Pictures aid in diagnosis.

Beyond that, contact the San Diego County Master Gardeners for info. Contact info is here: http://ucanr.edu/sites/sdmastergardeners/

Also, you'll get a buckets worth of search results using the phrase

"how to establish california native plants" -- but omit the quote marks.

In hot inland areas, Yankee Point Ceanothus would like some afternoon shade and summer water (1x a week). If you don't have some shade in your yard, this may not be the right plant for your area. I have made the same mistakes, trust me. Check out Las Pilitas for information on most natives - http://www.laspilitas.com/nature-of-california/plants/151--ceanothus-griseus-horizontalis-yankee-point

When did you plant your manzanitas and do you know what variety you have? I live in one of the hotter inland areas in Northern CA and I have 4 manzanitas in my yard. I watered them deeply every 7-10+ days for 2 years. You want to make sure the soil dries out before watering again, so check it with a moisture meter to see when it is time to water again. Also, it is best if you don't water either of these plants on a hot day. Both are susceptible to soil pathogens that thrive in moist, warm soil.

I have redwood mulch around all my plants. I have heard some plants really prefer decomposed granite around them (like buckwheats) but I haven't done that. Just make sure the mulch is pulled back from the base of your plants.