I've never heard of being about to change the color, so if it's possible, I'd like to know, too.

You can change hydrangea flower color, but hibiscus (?).

You can somewhat modify the color by use of heavy use of some nutrients, but you can't make any meaningful changes.

OK, if you can't make any meaningful changes, how do they have different colors for sale? I mean, is it something you do with a test-tube, grafting, or something?

Something very strange has happened to my purple hibiscus. Every year new baby plants grow, so I replanted some to an area about 20 feet away - same exposure. However, one of the new plants has white flowers on it. Also, the purple hibiscus has five petals, while the white flower has only 4 petals. The leaves are slightly different. I don't know how this happened and searched this site. So I guess I did get a different colour flower - only have no idea how this happened. Any ideas?

They create different colors in hibiscus by hybridizing. They propagate the new varieties by rooting cuttings or by grafting - in other words, cloning.

I've had a weird experience with an all white hibiscus. One flower opened with three petals a deep rose colour and the remaining two white, and another flower opened with four rose petals and one white. The rest of the flowers remain white with a magenta centre.
We've a red hibiscus growing close by, but does anyone know what causes this? Is the colour going to revert to red or pink over time? I've some photos if anyone is interested in seeing this.