Name of this purple feather duster rail track side flower?

[NewspaperTaxis]

One of these has emerged in my garden after a clear out of brambles - it was always there really but overshadowed.
This plant with its purple feather duster flower is seen in droves alongside the railway tracks as you head south from London into Surrey, all through Balham, Raynes Park etc so I imagine the train movement picks up the seeds and dusts them alongside the tracks, encouraging them to grow.
But what is its name? It's a sort of weed but a rather attractive one.

Is it a buddelia?

Buddleia! and it is a scourge on the railways.

Buddleia. Prolific and bees and butterflies bloody love it. If you plant some make sure to keep it under control and not too close to your house

Yes, it's buddleia.

It’s Buddleia. Produces thousands of seeds which blow about on the wind. Gorgeous to look at, wonderful for bees. Ecologists are against it being grown on purpose because it’s invasive though.

Oops! Slow typer here!

You can get sterile varieties that attract insects but won't self seed.

It's Buddleia, AKA the butterfly bush

I’ve got a couple of mature buddleia and they are an absolute nightmare! I have to hack them back to 2ft tall sticks every autumn/winter as they go nuts (10ft+ tall and wide every year). Insanely fast growers

Thanks everyone! Er, why not too near the house? Are they an insurance risk? Or is it just they take over too much? The one in our garden is a distance away though so that's okay.

It’s a shrub, not a tree, I can’t see it being an insurance risk. They tolerate heavy pruning/coppicing - you can take them down to about 30cm each year.

They grow surprisingly big - I’m forever grateful to my dad for pulling it out when he spotted it by our drive. I thought it was a pretty small shrub, I’m a terrible gardener so it would be huge by now!!

They are a bit of a mare for colonising any chink in your buildings, I've seen them growing out of the roofs of poorly maintained properties.

Love them as a far-end-of-the-garden plant, they're a bit too unruly to look good close up. We have a white one, we reduce it every autumn, and cut it as close to the ground as possible in late April, it's 10 or 12 foot high again now.

@StyleDesperation

You can get sterile varieties that attract insects but won't self seed.

Mine doesn't self seed or sucker. It's getting loads of butterflies and bees at the moment. I wouldn't want to be without one!

Yes keep it. We need as many insect attracting plants in our gardens as possible. The brambles you had are also good for the environment. Gardens don't have to be deadly straight and weeded out of existence.

I counted 12 butterflies, hummingbird moths etc. on mine when it was hotter 2 weeks ago. They're amazing , You can get them in dark pink too.

Keep it, but treat it like mint.

It can be a thug and it self seeds like Billy-O.

It comes in a range of pinks and whites - I love the scent, the insects love it and it's pretty hardy.

Just keep a stern eye on it and prune it back in the autumn.

I couldn't count the butterflies on mine the other day, but there were at least 2 each of tortoiseshell, red admiral, peacock, comma, small and large whites - more like 4 or 6 apiece of some. Lots of bees too.

@ErrolTheDragon it's the same in our garden. We have a couple of the ordinary "railway" ones but they've never given me a single free plant baby!

We also have them in our garden. They are gorgeous and don’t self seed. As others have said, butterflies love them. X

Thanks helliachi

They do need pruning in the autumn, I've been dead heading mine now and they're still reflowering which is great and hasn't happened before, the colours are deeper too, it must be the rain and the odd bit of hot sun in between!

Errol I raise you one zebra striped swallow tailed butterfly!!! It was a few years ago though. I googled it and they only lay on a papaya tree (one we certainly haven't got!) Iam in MW France.

I really like them!

I used to have a lovely buddleia it never self seeded or spread and now it has died. You cut them back very hard every year and they regrow.

Mine generally continue giving a few flowers into autumn. I deadhead and take out straggly branches now as well as a proper prune later.