Indoor Aquariums perhaps? where you can breed clams, crayfish or fish. they are not really plants, but would fit in the scenario of plant terrariums. Of course you could try to use an aquarium for a certain kind of seaweed if it really has to be plants.
In combination of the beastmaster, maybe an outdoor garden that has certain pets in it, like a durni garden. where you can harvest meat. THese durnis cannot be taken out to start beastmastering it, but maybe certain species can breed eggs in captivity. either for hatching or prcessed as resource.
Here is an crazy idea, a special kind of seed that can be launched from a special weapon that snares enemies as when the seed is shot from the launcher it will pop in some nasty vines. (Maybe a bit too crazy)
Flowers and plants can be used for unique paint and texture kits for either clothes, but also armor and furniture.
Here are some extra questions:
Will there be special garden lots? or must we use the current lots we got? if it uses a lot, then consider to put up a small crate or shed onto the garden to compensate for the loss in storage for some people.
Will gardens be tied to cities or can i transform tatooine in the garden planet?
Will gardens be tied to houses, does a garden need to be close to my home?
Will there be a special house deed that has a garden attached to it (i'm thinking of on of the paintings of a residential house where there is some sort of vegetation on the second floor)?
Good work keep it coming