Watering a tree can be a bit of a pain if you have not been able to install a drip watering system. When we put these trees in, we knew they would need water every day during our hot summer weather, but we wanted to make sure that water wasn’t simply poured around the base to evaporate from the soil without reaching the roots.
This was a bit of a tricky one, but my current solution is very low tech – I rescued a few PET bottles from the recycling, filled them with water and upended them into the soil near the base of the trunk. The water feeds out of the bottle relatively slowly (takes more than half an hour) and the water is reaching a level below the surface of the soil where it was more likely to evaporate than penetrate deeper into the soil.
If you wanted it to drip out even slower, you could drill a hole through the cap and do the same thing. It would filter out even more slowly. That is what I am likely to do if we have to go away at any time.
Of course, if I get to a point where I can install a drip filter watering system, I will, but in the meantime, this seems to work just fine.