There is no difference between the trial version and the "real" version, except that you don't have access to all of the game features in the trial version. The game works a lot like a real nursery would work - you pollinate different plants to get seeds (which you need to keep track of). You then grow plants from those seeds and use those plants to make new hybrids. There is no facility in the game for naming plants, so you'll need to come up with a way to keep track of what you're doing, if you want to be organized about your breeding program. I've found all the magic plants by random breeding, but you will never discover all of the different plants by random breeding - there are just too many!
Someone has developed a MobileDB database that is available by request. Here is a
link to the post that contains the information.
The easiest way to water plants is to grab the watering can and "drag" it across all of your pots until you see the water meter fill up for each plant. That works well on both the Palm and PPC version of the game.