The root ball on the one in the middle, the brown one, may have dried out or almost dried out. Can't tell if this happened past the point of no return.I have one that almost bit the dust too several years ago.

If you insert a finger into the soil near the crown and it appears to be dry, you may need to extract it and dump it in a pail of water to see if comes back. Leave it in water for about an hour until there are no more air bubbles. Alternatively, you can set a soaker hose to drip water slowly, very very very incredibly slowly as dried out root balls do not absorb water easily so hand watering does not help. Again, do not hand water it with a hose. Just let the hose drip... one drip every minute or every 30 seconds. Like a drip irrigation system. The plant may not leaf out again until Spring. I had one that did not leaf out when the temps went down in the summer but it sprung back in April instead.

Or you can replace it.

To make sure this does not happen again, use the finger method daily for 2-3 weeks. Insert a finger into the soil to a depth of 4" early in the morning. If the soil feels dry or almost dry, water the soil -about 1 gallon of water (1.5 gallons in the summer). Anytime that you water, make a note in a wall calendar. After 3 weeks, review the information on the wall calendar and determine how often you were watering: every 3 days? every 4 days? etc. Then set the sprinkler to water 1 g.5 gallon on the same frequency (every 2/3/etc days). If the temperatures change more than 10-15 degrees and stay there. use the finger method again to see if you need to tweak things.

Maintain 3-4" of organic mulch to conserve soil moisture and make the waterings last longer.

Thank you very much for the reply. This must be what happened. Also explains why we've hand watered this plant 2x in the past week and it didn't seem to be perking up. :-(

With the drought, there's probably very little ground water...so I've got to monitor the need for water a lot better. Appreciate the explanation.