Possibly too little water.Especially if near a wall. Use Eco liquid to wash up and put the sink water on it if you wash up by hand, as I do. My ceanothus which is near a wall, under a hawthorn, is thriving on sink water in this drier weather......It has even come up with a few flowers. Ceanothus can be a short lived shrub that does not like being pruned too deep, wind rocked when larger, or allowed to dry out too long. This is our fourth one. We have lost previous ones for the above reasons.