Overwatering and underwatering exhibit the same symptoms. If it’s underwatering, you need to give it more water. If it’s overwatering, there could also be some sort of fungal infection going on. That will clog up the water vessels and prevent them from conducting the water that the shrub needs. If you can, get under the shrub and dig down about 6 inches . You should be able to judge then what your water situation is. Another possibility is that you have very heavy (clay-like) soil and the water is not percolating down through the soil and the shrub is sitting in a bathtub like environment and the plant cannot breathe; it is drowning. Ceanothus should not need more than occasional watering besides rainfall. It also look like there is considerable undergrowth. You might want to consider trimming these shrubs back in the spring. Trim the previous season’s growth by about one-third in spring. More if needed.