Sharp sunlight

The sun is moving toward its southernmost position (12/21/2014). This south facing terrace is more exposed and is getting spanked by stiff, bright sun which can be withering. Watering every two days absolutely necessary. The bonsai bougainvillea suffer. I thought they'd like their new spartan, root-bound homes. Only so much. I should have used more of the water absorbing polymers when mixing the potting soil-- it's tricky down here using that however, as we have 5-6 months of heavy rain for part of the year during which time, the roots need to dry and breathe. Can't overwater in the cool of winter.. I need to retire and just sit in the garden and do the needful.