Jsc,
Only water once a week and stop fertilizing them.
You are killing them.
Leave them alone.
If it rains, do not water.
Leave them be.

Yes, stop with the fertilizer.

Check the moisture of the original rootball of the failing tree. It's either soaked or dry. Stick your finger in it to determine which. If dry, drizzle water directly onto the rootball.

CrApe myrtles are drought-tolerant plants. The only way they'd need to be watered every day is if they were newly planted in pure sand. Longer (deeper), less frequent watering is much better than shorter (quick), frequent watering. Use your finger and poke it down two to three inches into the soil to gauge soil moisture. If you planted an intact rootball, check inside the rootball as well as in the surrounding soil (different soil textures can result in different drainage characteristics). The soil's surface should be allowed to begin drying in between waterings.

Here is a link that might be useful: Planting a Tree or Shrub - see section 12

Thanks so much! I'll do that.

and never forget.. they are not children.. they do not need to be fed ..... they may never.. ever.. need to be fert'd again ...

especially if they are planted in a lawn that is fertilized ...

if you think something is missing from the soil .. have a soil test done.. and act accordingly ...

ken

We have clay soil, so I don't know if that's affecting the crepe either. I'm not sure how adaptable they are in different soils.

Crape myrtles do fine in clay soil. Clay is the norm around here and crape myrtles are everywhere.

Drought-tolerant trees tolerate drought *only* after they establish a sturdy root system in their planting site.
In general, that can require1 or 2 years of regular irrigation as the gardener works toward a "normal" irrigation schedule for that particular kind of plant

In the several months following planting, the roots of drought-tolerant trees are gradually extending outward from the root ball.

So early on, the key is to water the rootball more often than the surrounding soil. (Butt that assumes the planting hole was filled with water and allowed to drain - twice -- before the tree was set in place.)

Crape myrtles are fast growers. Only a very very large one with a relatively small rootball at transplant would need two years of supplemental watering. Even a newly planted one shouldn't need daily watering, and would be likely to suffer because of it.