I have a new Eucalyptus tree for which I prepared the hole properly and added mulch, etc. I have babied it, watering regularly, however, about a week ago the leaves on the lower branches started drying up, not yellowing first, just becoming brittle. Day before yesterday, it was only a few bottom branches, and my son, whose visiting, decided that it needed more water. In one day, all the leaves on the whole tree have dried up, despite very moist soil. I Dug the tree up and the roots had already started to reach down into the soil and the soil was damp and l loose. The small branches still seem to be alive. My son put a heavy drip from the hose on it about a week ago and then again 3 days ago, in addition to regular watering. Could this problem be caused by overwatering?