A gardener needs a purpose. A plan.
Without one, it's not really gardening at all. All the random digging and planting in the world will amount to, at most, landscaping.
Gardening in Shu's Garden is a fun experience set in a beautiful fantasy world. A lack of purpose, though, means that it's difficult to call it a game.
Really, Shu's Garden is a virtual gardening toy. It grants you control over Shu, a circular, furry blob of happiness.
Tilt your iPhone or iPad and Shu will roll through a lush, undulating landscape that eventually loops back on itself. As she rolls, plantation will spring into life underneath her.
Hold the screen and Shu will start shrinking, coiling herself ready to spring into the air when you release your grip. This comes in handy for reaching the glowing seeds that you'll find dotted around this compact world, up trees, in ruined mountain monuments, at the bottom of lakes.
Roll into these and they'll stick in Shu's hair. Now, when you shake your device, a gathered seed will be released and planted wherever it falls.
Shu's Garden runs on an accelerated day / night cycle, so returning to these seeds a little while later will reveal a colourful new plant.
Touch the picture of Shu in the bottom-left-hand corner, and she'll suck up any plants in her vicinity, allowing you to indulge in a spot of pruning.
To say 'that's it' would be a little harsh on this lovingly crafted timewaster. Essentially, though, that is all there is to Shu's Garden. There are no objectives, no levels, no adversity, and no rules. Just move, collect, plant, and observe.
As well as being a beautiful world, it's a fairly tactile one. There are a couple of creatures and bodies of water with which you can interact - I had particular fun launching a turtle up out of a small lake.
But most adult minds will soon find themselves tiring of Shu's Garden.
Really, Shu's Garden is only likely to be of sustained interest to very young gamers who find simple movement; colour; and cause and effect endlessly fascinating. Indeed, it's explicitly aimed at such gamers.
But it still feels like this is something of a demo, a tester for a much more involved and ambitious project with a proper purpose.