Q.How To Get Rid Of Aphids At The Roots Of My Gardenia Bushes
I have tried to spray many times. Finally I poured anti-aphid liquid around roots. It did help a little but not totally.
Ladybugs, a strong stream of water on the upper/lower leaf surfaces/branches and neem oil/insecticidal soaps/horticultural oils are usually good counter measures to use against aphids. But you must follow product directions closely and repeat for long periods: https://hgic.clemson.edu/factsheet/gardenia-insects-related-pests/