Low maintenance is rarely about fewer plants. It is about the right plant in the right place, and never leaving bare soil.
Plant for the site
A plant suited to its position largely looks after itself. One fighting the wrong soil or the wrong light needs watering, feeding and eventually replacing.
Cover the ground
Bare soil becomes weeds. Ground-cover perennials or a layer of bark stop seed germinating and hold moisture, so you water less often.
Put irrigation on drip line with a timer. It delivers water at the root rather than on the leaves, and keeps working the week you are away.
