There were two big things that bothered me about the story. The first, that has been already mentioned by several people, is bad social psychology. I can believe a trend of body modifications that involves trees being grafted to human bodies. But I can't believe that the driving force behind it is a universal rejection of advertisements. Not only for reasons like the fact that never in the history of mankind did one form of advertising replace another, but rather they just add up incrementally. And no democratic government would outlaw an existing business model - putting thousands of advertising agents, printers, graphic designers, etc. out of work - because a vocal minority thinks they have a better solution. But there's a far simpler reason - people like advertising. Not all the people, and not all the time, but advertising is designed to appeal to people, and in aggragate, it is succeeds.
The second reason is - bad botany. Occicat mentioned the smell of Durian trees, a detail that the story conveniently forgets. But the story starts with bananas - bananas don't grow on trees. They grow on tree-sized herbs. There are some crucial distinctions - one of them is that each banana "tree" only flowers once and only produces one set of fruit. After that, it will start producing shoots that will grow into other banana "trees", and the main stem eventually dies. If it's smaller, it will go through it's life cycle quicker.
For a story about people and plants, it is a rather big problem that neither people nor plants acted in a way that seemed vaguely realistic to me. That left the third main theme in the story, sex. Which, unlike people and plants, the story seemed to understand quite well. But I personally have a pretty negative reaction to body modification - I find it extremely unsexy. And one theme in SF/horror I find really terrifying human-plant hybrids (the 1970s Invasion of the Body Snatchers scarred me for life when I was very young). So I found the sex scenes disturbing rather than erotic or appealing.
Overall, then, not a story I enjoyed, at all.