Another interesting weed: Geranium robertianum
It was not that long ago that I enthused, to the derision of some readers, over a double-flowered hairy bittercress seedling. I am sorry to relate that it did not set seed, as I feared it wouldn’t, but it hangs on and keeps producing flowers so I have tried to take cuttings – I know, it is a kind of madness!
You can read more on the original post – Double bittercress
So it will not come as much surprise to learn that I am featuring another weed today. Few native plants (weeds) have much potential as garden plants (though I know there are notable exceptions) but one of the prettiest is one of our native geraniums. Geranium robertianum (herb Robert) is a common weed that spreads by seed. It is not something that most people want to introduce into the garden because, though pretty, with small, pink flowers and red stems to the ferny leaves, it seeds prolifically, chucking the seeds around in typical geranium fashion. The whole plant is also aromatic – to be generous. I have, in a previous life, grown the pure white ‘Album’ from seed and it has stayed with me since, even coming with me (unknown) across the Irish Sea in other pots and appearing now and then.
But today’s plant is not that but a variegated form. Several years ago I found a variegated seedling and dug it up and potted it. It grew well, with very randomly variegated leaves. Some were part white, others all white and others green. The white tissue is enhanced by the red pigment in the plant, making it look pink at times and salmon orange at others. The original plant died – it is biennial – and I allowed it to seed naturally and have now dug up the three best seedlings to grow on together. When bigger I will plant them out and see how they do – and if they produce a decent proportion of variegated seedings. If it does I think this could be garden worthy. I can’t find any reference to a variegated G. robertianum so maybe it is new.
February 2023 Update
Well, several years on and I can report that the variegation proved unstable and obviously recessive. I now have a clump of seedlings and none are variegated. I will keep a close eye on them and will thin them out and allow a few to flower in case those genes are still in there somewhere. But I can’t let it spread too far. Another great idea that didn’t quite come off!
The Biking Gardener 
I have a white flowered one too! I saw a ton of them in a derelict front garden in town. Nipped in and pulled a couple out and potted them up to see if they seeded true – which they have done – so far. I have them planted out in one of my wilder areas. I could find no reference to a white one in any of my books. I should have guessed you’d know about it! Good luck with your variegated one.
LOL. It is a bit of a thug but, as you say, in a wild (ish) area it could be useful. I hope you survived the wind OK
A Geranium robertianum ‘Celtic White’ did the rounds for a while and it was well able to do those rounds for it self-seeded with great vigour such that we made every effort to eradicate it after the first year. It was pretty but it was also everywhere!
I was wondering if mine was ‘Celtic White’ – it may well have been. It was a pretty little thing but a bit too fond of itself. Sorry to see the damage in your garden and your poor cornus.
It is actually sown ‘intentionally’?! It showed up here a few years ago. Fortunately, it is reasonably easy to get rid of. I really dislike the aroma. I do not find it visually appealing. It does not bloom well here.
Wow, this is an exciting find! I hope you have success with this summer’s generations.
Thank you – I have a few seedlings coming along – look bright at the moment