I'd like to think it's not a trend but I have a feeling it is.
With a recession on many Americans are not focused on oranamental flower gardening or renovating their yards for ornamental reasons. A trend is on for local food and the locavore movement as well as a wee bit of the idea of growing your own edibles in order to save money due to the recession or personal financial issues with families.
In Cleveland the Botanical Garden had trouble getting sponsors for their biennial flower show so they turned their efforts into edible gardening of local foods. This sparked an interest.
Here is the story from The New York Times: Botanical Gardens Are Turning Away From Flowers.
I am sorry if I appear pessimistic about this, but I'm a realist. I had an edible garden in 1996, the first full growing season after owning my own land that I could do what I wanted with. I grew edibles as they were superior in taste and quality to what could be bought at the store or even from local farmers. I did this before it was a trend when people thought I was weird for spending my time that way. I composted and did other green things and my friends and family thought I was nuts. I also had flower gardens and enjoyed that, back in the mid-1990s that was the trend. Around here the flower gardening has waned, less plants are available at local nurseries, some nurseries have gone out of business, and many flower gardens I see around have gone to weeds or have been planted over with grass seed.
Now all this is locavore, eating local and growing your own edible foods is "in" but I'm skeptical. It takes a lot of work to keep even a small edible garden. Results are inconsistent. Stuff happens: mildew, bacteria, bugs, squirrels, woodchucks, rabbits and deer wreck the crop for human consumption. This is discouraging. Only the most persistent gardeners keep this up year after year, putting money, time and sweat into their gardens for uneven results. This is not in the character of most Americans today. It was the way of my grandparent's generation but it is not the mindset of the Baby Boomers, most of whom love their grocery stores and still praise processed, easy, fast cheap foods. It's definatly not the way of my generation, Generation X, most of whom can barely cook let alone want to spend their time growing vegetables.
I'm a gardener. I'm a realist. And that's my two cents on that.