for making the game a more valuable subgame inside your (rpg like) page,i´d turn it into a quest game,give an objective and a story.
quite simple to achieve actually,let´s say the ninja girls grandma has birthday soon,ninja girl thinks about some flowers would be a good present,so she starts to plant some nice flowers (already implemented in your game),the flowers grow nicely and right on the day of grandma´s birthday,suddenly dwarfish cyclops enter the garden to steal the beautiful plants.you have a timer of one minute,the cyclops always try to get close to the plants,each time they are over one of them,the flower dies a little.
once all are gone,you loose.if you rescue some of the flowers,you win.
then you can bring them to your grandma and get something for it (like a new ninja sword,as your grandma is also a ninja,of course).
still,you have to watch out while bringing her the flowers,as the big bad wolf awaits on the way,but that´s a different story..
hm,you see,i´m bored..
will go work on major phreax some more..