Posted: 30/09/2014 at 21:02
Mary - What ever you decide to plant in a pot on your balcony if there are people living below be mindful when watering.
The pot will need to stand in a tray if there are people living below so they don't get showered everyday. Gravel as a mulch in the top of your pot reduces evapouration meaning less watering.
Terracotta pots absorb water so better to use a pot which is unlikly to absorb water...plastic or similar might be better.
I'd be inclined to mix water retaining jelly with the compost if the pot is in full sun, this helps to prevent the compost drying out and the need to water although on hot days you may still need to water daily.
Hope this is helpful, can't help with which tree to plant though...