They can also be yellow or orange in the early stages. Getting rid of the ants so that the predatory insects can do their job is an important part of a good aphid control program. They typically reside on the underside of leaves or along the stems and bases of the plant. STEP 2: PREVENTION Introduce beneficial bugs. Spray hibiscus infested with non … Be careful not to damage the plant with a heavy stream of water. Apply dormant oil. Control ants by trimming the lower parts of the plant so that they don’t touch the ground and give ants easy access. Coat the lower part of the stem … Aphids start as little black dots then turn into green bugs. If you find just a few on your plants knock them off with a stream of water from the hose. Getting rid of aphids can be quite the challenge. I figured the easiest way to get rid of aphids would be to blast them off with a spray of cold water; so I tried that first. You can also spray the aphids with a mixture of warm soapy water in a spray bottle. Getting rid of these black aphids is not easy work, but if you are persistent, your hibiscus can be aphid-free before the end of the season. Choose neighboring plants strategically.