I asked this question about my potted lilly pillys. I have another separate question.
I live in a temperate climate zone. I have plants on a east facing balcony- they get sun from about sunrise till the middle of the day.
I have Syzygium smithii, lilly pillys native to Australia, planted in square concrete planters. They are approx 2.5 foot wide and deep, and 2.5 foot tall.
They are unpainted (I had wanted to paint them before they were planted and was talked out of it).. they dry out very quickly.
Would painting the outside help conserve water, and if, so would an oil based paint be the best?
Would it have been better to paint them on the inside?
What sort of material is good to retain water, ie terracotta, concrete?