you only get gold roses from watering wilted black roses. gold roses do not breed
it's a shame really, the easier way to get more gold roses is to buy/trade from other people. i ended up losing a lot of blue roses & black tulips because i forgot to water them while trying to get more gold.
When I was trying to get gold roses I ended up having to put the rest of my hybrids into storage until I'd got as many as I wanted. It's a pain they can't be bred but I did find it easier to get a lot of them, I really struggled with other hybrid types