One of the design features I noticed while in Spain this summer were the number of apartments featuring lots of greeneries on the balconies. The one above was taken from the taxi while getting to our hotel in Barcelona.
In Ibiza, there was a really neat apartment building called Las Boas (designed by Jean Novel) with very colorful greenery on each floor. The way they added color was very clever. Most of the plants are green but the mesh around the plants vary in color and create a very interesting effect, almost as if someone decided to color the balconies with giant markers. This wins the most colourful display of greenery I've seen on a building thus far. I couldn't help but draw it while I was there.
Patio Blanco (also designed by Jean Novel) use a more minimal approach with purple flowers against white walls. I assume the "lines" on the walls were installed to guide their growth, just like the one on the fence in front. It's neat to see that they actually plan the look of the building in the years to come. It will be covered with natural graffitis. If I get a chance to go back, I'll definitely check it out to see how it has changed.