another mystery plant.

Answer to Fennel - if you eventually discover that your mystery plant is indeed knapweed, then beware! We have it in our wild/meadow garden, and were very happy at first, as it looks well when in flower - thistle-like without the prickles - and the goldfinches loved the seeds. But year on year there was more and more of it, to the extent that other desirable wild flowers were being crowded out. So, regrettably, we have started to fight against it, though I reckon it will be quite a battle! I note from comments on the internet about it, that it is actually "illegal" in parts of the US.
Sorry to anyone who has it in their garden - hope this hasn't been too down-heartening.

Please could I join this discussion too! This plant behind the Buddelia looks like a weed, but has a thick woody stem. Does anyone know what it is? I have marked it in the photo.

Can I suggest that you use the app "Google lens". Just point the phone/tablet at the plant and Google will tell you what it is.

Really clever

Lindsay10 - I tried using google lens on the photograph you posted, and it has suggested March cinqufoil

Haven’t read all the thread so apologies if someone had said this.

There’s an App called PlantSnap. If you download it on a smartphone or an iPad you can take a photo and this App will identify your plant. It’s free.

Shysal: teasels have a line of sharp prickles on the underside along the central vein of the leaf. It's a biennial, flowers in the second year, the bees love the flower heads and the birds like the seeds afterwards. The Romans brought it over for teasing wool for spinning. They grow tall.

Tickledpink, it is difficult to make out the plant in your picture, but could it be Rosebay Willowherb? They pop up here and there in my garden.

Teasels self seed like crazy so be ruthless with seedlings! However, birds love the seeds, so I leave the seedheads on. Mine grow to a good 4 - 5 feet tall and are viciously prickly on the stems and leaves. Perhaps Fennel has a tamer version. It's one of those plants that is on the cusp between weed/ornamental.

I think the plant growing through the buddelia is definitely a common wildflower/weed. I recognise it but don't know its name. It's not rosebay...

The flower heads have turned blue now on ours, so looking more like sea holly.
They're not big enough for teasel.

Anyone know what this is?

The flower.

My bet is one of the nightshade family not a common one but seeds are easily spread by birds

Ýoure right David, Nicandra or apple of Peru.It came from a NT garden and I grow the seeds every year. NT has not regrown it.

Tiny flower, is it a cultivated variety or a weed, apart from potato’s and tomatoes my nightshades are weeds

Lots of nightshades are poisonous at some point.

tickledpink, could your mystery flower be Geranium Robertianum? It has several common names, storksbill, red robin, death comes quickly to name a few, although it's not easy to make it out from your photo.