Many plants will set seed in the bountiful waterwise garden. Lavender dentata often sets seedlings around the garden and salvia chameadryoides spreads by underground runners and seeds.  These plants can be transplanted to appropriate areas or potted up for friends, or a plant swap. Succulents also pup readily and are very useful for colonizing bare ground while other plants become established. The succulents can be removed later, rather easily as most of them are shallow rooted.  However, some agaves, such as the giant Americana, put out offsets very close to the mother plant making them difficult to remove and therefore invasive. Aloes make much better colonizing plants as the thorns are blunter and they flower at least once a year.