Lestv said:Would Roundup affect every bloom like that?
Yes, generally when you see irises that have been affected by Roundup (glyphosate), every flower on a given stalk will be damaged. However, you can have situations where only some stalks in a given clump are affected. It depends on when and where the exposure to the chemical occurred.
For what it's worth, Roundup doesn't cause "mutations" in plants. It's an enzyme inhibitor that prevents plants from producing certain amino acids they need to grow and live. Irises are somewhat resistant to glyphosate in the sense they often survive being sprayed with it, but they do absorb it and it does still act as an enzyme inhibitor in their cells and disrupts their growth to the point where they sometimes can't produce normal looking flowers.
