Q.Bluing Rose Petals
Yours faithfully, I can’t understand the mechanism of bluing in rose petals.Also i can’t find a photo of a real “blue/bluish” rose.I found that petal bluish is senescence symptom.The red petal colour gets blue.This change is due to lack of tanins in cellular juice of the petals,on high level on pH of the juice, the high levels of anthoxanthines to anthocyanins and in high lever of potassium (K). Unfortunately, I can’t find a citation for this. Is this true?Does bluish/blue rose exist and how they look like? Thank you in advance.

Certified GKH Gardening Expert
According to our rose expert there are no true blue roses. There are some roses with names that sound like they are blue, such as Blue Dawn or Blue Angel, but they are generally more mauve or lavender.
https://www.gardeningknowhow.com/ornamental/flowers/roses/black-roses-blue-roses.htm