It does look part sick or dead, but I do see some new growth at the base in the first picture.

If you replanted when its been hot it might not be able to take in the water. It looks like it might be planted a bit too deep in the ground. The top of the root ball should be even or just slightly above ground level. Did you by chance fertilize---never fertilize a sick plant. it doesn't look like any bugs or other disease infestation.

Yellow leaves can be over and underwater. Usually underwater leaves are yellow, dry and crispy and over water they are yellow and limp. I do think keeping in partial shade when newly planted was good. It also depends on your soil. It is draining well or is it sitting in mud underneath.

If you have a tester check it, or just a stick will do. You should be able to tell how soft/moist the soil is.

I haven't been lucky with type of salvia...I recognize the leaves.

Not sure how often your watering but I water my salvias twice a week in the summer time.

It looks to me like it was over watered at one time. What is the cultivar and how long ago was it planted?

I agree overwatered, yellow leaves. Drought stress shows as grey dehydrated leaves.
Carla in Sac

Thanks everyone. It was planted about two months ago. The soil drains very well, so I think I have just been overwatering. Some of the plant has dried up now since I've cut back on water but the new growth at the base is still strong and deep green, so hopefully it's beginning to establish itself despite my interference.

I don't remember the exact cultivar- it was something I picked up at Home Depot. I'll post an update soon if anyone is interested. Hoping I can start interpreting the signs it gives me correctly so I can get it back to producing those lovely purple blooms!