As often as they need it. Get a moisture meter and use it. Whenever the soil reads half-dry, thoroughly soak the plant again. This lets them get a good start. After the summer, taper off the watering, but decrease the frequency, not the quantity (water less often, when you water, soak the plants).

I always water "low-water" pkants twice a week through their first summer (no natter when you planted them), unless they are clearly growing fast. Even then, I soak them once a week for the first summer. The second summer - every other week, unless the summer is a real hot one.

I bought the moisture meter. Very useful.

Thanks!