Hi, I recently picked up a bunch of old redwood fence boards that I'd like to make into vertical planter boxes about 4' tall with interior dimensions of 5"x5" for a narrow strip of the yard that gets 4-5 hours of sun a day. Ideally whatever is planted will grow fairly tall, maybe 1'-3', the higher the better, though maybe due to the size of the boxes this is unrealistic. I'm in Northern CA zone 9b. Any suggestions? Thanks!