First, I applaud you on deciding to xeriscape.

>>What do I have to consider as far as my soil's ph goes? I hear some people say it's important, and others just seem to plant what they want. Do I pick the sort of plants I like then make sure my soil ph is compatible?

It's usually easier to do the opposite. Determine your soil pH (please use a good laboratory as hand-held testers and home testers are notoriously inaccurate). Once you know that, choose plants that are compatible with your soil.

You can push it a little bit, but it's generally easiest to make certain that the plant you use is appropriate for your pH. Restricting this immediately stops you from falling in love with a plant (like, say, a rhododendron) that absolutely won't perform or look good--or even survive--at your pH.

>>I also have some nice palm and pomegranite trees around my house. I don't wan them to be adversley affected if I had to change my soil's ph.

Within some limits, I wouldn't change the soil pH, I'd choose compatible plants.

>>Also I want to use decomposed granite as a ground cover. Forgive me for asking what may seem a silly question. But I plant and root the plants in the actual soil right, not the DG?

In the actual soil.

>>Also when roto-tilling out my grass how to I assure I don't destroy my sprinkler system?

You're going to need to know exactly where your lines are, and how deep. While we don't generally recommend roto-tilling, I accept this one as an exception to that rule. :-)

>>Should I compact the DG or is that bad for the plants?

I have no idea, sorry. DG isn't something we use around here; mulches are generally hardwood. I'd listen to anybody else's recommendations for or against DG over mine as I have no familiarity with it at all.

>>-Starve my current lawn of water until it dies. 4-6 weeks?

4 to 6 weeks is survivable by most grasses. Ten to twelve is less survivable. The tilling will destroy most of the root mass, however, so even the four to six should be OK.

I'd still consider spraying down the lawn with Round Up to kill it while it's green, however. That's inexpensive, fast, and reliable.

Some grass will somehow manage to survive and re-sprout in your wet season (grass really is durable stuff). It'll even come back through four inches of mulch, although that will make it even more rare. Plan on needing to weed out some here and there.

>>- put in weed blankets

Generally not recommended. Weed blankets work, sort of, but starve the soil below them of oxygen and bacterial/fungal action (which is critical for the plants as they have tons of symbiotes). If you do use them, cut extremely wide areas for each plant, not just a little slash in the thing to get the plant in.

>>-shovel in 4 inches of DG
>>- replace sprinkler heads with drip irrigation

I think you're going to find it easier to put in the plants (with large holes in the blankets if you use them, as absolute minimum as big as the plant will get at maturity), replace the heads, and THEN put in in the DG.

It takes a lot longer, but you get to set everything up properly before burying it under stone.

Cool thanks that was really helpful. Anyone out there know how to go about compacting the soil?