Avoid a reputation for being a place of murder! (Priceless)
Visitors pay $5 per plant viewed. MORE will visit the more popular your garden is.
Popularity is based on a COMPLEX FORMULA based on number of healthy plants and amount of fear surrounding your garden.
Fear is increased by recruiting a vampire gardener. Since in this case "recruiting" means biting and murdering someone and condemning them to an eternity as a low-paid vegetarian vampire gardener. Rumors will spread.