Ask Mr. Smarty Plants

There are 9 members of the Fraxinus genus (Ash) native to Texas; we are guessing that you have Fraxinus texensis (Texas ash). This USDA Plant Profile shows it growing in and near Lampasas County.

When you say 2 year old trees, did you mean that it had been planted from a seed 2 years ago, or you purchased a small tree and it has been in your garden 2 years? It sounds to us like transplant shock, either planted in hot weather without adequate watering, or root damage. The sprouts coming up from the base of the tree are growing off the roots of the tree, which means the tree itself is still alive. Since this tree often grows as a multi-trunk tree, we believe you could encourage those sprouts to grow up and be one tree. The "central leader" or the upright trunk that was the original tree may still be alive. Try scratching the bark with your thumbnail, just a little sliver, and see if there is a thin green layer beneath. If there is, we would suggest pruning and trimming back the branches that appear to be dead, but ensure that there are enough green leaves left somewhere, either on the upper branches or the sprouts, to provide adequate nourishment for the tree. Do not fertilize. 

Because the extreme heat of the Texas Summer is now upon it, we don't recommend doing any pruning or trimming except to prevent a dead branch from actually breaking off. Be sure the tree is adequately watered, and wait to see if it will develop multi-trunks, or if the whole tree is just going to die. Ordinarily, we recommend trimming about 1/3 of the upper portion of a tree or shrub in transplant shock, but we are having trouble visualizing how much of an upper part your tree has. If the other ash tree is doing well, are there differences in the locations, water availability and sunlight between the two trees? That might give you a clue to the problem. We would also suggest you mulch the roots of both trees with a good quality shredded bark mulch, to protect the roots from heat, hold water in the soil and, as it decomposes, adding organic matter to the soil to assist in drainage.

From Our Native Plant Image Gallery:

Fraxinus texensis

Fraxinus texensis

Fraxinus texensis

Fraxinus texensis