It works the same as it does in any of the other neighborhoods. Keala Hoapili has the Freelance Botanist aspiration and I've had her grow flowers and tropical plants in the yard. You can splice pineapples to coconut trees, etc., but they just won't produce any fruit for a new species. (You'll still get coconuts and pineapples.) You can find Cowplant berries in the lake in Oasis Springs or get them as a career reward in the Botanist career (or just use cheats to purchase one, which is what I ended up doing). If you have Seasons, the plants will go dormant during the off-season, just like they do in other locations. Keala Hoapili has the Child of the Islands trait, which I think helps her improve the plants faster than if she didn't have it.
You can also just use planters and put them on the deck like I did with the Ngata family. I put the food plants indoors so that they're protected, but the flowers come and go with the various seasons.
https://i.vgy.me/8ckMOZ.png
