In the wild the Wollemi grows on sandstone rock with very little top soil. Under reasonably dry conditions the Wollemi after its established simply shuts down and stops growing. I would suggest that you saturate at planting and than water only when the soil is just dry. Ensure that the plant is mulched well. If conditions are very dry I would suggest a good water perhaps once a month. After the tree is established (12 months) it should be able to cope by itself. Wollemi will tolerate 35 degree temperatures. At the nursery in Queensland they record temperatures as high as 45 degree C and as low as minus 5 degree C. I would recommend that you plant the Wollemi in a less exposed position. The branches can be very succulent during high growth periods and these are prone to damage.