Game type: Browser-based.. um... time-waster game.
Time demand: Not much. The sort of game you play basically as long as you want, though you'd probably need to invest a little time at least to get any interesting growth.
What it is: You start off with a fairly simple pink flower, and click on it to grow a new copy. As you grow each flower, slight mutations may start to occur. You can click and drag to clone a flower, and click and drag to another flower to create a seed between those two types. Basically, you get to play plant-geneticist on a browser-based game. You can also see the "genetics" of a flower you particularly like, or grow flowers from genes others share with you.
So, yeah. Really simplistic in a sense, but it can be an addictive little time-waster if you're in the mood for it.