Since I´ve previously posted some comments on Plantasia and Cultivation, here´s a list of gardening/flower-themed games I´ve found (most of them, today - which shows I might not researched competitors properly :)). Plus, some comments on how they relate or not to my own project.
Cultivation (experimental game)
What I like the most about Cultivation is how it uses procedurality (is that a word?) to create new plants. The social aspects are great too - but that's something I haven't planned at all for my game. They share the 'genetic thematic', though.
Plantasia (web / casual game)
Plantasia is more like a management game. Fun to play, good use of flower theme, but much more managerial than Flora. It made me think of including pests and bugs - which I didn't do. The game point of view is somewhat similar to Flora.
Enchanted Gardens (casual game).
Haven't played this one. Judging from the screenshots, seems to be a matching tile game.
Plant Tycoon (Pocket PC).
Also haven't played this one, but it sure looks interesting: It´s a gardening sim (tycoon-esque, as far as I could tell), but also invests in genetic manipulation, as flowers can be cross-pollinated.
Blooming Garden (webgame).
"Align rows of five" kind of game.
BBC Virtual Garden (not a game)
Non-game(?) for players to exercise their paisagistic abilities. Interesting. As in Flora, it tries to be a relaxing experience.
3D Garden Composer(gardening sim/encyclopedia - includes a game).
Much more of a learning tool (making use of games to do so) than the other titles on the list.
Flower Shop (casual game)
A sim/management, "keep customers happy" type of game, as far as I could tell. Looks very well done - great production value.
Cbeebies Gardening Webgame.
Using the arrow keys, make the character water the flowers.
US governamental/educational gardening webgame.
Very similar to Cbeebies. Using the arrow keys, make the character water the flowers.
Zen Puzzle Garden (casual game)
Not really on gardening, but I really liked this puzzle game. Zen gardens reminds me of my previous project, Insular.
Plant Maker (web activity).
Like in Flora, you can make your own flowers in this web activity. There are not too many possible combinations, though - just 4 options for each category (below ground, stem, leaves and flower).
Maggie the Gardener 2 (casual game).
Focused on garden decoration, another very well polished gardening game.
The Flower Garden Game (webgame).
Geffrye Museum Design a Garden (web activity).
Simplified garden design.
Garden with Insight (garden simulation).
Free garden simulator. This one is probably the more complex of them all - it looks very accurate. It can be used as a educational tool.
PlantStudio (2D/3D plant illustration tool)
From the same company that makes Garden with Insight, this is an illustrations tool where you can design your own flowers. Looks very interesting too.
Well, that´s it for now. You can expect more news on Flora any day!