In order to explore the value of gamification you need to have two things close to heart. (1) Gamification does not work without content AND (2) to have accurate and up to date content you need incentives i. e. gamification.
(1) Gamification need content
It's quite obvious, but there are some services using just gamification as such, meaning it is just a game. Early versions of check-in services used gamification beacuse they could. You could check-in on different places, earning badges and reputation along the way and have a weekly highscore list to look at and strive for the top - but there are no content. I'm here and you are there, that's it. It will be boring and only new users will use this kind of service without content. You need content to get gamification to work.
(2) Incentives drive users to keep content accurate and up to date
When we understand that we need content, we should also know that this content need to be accurate in order to have visitors. We have all visited sites with very good content when it was written, but then left unattended for several years making it old and not that useful anymore. To deal with that we need to have users who are willing to update and moderate the content making it useful for visitors. Those gate keepers and key masters need to have incentives in order to continue moderation of the core value of the site. That incentive can be a salary to employees OR reputation and badges in the context of gamification.
In your case for flower enthusiasts it is unlikely that you're sponsor are willing to hire personnel to do the job, at least in the beginning of this project (I'm guessing, but between the lines of your question this is what I interpret). Then you need to gather users who are willing to spend time on your site moderating content - and that's where gamification comes in. Use it wisely, and it has a potential to be successful.