Anyone ever heard of this before?

My Mum had some roses (and other flowers) in a vase with just water. I went to change the water this evening to find the cut tips of all the roses had either turned white or lost all pigment. I've never seen anything like it. No signs of any disease otherwise. The rest of the roses are green, just the ends (and interestingly some of the thorns that were submerged) are completely white through. I'd put a photo up if I knew how...

Any feedback would be great!
Cheers

Welcome CG, can I ask how long they were in the water before you went to change it ?

Thanks,
About a week in the water.

That sounds a bit long without changing the water, I assume it was just tap water in Sydney ?

Yeah, just rain water in Melbourne actually. I think Mum had a busy week and hadn't had time to change the water.

Stale water I would think, if you cut them above the white line by about 50ml you "might get some more life out of them