Strange thing, but my money trees HAVE counted towards the gardener career. In fact, I managed to get from level 9 to 10 exclusively on money bags. Is this just an awesome glitch? As far as other harvestables, I think Life Fruit sells for the highest. It sells for $100 at perfect quality. But you don't need an omni plant for it, so that's kind of useless. I usually use omni plants for fertilizer. Feed it some sort of excellent or higher fish, and then when you harvest it and fertilize a plant with it, you're almost guaranteed a perfect harvest from that. I like to sell my Life Fruit instead of using it as fertilizer, so the omni plant fish is a good alternative for me.