Many native species have a semi-dormant period during the summer, triggered by the heat. They'll usually drop some leaves and stop growing during this period because they're expecting there to be a lack of water. Some of these plants - such as ceanothus - are also susceptible to root rots, so if you try to water them during the summer and they end up sitting in water, their roots may rot and they'll die. When you transplant something you need to water it to encourage the formation of new feeder roots, so transplanting natives when they're semi-dormant is a risky business, so its usually recommended to plant them in the fall when they're emerging from dormancy.

That said, I've planted ceanothus, manzanita, mimulus and california wax myrtle in the late spring and they've been okay after looking a bit unhappy during the summer. I'm in a slightly warmer area than I think you are, so you might be okay. If you're watering the plants in their pots and they're still growing, they won't be worse off in the ground as long as its well drained. Make sure of the drainage - add something inorganic if you need to - and water infrequently with large volumes if you can. If they're showing signs of dormancy, I'd try to hold off until the fall. Keep them in their pots and don't water them until the soil is dry.

I don't think you gain anything by planting your container grown natives now, instead of waiting for the winter rains, when they will be acclimated to your native soil during our rainy season. Al

Depends on your drainage and which natives, too. Some are picky, some are not. I think the grasses would be happier in the ground--they won't do much, but their roots will be better protected in the ground than in a pot.

The seminar I attended, the expert claimed native don't like a drip. They like to be watered then dry out, then watered then dry out.

But why can't you water with drip then let them dry out, water with drip then let them dry out? How is the method a problem if the drying out takes place?

I've heard the no-drip-for-natives thing, but never had it really explained. It works okay for me, although I only give them very tiny amounts of water, and only while they're getting established.

If I had to guess, I'd say the real problem is that drip emitters tend to put lots of water all in one place, where natives are adapted to having to gather water from over a wide area, so drip makes it easy (but not inevitable) to overwater part of the root system.

When I water my natives I give em a good soak then let em go completely dry for a while.

I've planted natives in the summer. They've lived but ones planted when it's cooler seem to do better sooner.

Thanks for all the feedback. I'm going ahead with my planting. We're hitting a cooling trend right now so I'm taking advantage of the weather.

Check out this link from Las Pilitas Nursery:

Here is a link that might be useful: When to Plant California Native Plants