Originally Posted by tlg
Can a lilac tell the difference between a synthetic fertilizer vs an organic based fertilizer?
Yes, and all the lilacs relatives that are plants. Synthetic fertilizers are like sterioids for your plants. They feed the plant and not the soil. That causes lush growth that can attract insect pests. Synthetics leave behind residual salts which organics don't. Synthetics don't contain trace minerals and organics do. You should find this informative.
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.