cacti & succulents
If climate change means continuing droughts and infrequent winter rains in the West, cacti and succulents offer a solution beyond all others for designers. They function with considerably less water, primarily because their structures store water, used only when absolutely needed. Many species are considered fire resistant, since they hold considerable water in their systems, so combustion is at a minimum. Specifying cacti and succulents has unique considerations, similar to the needs of many California natives; soil and water need to be treated differently than plants indigenous to places that receive summer rains. Cacti and succulents dislike heavy soils that retain water, so making sure the soils are highly porous is key. For designers, this means specifying soil blends in support of their performance and not relying on standard mixes or amendments. When cacti and succulents are planted in the ground, they prefer intermittent watering schedules, which means changing a watering program to specifically accommodate their needs and making sure they are on their own hydrozone or at least share with the similar needs of other Mediterranean style plants that prefer less summer water.
This all changes when cacti and succulents are planted in containers. The soil mixes and restrictive qualities of pots will likely mean they need more water, and this too will need specific monitoring. Of course, remember that cacti are spiny! Potted or in the ground, they can be challenging to maintain or transplant.