Why would a mum block a friendship? Playdate exclusion

Yes but she doesn't have to give her time to something she doesn't want to do, nor her child's. Honestly I think you're overthinking it. It hurts to be rejected but it may not even be personal. It could be she just doesn't have time or headspace to dedicate to you and your child because she prioritises other commitments and that's reasonable. You can't control what other people think or get them to do stuff they don't want to do so there's no point trying. Just let it go. They can still be friends at school.

OP I really do get where you are coming from .This happened when my son was at primary school. He was in a solid friendship group throughout and one Mother was really Off with me ,absolutely no idea why .
Her son did come to us after school occasionally but my son never invited there or very rarely.
We live in a reasonable detached house with decent garden but this child lived in a massive house with pool etc .
This child had a summer party when they were 10 and all 6 boys were invited apart from my son . Found out after the event.
This happened about 15 years ago and I still very occasionally think about it ,looking at what an amazing young man he has become.

Are you much richer or poorer than the other family?

OP I had the same deal with one of mine - I didn’t fit in that particular clique and my son was excluded - emails and invites ignored . I told my son the truth , he’s now almost 15 and he and the other boy are still best mates - from year 6 / year 7 they make their own plans and do stuff together and mums don’t have any real impact . If this is a real and local friendship it will last . Not all people are nice and some have their own issues - 9 is not too young to start learning that - they spend time together at school - a little patience is needed - these things do sort themselves out

There are definitely friendships I have discouraged for my daughter. One in particular springs to mind. I'm absolutely certain that her mum would also describe her as lovely and kind, but the reality is quite different for my daughter. It was a bit of a "frenemy" situation. Best friends one day, my daughter being pushed aside the next. Comments on my daughter's clothes. Pointedly leaving my child out of group games but then intermittently "love bombing" her with friendship bracelets etc. All very standard but not something that was healthy for my child. I'm absolutely positive that her mother would not recognise this behaviour in her daughter. The other girls in the group are still welcome at my home for occasional playdates but I will not extend the invitation to this one and have encouraged my daughter to stay well away from her at school.

She obviously has her reasons for not wanting to facilitate the friendship between your children. Maybe there's some superficial reason but maybe she has genuine concerns. You'll never know and she is free to make the choices that she feels are best for her child.

Op I don’t think you can make assumptions, she might have seen or heard something she’s not happy with or maybe something happened in the friendship group (your daughter sounds lovely but nobody is perfect so maybe they had issues you didn’t know about). There’s only so much facilitation you can do but do maybe try and have a conversation with the mum asking about a play date directly

There is a fair amount of "social engineering" at primary school where some parents will steer friendships towards families they feel comfortable with. The reasons aren't always obvious. Sometimes it's snobbery, sometimes it's shyness/anxiety. But there's nothing you can do about it. The good news is once they go to secondary school the kids can get on with it and the other crap falls away.

There's no benefit to tying yourself up in knots trying to figure out a reason.

Maybe she doesn't like you. Maybe your child has upset her child at some point. Maybe she doesn't like your husband has heard a rumour, or maybe she's just a bitch.

You'll never know the reason so there's no benefit in stressing yourself out over it.

don't know how to explain adults strange ways to mine when we teach mine and the school teaches them to treat others nicely.

But you don't need to offer any explanation mostly because you don't know it. You don't even know if it's strange, it could be perfectly valid.

'I have absolutely no idea darling. Carry on playing with him at school, and let me know if there's someone else you'd like to invite instead.'

I'd just be honest with DD and tell her you don't know why. You don't -it's not a lie. Tell her it's nothing she has done and then encourage her to invite others over. She'll be fine. She can still play with her friend at school. There's no point wasting your time trying to figure out the mind of a stranger who isn't interested in engaging with you.

It feels wrong to you but presumably she has her reasons. Maybe she just doesn't like you or your child? Sorry if that sounds blunt but it's really her decision and while you feel sad for your child, you just have to accept it. I would encourage your child to spend time with other friends.

Could be any number of reasons which you don’t know so best not to worry about it and just say to your child they’ve got a lot on.

I avoided play dates with one child because of some issues with one child that the mum seemed fine with, but don’t like confrontation so just said we had something else on was too busy for a while then she stopped asking again. I know it’s bad.

Encourage DC to branch out and invite others round instead. They are getting to the age where parents tend to have less control and they have more independence when it comes to socialising outside of school and making their own decisions with who they spend time with.

Has this child and yours ever had any kind of falling out? Wondering whether the child may have ever said something negative to their mum about yours before?

People are just downright odd.

But one mum once told me , that she normally wouldn’t have been friends with me at all, because I had daughters, and she had boys, but wanted a girl…!

Another one, because I had more than one child, and they really wanted another, but their husband wouldn’t. !

Another Mum complained about my daughter being friends with a girl, in infant school, who lived near her daughter, and that it was spoiling their friendship as the other girl wanted to play with my daughter not hers.

As I said, very odd people about.

No idea op and there's is absolutely zero value to speculating unless you have absolutely nothing to do I guess. Especially as you seem inclined from your responses to want us to say something negative about her, based on nothing really. They'll be organising their own friendships outside of school very shortly anyway.

If she is that way inclined, she'll be managing that friendship til they're 18

It's her problem, not yours. Don't let it worry you -arrange play dates with others and forget about it. If she isn't going to address it you can't do anything about it anyway so it's pointless thinking about it and wasting your time guessing what's wrong. She doesn't like you -oh well 🤷‍♀️. In a few years they'll all be off to secondary and you won't see the mum or think about it again.
I had a mum dislike me for some odd reason at primary. We had only ever been on a hello and goodbye level of socialising anyway, so when she started ignoring me and giving me dirty looks I laughed and let her get on with it. I completely forgot about it for a few years until she started saying hi again. Obviously my total non reaction became boring after a while!