I LOVE PEONIES
First question do you have the peony or the peony bushes? The peony can be cut and make great flower
arrangements if you can get rid of the ants. The bushes are an entirely different matter. Be very careful cutting those because they are a graft and you can easily loose them.
Now some basic information about your peonies environment. What is the pH peonies like 6.5
How much sun are they getting? I would go for full shade in southern california because peonies really like cooler weather. In fact to get good blooms you really need a cold period. How your going to manage that in Southern California I don't know.
Peonies need to be buried only one inch below the ground. Any more than that and they will have a hard time getting above ground and that will reduce the number of blooms you get.
Peonies love bonemeal. Try scratching some into the soil around the plant and then watering it in well.
Since they are only a few years old you may want to cut off the buds this year to get a better crop next year. That would be a very hard decision to make but it could work for you. The better established they are the more blooms you get.