Above, the bulrush that's growing near the bottom of the middle pond. On the left, 2 weeks ago, on the right as it was this morning. I was as bit further away with the camera at the beginning of the month, but nonetheless you can see that it's grown quite a bit. Below, the one on the pond margin, also doing well.
I can't explain why I'm watching the progress of this particular plant so keenly. It apparently has many uses, according to the sort of blokes who like to go back to nature. I'm not growing it as a crop, though I will try the roots, just to see what they're like, if and when I've got lots growing.
Maybe I can explain it. If these two plants grow, and seed the whole pond, and grow to their full height, they'll be a standout allotment feature. Just now, after a rather dry month, the pond is just a muddy hole in the ground, and that's probably how it's going to be for several months of every year. But it's doing its job, the Middle East, Midwest and North West beds are all well drained now. I don't know, but it's likely they'll be draining well over the winter, too.
So that's the utility of it. But allotments can have features which are useful, first, but can also have aesthetic value, maybe you can even say they can be beautiful. And a few dozen 8ft high bulrushes in a small pond will be beautiful.