Brittlebush Side by Side

Arizona desert plant life is amazing.  For many species, much of its life cycle (leafing out, dropping leaves, flowering, etc) is dependent more on recent rain than on the season or even the temperature.  For example, ocotillo are famous for producing a whole lot of leaves nearly overnight and then dropping them whenever conditions change.  On a single hike you can see ocotillo in all different states of leafiness or nakedness.

Brittlebush (aka brittlebrush) is another one that can look dead in dry spells and then, when temperature and water conditions are right, will suddenly send up shoots and burst into a riot of yellow flowers.  It's more dependent on season than ocotillo, but individual plants vary so widely as to when (or if) they bloom that you can mistake them for different species entirely.

Here's a drastic example.  These two brittlebush plants were next to each other, maybe a foot or two separating their edges.  But one must have had access to better water runoff or something.  Look at the difference:

Pictures taken April 14, 2018 at Peoria Westwing Mountain Preserve