As to close or far planting I agree it is a big question for Med gardeners. My first inspiration is what hapens naturally in such climates, particularly my own. Permanent tree and shrubs are very far apart with far reaching surface root systems. in between grow a lont of annuals, corms, tubers, bulbs and a few tough perennials which do not feature year round but are seasonal and often quite dense over the surface. So this is what I try to immitate, even if in a somewhat crowded way. In other places there is an understorey of low/ prostrate shrubs. In this type of bush the plants spread out over the surface just as the roots do underground, thus achieving a density of cover without having a dense planting. There is another kind of system too; this is where the soil surface is covered with a layer of small rocks, stones, pebbles, coarse gravels etc making a kind of pavement through which bulbs etc grow in their season. I find this hard to emulate as we cannot get river-rounded stones and pebbles, only crushed rock from a quarry which is too un-natural looking and too rough to walk on o/wise I would love to have a gravel garden.
Aloes are often found in association with dense bulb colonies, grasses and very low succulent populations. There is a hint about how to grow them in your garden.
Agaves are often found in tall dry annual grasses and very open shrubby bushes. Another hint.
Mny small succulents HATE being in full sun all day and prefer the light shade cover given by grasses and small open bushes or in rocky slopes where drainage is excellent and shelter present too.
