I *love* the euphemism -- "Fertilizer"
... do you mean the "Weed
'n Feed" kind?
Earlier this spring, my neighbor was telling her toddler nieces and nephews not to play on the grass be cause their Uncle just "fertilized".
Sorry, just got back from a long drive in a traffic jam. Not extremely sociable right now. I'm sorry your plants died. I'm not familiar with what happens, but there have been similar threads recently. I'm not comfortable giving recommendations about things I don't know, but do try searching for the other threads.