 There's a couple things you can do that are fairly simple, fairly easy. The first one is to get a good sprayer nozzle for your hose and get on the underside of those leaves and just knock the aphids off. Aphids do fly, but a lot of the ones that are causing damage have not got wings developed. If you knock them to the ground, they're never going to get wings developed. They're going to just die on the ground, even in the grass. Grass is not very susceptible to aphids.