How much miracle gro and tree stakes did you give them? How about water?

I don't use miracle gro. All 3 trees still have two tall and thick stakes put in at time of planting two years ago. All 3 trees get equal amount of weekly watering through pcv tube down to roots. But only one is well. Last year all 3 flowered and were in good health. I wonder if this past winter drought and north-western winds might have done them in. Do you think the roots may still be alive and maybe will heal by next year?

I would check the soil before you water them again, and only water the 2 poorly ones if the soil is dry down 2-3" - with fewer leaves, they will most likely be using less water - no point in drowning them on top of their other problems. It may well have been the winter's drought and winds that caused the present problem - even though they are all 3 planted in "one place", the good one may be a bit more sheltered than the other 2, either from other plants in your garden or from buildings - even a small change can create a different microclimate.

If you have them planted in your lawn, or a flower bed, and fed the lawn or bed with a high N fertilizer, or with a weed-and-feed type of lawn product in the spring, that may also be a factor - either too much fertilizer, burning the roots, or the weed-and-feed burning the roots, or too much N. As well, if you, or a neighbor, sprayed Round Up, or another herbicide on a windy day, there may have been some drift onto the 2 poorly trees. They SHOULD, if it was minor, be fine next year.

If you haven't mulched them, I would, for all 3 - as widely as you can, no deeper than 4", and no mulch in the 2-3" next to the trunks. As long as you aren't overwatering, nor underwatering, and as long as the cambium layer (just under the bark) is still green if you lightly scratch at a twig or branch, then I wouldn't worry too much about next year, until next year gets here....

Thank you dibbit. I think your suggestion that the tree might be a bit more sheltered is right on, because even though they all face west the good one is between the two burnt ones. I have removed the lawn that surrounded the trees and am in the process of replacing it with drought resistant plants. Perhaps the incredible amount of dust raised by the guys as they removed the lawn didn't help either.
I just returned from a 5 days trip and now I notice white powder on the top leaves of the "good" tree!!
Any suggestions? I heard that soap and vinegar and water solution treats mildew on trees, ever heard of this treatment?
I had no idea that this beautiful tree would require such high maintenance...

Crape myrtles are typically nearly zero maintenance.

Did the landscaping company use any kind of herbicide when they got rid of the lawn?

If your crapes are not one of the named hybrids, then they are not likely to have the genetic powdery mildew resistance. Plants that are labeled simply 'pink crape myrtle', for example. Is this your situation? Anyway, try rinsing your tree in plain water. Powdery mildew is one of the few fungal diseases that does not propagate in water, and can actually be rinsed away if you do it regularly. It will not 'cure' leaves that are already infected into the cells, but can prevent the spread of the disease.

I wonder if your watering technique is missing the root system entirely. Tree roots tend to be quite shallow. New roots that develop from those that are newly planted grow laterally from the upper few inches of root mass. If you are targeting the watering any deeper than about 6 inches, you're missing the predominance of roots.

Thank you rhizo, the tube we installed 2 yrs ago at planting time directs water to the bottom of trees. However, I also water the surface because I plant annuals around the trees. The landscaping workers did not use any herbicide, they just dug out the very deep rooted grass. I'll try and spray water on the leaves.
Thank you again!

The order for crape myrtles is benign neglect. They do not appreciate excessive water or fertilizer. I leave mine totally alone and they are all in full bloom at the height of heat in Texas. If you are having problems with powdery mildew, put two tablespoons of backing soda in a gallon of water in a pump-up sprayer and spray the entire plant. Again, crapes do not appreciate too much water. You mention deep watering. What about the drainage. Turn off the water.

I think the "tube to get water to the roots" was a mistake. They did the same thing locally at the community college on advice of the contract landscaper -- lots of dead trees with 2 to 4 years.

I suggest you abandon the tube and instead water from the "top" and allow the water to soak into the ground.

Build a dike just outside what would (should?) be the rootball, then fill it 3 successive times at an individual watering (hope that makes sense).

I'd also test to see if the trees are rooted in.

To do so, grasp the trunk at about 3 feet from the ground -- in other words, bend your elbow at a right angle, then grasp the trunk. (Phew; this is easier when I talk to someone face-to-face!)

Next, rock the trunk back and forth while watching the soil at the base of the tree. If the soil moves, the tree didn't root in.

So that's also a guide for your watering dike. Make a dike at the edge of that wobbly rootball and a 2nd one a foot or so beyond it. Water within both dikes -- as said above, filling it at least 3 times.

Later -- perhaps an hour or more -- stick a trowel into the ground. How deep did the water go? If not sufficiently deep, add more water.

The soil between the two rings will remain moist for a long time because roots aren't there yet. The inner ring will need to be watered more often because the roots are there!

To know for certain when to water again, check the soil with a finger or trowel.

I will emphasize it again, do no over-water crapes. They do not like wet feet. There are crapes all over Texas in full bloom in triple digit weather. We leave them alone. The only water mine get are from the sprinkler system run twice a week. Pull out the PVC tubing.

What about the annuals planted at the base of the trees? Any chance you are damaging the surface roots when planting these?

And, although crapes don't like to be over-watered, they DO need water when they're young, before they've developed strong root systems. Just not too much, you've got to let the soil near the surface dry out between waterings - the annuals, unless they're very drought tolerant, would not like this regime, as their roots are even more shallow than the crapes'.

Thank you, everyone. I will pull out the tubes. I think they will all survive and we are putting in a low-water garden so they will be watered regularly next year but not excessively. One question: what about the stakes? I get a daily onshore breeze from the ocean (the ocean is a couple of miles away so no problem with salt) but we get a moderate wind every afternoon. When should the stakes be taken off? I'm concerned if we leave them on too long, they will not let the trunk strengthen.