What’s weird is how that one phrase sticks out and feels wrong, but not all the others that are quite similar in construction; ‘gets soiled’, ‘goes wrong’, ‘comes undone’ etc. Some of those might not be exact grammatical equivalents, but I don’t think that really matters - they are less complete than they might be, and we’re fine with it.
From the other side, it’s also weird to have an expression you’ve used all your life be picked up as teeth-gratingly wrong by people who you would swear spoke the same way you do. See also “outwith”, a perfectly cromulent word north of the border that will make people look at you like you’re having some sort of spasm.
I’m not sure exactly what you mean here, but “needs verbing” is standard in most UK dialects, not just Scotland.
The car needs washing.
The dog needs grooming.
The computer needs rebooting.
All standard and unremarkable throughout the UK. In fact, I had no idea that this construction was not used in the US.
Are you saying that the “needs verbed” construction that is a regional US usage is also used in Scotland? I have never heard that anywhere in the UK, but I havent spent much time in Scotland.
I live and grew up in the fuchsia 3-4 area, and for a time was firmly in the middle of the purple 4-5 area. So I’m not unfamiliar. I don’t use the expression myself, but it’s not jarring to hear it.
Definitely, it’s just a situation where you eliminate words while still leaving the full meaning, and it’s “grammatically correct” in the sense that it properly conveys what you’re trying to say.
Actually it is, I hear that kind of talk all the time. “Needs washing” and “needs washed” both sound pretty “normal” to me.
To be clear, I’m talking about the “needs washed” construction in my comment. “Needs washing” is perfectly normal in my dialect, as is “needs to be washed.”
Yes, exactly. It’s used widely. When I grew up, that’s how you expressed the idea that a thing required a change in state. “Needs x-ing” sounded odd. But at some point in my 17 years in England, I adapted and now I’m back in Scotland, get corrected by my ever so slightly pedantic father if I don’t say"needs x-ed".
Oh come on, someone has to say it.
“I say, I say, I say! My dog doesn’t have a nose”.
“How does he smell?”
“Awful”.
I don’t wish to know that, kindly leave the stage.
Yeah, I’m from just over the border (Cumbria) and when I moved south “needs washed” was one of the things I would get picked up on. I remember an old friend with quite the interest in languages (he taught Latin and had studied Greek), also from just over the border (but on the Mackem side) talking about how the verb to be was routinely omitted in English constructions; I can remember exactly the example he gave:
The book, now read, is put away.
j
Mackem: Sunderland, Wearside
It occurs in the UK, mostly north of the Tees, and certainly in Scotland. I first heard it in the Beano, published in Dundee.
Or that other classic:
Inspector Closeau is speaking to a German hotel clerk also played by Peter Sellers in transparent disguise while a small dog is growling menacingly at Closeau’s feet.
Inspector (in English with a bad fake French accent): Your dog, does he bite?
Hotel Clerk (in English with a bad fake German accent): No.
Dog: Snarl, snarl, chomp!!
Inspector (shaking leg madly to dislodge biting dog): I thought you said your dog does not bite.
Hotel Clerk: That is not my dog.
I love that scene.
“My dog just had puppies!”
“Really?! What kind of dog is it?”
“Female!”
Q: Yes, but what kind of dog was it?
A: Pregnant.
Vet: well, that’s the first time I’ve seen that in a male dog. I think I could get rather a good research paper out of this, could make my reputation in the profession!
Do you know how many German soldiers you just killed? And it isn’t even wartime! 
It’s OK, we took precautions. We had the whole of Q division chanting laments over powerful loudspeakers.
I think casualties were fairly light, all things considered…
Many years ago, I had a Scottish boss who used “outwith” a lot. I picked it up, and now I (Yorkshire-based) use it as well. So it’s working its way south one person at a time… 
Wallace’s revenge is slow but sure!
Curiously I also had a Scottish boss who used this term, and I live in Yorkshire.
It is slightly outwith normal English usage, but I like it.
I’ve lived in Yorkshire down to just below the M4 (and now a bit further). I’ve kept my middle-atlantic (aka “newsreader”) accent intact since I was 17.
If someone said “outwith” down here and there wasn’t a good bit of context I am sure I’d mistake what they meant. If I said “outwith”: “I’ve lived outwith Dublin and Bath” people would nod about the crazy Irishman with the odd accent and strange words. So it’ll take some time TwoCarrotSnowman!