I had many plants mutating without any special treatment or maximum after treatment with acaricides - leonotis nepetifolia became variegant, datura inoxia too, in case of datura the babys of that plant were also variegant, and in case of leonotis there were obviously a division of chloroplastes or whatever - 90%seedlings were usual green, 10% were totally without chlorophill(white) and died after 10-14 days (how they could persist so long). But among those 90% several plants showed signs of variegancy later, but i could not glean their seeds because of frosts in autumn.
My heimia, calea and origanum vulgaris plants once developed a "threebranchness" when each point where side branches form gave not 2 as usual, but 3 of them going in all 3 directions. But the branches did not contain this adnormality, so it was observed only for their stem.