I don't fertilize any of my perennials, grasses, shrubs or butterfly bushes. They normally don't require supplemental nutrients. Back when I used to fertilize things I used either seaweed extract, fish emulsion or a solution I mixed up with worm poop & water.

i agree... they are plants.. not children ...

they do not need to be fed.. clothed... educated.. etc ...

especially if you have decent soil ...

i have sand.. and i dont ...

now.. that said.. if you have something in the garage.. a little of this or that wont hurt..

ken

I do have a lot of Oak trees around so the soil I would assume is very acidic

Whether a plant should be fertilized depends on the plant, it is not necessarily a DO NOT FERTILIZE across the board rule. If it is a heavy feeder (e.g. lillies) it is going to benefit from supplemental fertilizer; hydrangeas are middle of the road IME.

Oak trees - or any other plants - do not make soil acidic. Soil acidity is dependent on the underlying soil minerals and the amount of annual rainfall. Plants will only grow in that location because the soil conditions and climate are already to their liking. If you have questions about your soil pH, which can affect nutrient uptake, test - don't assume.

FWIW, lilacs generally never require fertilization. In fact, fertilizers can inhibit good flowering with this shrub.

Sorry, I don't have any advice because I also never fertilize... not even my roses. If the ground they've been planted in is optimum and well prepared, they'll do fine.