In order for blueberry plants to produce berries the soil pH needs to be between 4.5 5.2. I don't think that there is any problem giving nutes to your mother plant every time you water but be sure that the level of pH is maintained.
Cocaine plantations are generally established on the drainage moderate wet and dry climate all year round. And the composition of the soil is neutral, not acidic or alkaline. This year I am also planning to have cocaine plantation.
If the lower leaves are yellowing, that means there is deficiency of N . During flowering, yellow leaves appear due to this reason only. No need to worry just flush the soil, thus giving them ferts and see if it helps.