Well, I’ve known a Ruby, a Pearl, a couple of Summers, and a couple of Autumns. But as a percentage of the people I know, those are still fairly rare names.
True. Interestingly enough, Ruby has become quite popular in certain parts of the English-speaking world. (Top 5 in a lot of Australia) and even “Sienna,” “Grace,” “Lily,” and “Summer” makes a Top 10 appearance in the Gold Coast region of that country. (“Lily” and “Ruby” being number 1 & 2 female names for all of Australia in 2010.)
Now that I think of it, Ella is also a name of a tree - specifically, the pistacia palaestina. It’s very common in Israel, most famously in the Valley of Elah, where David fought Goliath.