horticulturist (n.)

1670s, "cultivation of a garden," coined from Latin hortus "garden" (from PIE root *gher- (1) "to grasp, enclose"), probably on model of agriculture. Famously punned upon by Dorothy Parker.

word-forming element meaning "one who does or makes," also used to indicate adherence to a certain doctrine or custom, from French -iste and directly from Latin -ista (source also of Spanish, Portuguese, Italian -ista), from Greek agent-noun ending -istes, which is from -is-, ending of the stem of verbs in -izein, + agential suffix -tes.

Variant -ister (as in chorister, barrister) is from Old French -istre, on false analogy of ministre. Variant -ista is from Spanish, popularized in American English 1970s by names of Latin-American revolutionary movements.