Someone Who Grows Cannabis Practices:

Horticulture? Agriculture? Botany?

he should pratice caution, concealment, and little trust

Cannibalism?

Cannabis culture.

Until they get it right.

A felony?

Can call me when he’s mastered it.

Agriculture: The science of raising food crops and animals for farming
Horticulture: The science of cultivating flowers, herbs, orchards, gardens.
Botany: The study of plant biology, anatomy, physiology, and taxonomy)

By virtue of the fact that they’re growing, it isn’t botany. So by definition they are practicing horticulture. Though you could make an argument that once it scales out to a farm-sized operation, then it becomes agriculture. For example, tobacco cultivation is generally classified as agriculture.