posted 11 years ago
I would think about vines crawling up those "Legs". The water catchment plants on top idea may be difficult or dangerous to maintain. Some have used sedums in eco rooves. There are edible succulents. Access is a key issue. WHere to store the ladder?
Purple passion flower is beautiful, catchy and easy to grow. I live in Portland and may be able to get you some. You are going to have more heat and less cold downtown than in the general area. Palms are catchy but slow growing. They would be ok in a large cement pot that no one would steal. Cactus would certainly be visually interesting, and they are definitely edible. Nopales are usually eaten with eggs or in a salad in Mexico, but I have some in my lacto fermented sauerkraut right now. They do grow here. Careful about planting mix. I suggest gravel. That's what I did.
John S
PDX OR