Wednesday Weed – Green Alkanet Revisited

Dear Readers, I hear so many people complaining about green alkanet, the way that it takes over, the way that its tap roots go down to the centre of the earth etc etc. But the blue of its flowers is pretty much unmatched, especially at this time of year, and it is much favoured by pollinators, so that seems like a win to me! In Alien Plants, Clive Stace and Michael Crawley point out that in sensitive habitats, green alkanet can form a monoculture that excludes other plants, and it’s certainly vigorous. They also, however, point out that no native plant in the UK has ever gone extinct because of an alien ‘invader’. For me, I think it’s all about the vulnerability and fragility of the habitat – I love seeing green alkanet in the city, where there’s already an ecosystem of outrageously tough, prolific and hardy plants, but if it took over the undergrowth of my local ancient woodland I would be a little bit less impressed.

In London, green alkanet is the 6th commonest non-native plant (Buddleia is the commonest, you’ll be pleased to hear), and in suburban Berkshire it’s also the 6th commonest, with sycamore being the most often seen. In East Sutherland in the North of  Scotland, however, it doesn’t appear on the list at all – we know that it doesn’t like acidic soil (see below), so this might be the main reason. It might also not be suited to the colder habitat – it comes originally from Western Europe, so I imagine that it’s used to a milder climate. It seems to like urban streets and also motorway verges, so it’s clearly not scared of a little concrete. Stace also describes it as a ‘wall alien’, meaning that it’s a plant that is often found along the bottom of walls, a most peculiar habitat but one that a variety of London ‘weeds’ have taken a liking to, including yellow corydalis and ivy-leaved toadflax.

Incidentally, green alkanet’s Latin name, Pentaglossis sempervirens, means ‘five-tongued’ and ‘ever green’. I’m guessing that the five tongues refers to the petals, and the ‘ever-green’ to the plant’s habit of popping up at any time of year. Seen amongst the dead leaves of autumn, it really is a most toothsome colour.

And look what I found! A poem, and a good one too. See what you think.

Green Alkanet by Meryl Pugh (from her book Natural Phenomena)

From the hot flank of the bus to the pavement lunch between meetings
in the dazed, hot, infinite day of August:
green alkanet in profusion, persistent, taken for granted
between brick wall and tarmac, on vacant sites,
untended verges.
The hairy, blistered leaves,
the robust, fluted stalk; green alkanet in flower stares
with clarity brewed in a white day-for-night pupil – where world
is altered, reversed – and holds in its blue, pitiless iris
the same, blue intensity that drags us, thrashing, on –

And so, let’s move on and see what I said about green alkanet in my first Wednesday Weed, back in 2015.

Green Alkanet (Pentaglossis sempervirens)

Green Alkanet (Pentaglossis sempervirens)

Dear readers, if the county plant of London is the Rose-Bay Willowherb, then the Postal Code Plant of East Finchley must be the Green Alkanet. As I wander the streets, it seems to be obligatory to have at least one of these hairy-leaved beauties peering out from under the Buddleia, or popping forth boldly from the bottom of a fence. And yet, I cannot remember it from my childhood in East London, so I wonder if it has a preference for the heady heights of North London.

IMG_1883It is, in fact, a member of the Borage and Comfrey family, and, as you might expect, is popular with bees, especially early in the season when there isn’t much else about. Its leaves survive right through the winter, hence its Latin moniker, sempervirens, which means ‘always green’.

IMG_1887Green Alkanet was introduced into gardens before 1600, and was first recorded in the wild in 1724, so it has been with us for a long time. It is a true Londoner inasmuch as it can’t abide acidic soils, and so the cold, claggy clay of the capital suits it down to the ground (literally). It is a very hairy plant – the stems are hairy, the lavender buds are hairy, the leaves are hairy (and sometimes feature white spots as well). It is readily attacked by rusts (as in the specimen above). All in all, it is something of a bruiser, a street-fighter of a plant whose toughness belies its delicate flowers.

IMG_1888‘Alkanet’ is an interesting word, thought to derive from the Arabic word for the plant-based red dye Henna. The word is also the root of the names of Dyers’ Bugloss (Alkanna tinctoria) and Common Bugloss (Anchusa arvensis), to which Green Alkanet is closely related. In fact, Anchusa is derived from the Latin word for paint. The  books that I’ve read seem to agree that a red dye can be extracted from the sturdy root of the plant, and the WildflowerFinder website, which has a special interest in plant chemistry, goes further, suggesting that the extracts from the root can be used to make a purple or burgundy dye, with alkaline compounds being used to increase the blue pigment, and acid ones turning it red again. There is also a strong suggestion elsewhere that the plant was deliberately introduced to provide dyes for cloth, being cheaper than true Henna, which is extracted from the Henna tree (Lawsonia inermis).

The Henna Tree (Lawsonia inermis)

The Henna Tree (Lawsonia inermis)

Green Alkanet has several other uses – the flowers are apparently edible, and I can just imagine them frozen into ice-cubes and clinking away in a gin and tonic. Being a member of the comfrey family, the leaves can also be composted, or rotted down to provide liquid fertiliser. But it’s as a plant for pollinators that it finds its true vocation, the white heart of the flower acting as a target for all those thirsty early bees. It is yet another of those plants that we would be delighted with if we planted it deliberately, but which is undervalued because it’s just a ‘weed’. It seems as if we find it difficult to appreciate the beauty that comes to us for free, like grace.


2 thoughts on “Wednesday Weed – Green Alkanet Revisited

  1. Anne

    “It is yet another of those plants that we would be delighted with if we planted it deliberately, but which is undervalued because it’s just a ‘weed’.” You are spot on with this observation. A blogger asked me the other day if the wild flowers I was featuring was a ‘weed’ – what IS a weed? A plant growing where it is not wanted? I think many of us underestimate the beauty and value of our indigenous plants in favour of ‘garden plants’ nurseries and seed companies encourage us to grow. These conform to a a common understanding of a ‘beautiful garden’. One thing that years of drought have taught me, is that I now value any flowering plant that seeds itself in my garden, be it an indigenous one or an ‘alien weed’ – as long as it is good for pollinators and provides me with the pleasure of a tiny flower or two 🙂

  2. Alittlebitoutoffocus

    Rather perversely, green alkanet is one of the few wild plants that I can remember the name of – purely because the flower is blue. Isn’t it strange how the mind works! 🤔 We have them in our garden, around our vegetable patch, and I certainly wouldn’t class them as a ‘weed’ as they’re too nice to look at.


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