hope to update Monday to Friday and once on the weekend posting at around 19.30, I don't post on bank holidays

Tuesday, 12 April 2011

Green alkanet (Pentaglottis sempervirens)

Dulwich Rd

This is a really common plant, flowering at this time of year through until early summer. I took this picture in the area outside the front of my flat. It usually wont grow larger than 90cm and it likes damp shady areas near buildings. Anyone who lives in London will have seen this plant, whether they recognize it or not. Until today, I didn’t know what it was but it is really interesting. It was bought here in the middle ages , predominantly to be used as a dye which is a strong red and is extracted from the roots.  Both flower and leaf are edible but always be 100 percent sure of identification before you consume anything. The leaves stay green throughout the year, hence the first part of the plants common name and the second part is related to henna denoting the dying properties.  


  1. Hi Julian

    I'm really enjoying your blogs. As someone who spends some of their time in London, I've seen a fair amount of Green Alkanet this year. You find quite a lot of it alongside regents canal.

    Green Alkanet has traditionally been used as food but other members of this family such as Comfrey, Symphytum officinale, which were also used as food, have been shown to contain pyrrolizidine alkaloids, which damage the liver. As a result of this Comfrey-based products have been removed from the market in the USA and the UK and the German health authorities restrict the sale of herbal medicines containing these alkaloids.

    Just to back up what you say about identification - Green Alkanet is easy to identify in flower but the rough, bristly leaves are similar to Comfrey and as you say, you need to be careful about ID.

    There is also the potential for confusing the rosettes of some Boraginacea with those of Foxglove, Digitalis purpurea, which is poisonous.

    Keep up the good work!

    All the best



  2. Hi Paul,

    Thanks for your comments, very interesting. Someone else was telling me about the ban on Comfrey based products. Am I right in saying you'd have to ingest a really large amount for it to be dangerous? I've also been told that some food from supermarkets that we buy all the time contains pyrrolizidine alkaloids with no health warnings. I'll look into it.

    Get in touch when you're next in London.



  3. Hi Jules

    There's research going back to the 1960s that suggests that you don't need much to cause long term damage. Below is just one research paper:

    Early Effects of Pyrrolizidine Alkaloids on the Fine Structure of Rat Liver Cells.

    All the best


    Paul Kirtley's Blog

  4. Very interesting, many thanks for uploading.