Wednesday Weed – Mahonia

Every Wednesday, I hope to find a new ‘weed’ to investigate. My only criterion will be that I will not have deliberately planted the subject of our inquiry. Who knows what we will find…..

Mahonia aquifolium

Mahonia aquifolium

Dear Readers, there is no doubt at all that Mahonia (or Oregon Grape as it is often known) is largely a plant of parks and gardens, but I found this individual right on the edge of Alexandra Park and the north London Parkland Walk, where it appeared to be making a break for freedom. It is originally a plant of North America, and is named after ‘the first nurseryman in America’, Bernard McMahon (1775-1816) who curated the plant collection of explorers Lewis and Clark. The plant arrived in the UK in 1823. By 1874 it could be found in the wild, and it is sometimes deliberately planted as cover for game birds (much as snowberry was). With its spiny evergreen leaves, yellow flowers and, later, its bloom-covered blue berries, it is one of those plants that has some interest in every season. It also seems to tolerate clay soil, and so there are some very fine examples of the plant in East Finchley.

IMG_5349The plant has a lot going for it as food for animals. It is recommended by many organisations as a food-source for early emerging bumblebee queens and solitary bees. The flowers have a rather pleasant smell too. The berries are liked by blackbirds and mistle thrushes. The leathery leaves are also, surprisingly, a food plant for moths such as the Bright Line Brown Eye (once again, I am in love with the names of moths) and the Peppered moth.

By Rasbak - Own work, CC BY-SA 3.0,

A Bright Line Brown Eye moth caterpillar….(Lacanobia oleracea) (Photo One – credit below)

By ©entomart, Attribution,

…and when it’s all grown up (Photo Two – credit below)

CC BY-SA 3.0,

Peppered Moth (Biston betularia – white form) (Photo Three – credit below)

CC BY-SA 3.0,

Peppered moth (Biston betularia – black form) Photo Four (credit below)

However, mahonia is not only food for visitors to the garden – the ‘grapes’ have been used as human food. In North America, many native tribes ate the berries raw, whilst some turned them into jams and jellies, and others dried them. Should you have a superabundance of mahonia in your garden and an urge to knock up some preserves, you can find all the details you need at the Backwoods Home website. However, as many tribes people only ate the berries as a last resort, we can maybe assume that, whilst a useful source of vitamins, they are not as palatable as you might hope.

By The original uploader was Meggar at English Wikipedia - Transferred from en.wikipedia to Commons., CC BY-SA 3.0,

Mahonia berries (Photo Five)

The wood of mahonia is bright yellow, and produces a dye of the same colour, while the berries produce a purple one. Richard Mabey notes in Flora Britannica that one young boy used the juice from the ‘grapes’ as very convincing fake blood. One can only imagine how much the child’s mother appreciated his inventiveness.

IMG_5456Mahonia has also long been used for everything from gastritis to syphilis by the native peoples of North America, and  there have also been some promising recent studies into its use in the treatment of psoriasis. Indeed, much as I hate to publicise it,  mahonia medicine has even made the hallowed pages of the Femail section of the Daily Mail. Why it’s in the ‘Femail’ section goodness only knows. As far as I know, men get psoriasis too. But it’s probably just as well not to get me started on gender differentiation in the media. We could be here all day.

IMG_5454And there is one more thing to mention about mahonia. Some plants react when touched – the ‘Sensitive plant’ or mimosa is one example. We had one in a pot when we were children, and I remember how the poor plant would behave when we touched it, the individual leaves creeping together as if terrified and then the whole ‘branch’ collapsing . How we laughed, spawn of Satan that we were. Well, New Scientist reports that more than 100 species of plants have touch-sensitive stamen, and that mahonia is one of them. On the Digital Botanic Garden website, there are photos of the stamen contracting after being touched – the theory is that this helps to force pollen onto the legs of any visiting insects. This is a remarkably quick reaction, taking less than a second in warm weather. We often think of plants as being slow-moving organisms, but the more I learn about them, the more I realise that they are intensely reactive beings, responding to their environment with great rapidity when necessary. Let’s never underestimate our flora. They’re a lot more dynamic than we give them credit for.


As usual, I’d like to credit Richard Mabey’s ‘Flora Britannica’ and Sue Eland’s ‘Plant Lives‘ website for providing invaluable information.

Photo Credits

Photo One – By Rasbak – Own work, CC BY-SA 3.0,

Photo Two – By ©entomart, Attribution,

Photo Three – CC BY-SA 3.0,

Photo Four – CC BY-SA 3.0,

Photo Five – By The original uploader was Meggar at English Wikipedia – Transferred from en.wikipedia to Commons., CC BY-SA 3.0,

All other photographs copyright Vivienne Palmer

15 thoughts on “Wednesday Weed – Mahonia

  1. Ann

    As always you’ve found so much interesting and diverse info, but the final photo had me laughing aloud: what a gem!

  2. rosni3

    I had often wondered about this plant which I’ve seen around London a lot, and now you’ve given excellent and varied information. Thank you, and for the great photos – I too laughed at the last one.

  3. squirrelbasket

    Nice one! Although the Mahonia x Media in my own garden is definitely not a weed. One of my favourite shrubs for all the goodness it gives the insects and birds. We often have red admiral butterflies on it on Christmas Day.
    And I love the last picture – reminds me of a cartoon I once saw with the sign “heavy plant crossing” and a picture to match, which I’m sure you can imagine.
    All the best 🙂

    1. Bug Woman

      Thank you, Squirrelbasket! And yes, I have two mahonias growing myself – I was looking for details of a study I’ve read that said that mahonia is the most important urban source of early-spring nectar and pollen, but I couldn’t find it. Note to self – make notes when you find something interesting!

  4. Anne Guy

    It’s a very sculptural plant especially if you prune the stem bare of branches…it also has amazing yellow sap when cut! Thanks for this another great article about a much overlook plant!

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  6. Sarah

    As well as bees, our Mahonia is proving a magnet for blue tits this winter. They seem to attack the flowers and are presumably eating the nectar. I’ve also seen a female blackcap doing the same.

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