I do not know of any weed killers that will kill the clover and leave the sedum unharmed. You will need to dig up the sedum, carefully dig the clover and then replant the sedum. There will probably be some regrowth of the clover, so keep an eye on it and dig it out. The mistake you made was not going after the clover the minute you saw it. Wish I could give you a better solution. Best Nancy
How To Remove Clover From Seedum
Question From: MICHIGAN
Q: I have John Creech Sedum planted for 2 years and it looked great. Its in an isolated area ( next to the walkway towards the front door and house). Last year I noticed some clover had popped up and I saw it spread. I am asking if there is a way to get rid of the clover. People have told me I have to take up everything, or paint every clover leaf, but its way too time consuming. Others have told me there is no way to kill only the clover and not kill the Sedum. What are my options ?