Do you water when the sun is on the plants? Plants should be watered in early morning or early evening so the water on leaves don't burn them and so they are dry when the cooler night temperatures come.

Have you fertilized them at all? Did you loosen the roots on the bottom when you planted in case they were pot bound.

All or any of these could be the cause of the yellowing leaves and lack of blooming

Yes, I think I have watered them when the sun is on the plants but I do try not to wet the leaves. I will switch to watering early morning.

I haven't fertilized them because all three came with time-released fertilizer in all three pots (two months ago) and because I read that we are not supposed to fertilize in the winter, even in SoCal, because of the lower temps and shorter days.

Now seems like the right time to start fertilizing. What kind of fertilizer do you recommend and how often?

Thanks!

You are right, chloebud, ivy geraniums are much easier to grow (and they do look nicer too) but because I've never had good luck with them in the Northeast, I wanted to give them one more try here, in sunny and dry CA. The funny thing is... Right across the street, there's a slope that has been difficult because of irrigation problems so the gardening crew planted several dozen zonal geranium plants, small ones, three weeks ago. I was sure they would not do well and yet there they are, getting water every night and looking great. We'll see what happens if/when those plants take off. I remember how beautifully green and full of flowers potted zonal geraniums looked in central Europe. I should've asked the people who tended to them to share their secrets with me :).

Zonal geraniums become actual shrubs in SoCal!! They should do fine and require minimal attention. There are no "secrets" to growing geraniums/pelargoniums - all they require is sun and watering when the soil dries or the temps climb. Unless they are being grown in a container, they don't even require much in the way of fertilization.

Ivy geraniums love SoCalifornia climate. I find that consistent watering will get you lush growth. In summer, esp. some will turn yellow and drop a few leaves if I take too long to water (sometimes every other day depending on soil) but, they hang in there. Very forgiving.
Don't think you'll have any problem growing Ivy's, here.

If youre in the fire zones, they did suffer, but with some fertilizer, water, and sun, they are coming back

If you are in or near the January fire zones, the plants suffered too

Take off the dead leaves, give it some fertilizer, water, and sun. Dont over water