Most plans would not give a tinker’s cuss if you never fertilised them, but there are a few that really do need fertilising.
Citrus need it badly. August & February are the months to feed citrus: a full dose in August (now) and a half dose in February. Without this your oranges, lemons, limes, mandarins etc will not produce many fruit. For the same reason DO NOT grow anything under the canopy of a citrus tree: no grass, no annuals and no groundcovers. Just mulch – and lucerne hay mulch is best.
The other gross feeders (aka hungry plants) are:
Roses, lawns, gardenias and vegies.
You can use citrus food on the roses, gardenias and vegies. Lawns need lawn food – preferably a slow release one like Scott’s Lawn Builder.
Time to think of your CITRUS.