Is it really supposed to be the bane of fleas? If so, why? I learned it as Santa Barbara daisy. Is it native there, or was a particular variety of it named for Santa Barbara? Is it a weed? Is it native? Is it a native of somewhere else in California that merely naturalized here? There are so many questions about this simple little flower that is growing wild under a cyclone fence at the backside of a motorcourt at work.
Whether it really is native or not, or whether it is a straight species or a selected variety of one, fleabane happens to do well in drought tolerant landscapes composed of native plants. It naturally spreads out to form shallow but wide mounds. If it gets cut back in its off season, it comes right back. Although it dies after only a few years, lower stems typically form roots and grow into new plants before the original one dies, essentially replacing itself before anyone notices.
If it is a weed, it is polite about it. Stray plants that appear where they are not wanted are easy to get rid of, and do not regenerate too aggressively to be managed. Those that happen to appear in out of the way situation can be left to bloom without much concern of profuse seed dispersion. Weed or not, it is preferred to other nastier weeds that it might prevent from growing simply by occupying the space.
It happens to grow in my planter box downtown. ( https://tonytomeo.wordpress.com/2017/11/04/my-tiny-downtown-garden/ https://tonytomeo.wordpress.com/2018/01/06/six-on-saturday-my-downtown-planter-box-again-and-up-close-this-time/ ) I certainly did not plant it. It was there long before my time, and remain, even if merely in a minor degree, just in case the person who planted it years ago ever stops by to check in on it.