Sadly he nowadays seems to be a bit forgotten, apart from the Napolitan ice cream here in Germany named after him (chocolate + strawberry + vanilla), and I am not aware of any books on him in English.

He wrote many books, by which sale he got revenue to foster his expensive landscaping. The "most famous" is probably "Tutti Frutti", which is not about landscaping but a ironic representation of his current times – but this as well has not seen any reprint for probably a century now. I always wondered, why... Maybe I'll do a reprint someday :)