Water conservation is the goal with xeriscaping, so avoid over-watering at all costs. Soaker hoses and drip-irrigation systems offer the easiest and most efficient watering for xeriscapes because they deliver water directly to the base of the plant. This reduces moisture loss from evaporation. They also deliver the water at a slow rate which encourages root absorption and reduces pooling and erosion. In general, it's best to water deeply and less frequently.
If you haven't got the ability to use drip-irrigation systems, just lay your hose on the ground at the base of the plant, and turn the hose barely on. In other words create your won "trickle" system! Allow it to stay there for 10-15 minutes per plant. Remember, the water should BARELY be running. You want it to soak in without running off at all. This will take some running back and forth to the garden, but once the plants are established, you shouldn't need to do this but a couple of times during the summer and only at the DRIEST times.
My garden is strictly "on it's own". It's too far from a hose to even do this, so if the plants don't survive, I've learned something. I won't buy that kind of plant again.
When I plant, I water deeply and carefully. With the mulch on nice and thick, the plants should be absolutely fine.