Vertical growing, whether upside down (tomatoes) or right side up (the strawberries below) has been a big trend of late. The fact is though, vertical growing has long been a way to make the most of small space. Espalier is a way of pruning fruit trees to have them grow in a flat plane i.e. against a wall and yet still produce abundant fruit. I have recently seen pallet gardens — shipping pallets filled with soil and place vertically — for growing on apartment balconies, too.
This creative idea builds on the concept of the traditional strawberry pot, but allows you to plant as tall as you might wish. This picture I found on Pinterest links to a Flickr set of photos, but it seems pretty clear that they have taken a length of PVC drainage pipe, cut out holes for the plants and then filled it with soil. I could see 3 or 4 of these in a row along a sunny fence. Water is probably added from the top and allowed to flow down each tube.
I have updated the post with this photo and link to a much more detailed walk through of a similar project.
Watch garden videos (and more!) on my YouTube Channel
More information on growing strawberries: