This is the 10169th most frequent Polish word.
botanicznych
"Botanicznych" means "botanical" in English (related to plants or botany).
Here, 'botanicznych' is used as an adjective in the genitive plural form to describe 'ogrodów' (gardens).
Interesuję się roślinami botanicznych ogrodów.
I am interested in the plants of botanical gardens.
In this sentence, 'botanicznych' serves as an adjective describing 'tematach' (topics) in plural, indicating the subject of botanical studies.
Książkę o tematach botanicznych znalazłem w bibliotece.
I found a book on botanical topics in the library.
Here, 'botanicznych' is used as an adjective modifying 'motywach' (motifs) in plural form, referring to artistic styles inspired by botany.