Valisnaria flowering in my diy pond

[Danlacey1988]

So I this year I started off another tub pond project but this time I add some valisnaria and for a while It did what I suspect to be nothing just one plant then suddenly it grew loads of runners and other plants which is great
But then it did something I've never seen before from my ponds and aquariums

And it started to flower now I've never seen this before I need to get a picture really
And was just wondering if anyone else has had this happen
All the valisnaria I've grown has never flowered