Ohio is the Buckeye State. The Ohio buckeye that is native there must be very special. Perhaps all other trees that are native to Ohio are just not very uninteresting. Whatever the situation, I sort of believe that the Ohio buckeye is more appealing in some regards than the California buckeye that is native here. However, the California buckeye might be more weirdly interesting.
The main reason that California buckeye is not popularly used in landscapes is that it is ‘twice deciduous’. That means exactly what it sounds like. Just like other deciduous trees, it defoliates in response to cooling autumn weather, and refoliates in response to warming spring weather. Unlike other deciduous trees, it repeats the process through the warmest weather of summer.
When summer weather gets too warm and arid, the foliage of California buckeye shrivels and sort of defoliates. Without rain to dislodge the shedding foliage, it can linger and look shabby for quite a while and maybe until it is replaced by secondary foliage that develops as the weather mellows. The secondary foliage does not last long before it is time to defoliate again for autumn!
California buckeye is not often planted into landscapes because it really does look like the living dead through summer. It provides no shade when shade is most desirable. Those that I work with are only here in the landscapes because they grew from self sown seed that sneaked in on its own. Some will be subordinated to more desirable adjacent trees, although there is no rush.
I happen to like California buckeye. Except for the rarely seen red horsechestnut, it is the only species of buckeye that I am familiar with. Bloom is neither colorful nor reliably profuse, but is delightfully fragrant in close proximity. Not many natives are fragrant.