Hello there, i'm growing a zinna this year called Zahara Rose Starlight, it supposed to be with with like a pink colour in the centre. I have sowed 4 plants from seed and 2 plants have just started flowering but they are just plain white. I did a browse online and it said they been suffering from heat stress but it has not been above 20c recently so I'm confused to see that as the person said it needs to be above 32c for this change to acur. If anyone has grown this plant or knows whats wrong can anyone let me know, i'm really curious now. Also if anyone is good with dahlias, i saved seed last year from a mixed colours I was growing which included yellow,red and purple. This year it has come up plain white also. So once again if anyone has any thoughts it would be good to hear. Thanks everyone and happy gardening .
My memories of growing Zinnia was that most of the time the weather was not warm enough, so I'm doubting its heat stress. I think you need to wait for later flowers to open before making a judgement, as it could be the first flowers are slightly out of character. As to Dahlias grown from seed, its a gamble regarding what colours you are going to get from open pollinated plants.