By what metric? looking at the census data, it appears the poverty rate of California, while not great, is certainly not the worst.
https://www.census.gov/data-tools/demo/saipe/saipe.html?s_ap...
http://www.politifact.com/california/statements/2017/jan/20/...
http://www.politifact.com/california/statements/2017/jan/20/...