I have a bank in back of my yard that's 70% is covered with sedum. The cyress spurge has always been around but most times it was a few plants here or there and easy to control. This year for some reason the whole bank is infested with it and it's growing in with the sedum and it's impossible to pull.

The isolated stuff I give a quick spray but I can't spray within the sedum or it kills it.

Any little backyard tricks to get rid of this stuff. I got 2 suggestions, one was a vinegar spray which I am afraid will kill everything. Another was to try dandelion spray and test it ahead of time.

One challenge I have is the worst part of infestation is in an area I can't access because it's too steep to climb. I have tiger lilies and it's mixed in that as well.

Thanks in advance.

It's a problem here as well: the best control method I have found so far is to cut the grass, and cut it often (once every 2-3 weeks), from March to May to force the Spurge to use up its energy reserves, ultimately killing it. After that it's more or less smooth Spurge-free sailing for the rest of the year.

Chemical control is pretty difficult on Spurge because, very much like English ivy and other noxious weeds, it's covered by a wax layer that limits the effectiveness of herbicides. You can get around that by using a surfactant (you can get it at Home Depot or on Amazon).
If used at standard dosage (1X), sulfentrazone-based herbicides cause no damage to Sedum apart perhaps some leaf discoloration, so you should consider herbicides containing that active ingredient.
Bear in mind however that mature Spurge is hard to kill and even when using a surfactant you may have troubles getting through the thick wax layer, so it's always better to hit it when plants are still young.

Thanks for the suggestions and it probably explains a lot. The bank really can't be cut with a mower, I use a string trimmer to do clean-ups. This year has been extremely humid and everything is growing fast. I notice when I cut it down to the root it takes a long time to come back.

Going to try the surfactant in areas I can't reach.

Thanks again