For a mild outbreak of aphids just rince them off. Take the plant to the sink and run some water over it and GENTELY brush them off with your hand. Keep an eye on it and do it again in a couple of days. I just got a plant that was infested with the green aphids and it went straight outside and got hosed off. It missed a few but it was maagable enough to pluck the rest off with tweesers. For a natural remedy you can get some Neem oil from HD or lowes and use as directed. Its a natural plant oil that wont hurt the plant/flowers and it treats fungus, bacterial infections insect pests and more!