Our concrete front yard was supposed to be converted into a garden but the plan did not materialize. Nevertheless we still call it garden even if it remains concrete. I think it is better that way for a concrete garden is easier to clean than a grassy lawn. Besides there is no needed weeding so the maintenance work is lessened.
Since the garden is the toilet of our dogs so we have to make it clean from time to time. Cleaning the garden is not only by water. We use liquid soap that we mix with a bucket of water to apply on the concrete. Leaving the soap overnight cleanses the garden very well. Rinsing is easy too.
Do you clean your yard regularly?