A very warm fall followed by a sharp freeze with no typical gradual cool down period affected a lot of deciduous plants in the New England area. The cold just hit before the plant could complete leaf abcission. Provided the plant was sufficiently established to weather the winter cold (and if planted in spring it should be), it should bud up and leaf out at the appropriate time. The old leaves will fall off when the new buds emerge.

It's not dead. It probably looks like every Crape Myrtle in the Middle Atlantic and Southeast! They did not lose their leaves normally in the Northeast last Fall due to excessive HEAT. Then, there was sudden hard frost (forget now if it was early Nov or Dec.), but the same delayed leaf drop was seen on Japanese Maples. I am also in NJ/Zone 7 and have no concern over my collection (yes, they are addicting!!). LOL.

P.S., They leaf out relatively late in the season, depending on the weather, but buds should be swelling by April or May.

I agree. It was due to that sudden frost when everything was still green. A lot of plants held onto their leaves. The result was that no matter how many times I raked this winter, more leaves kept falling!

In any case, even if there is dieback, Crape Myrtle is capable of coming back from the ground.

Crepe Myrtles are the last plantings to "come back to life" in the spring ... and one of the last to go dormant in the fall. Do not cut it down unless it's still "dead" in July.

If the wood is still green when you scratch off some bark, it's still alive. We have a Natchez in NE PA that we were convinced was dead - no budding through the middle of June. The bark was still green. I was told by an internet Crepe expert to throw in the towel. I actually bought another one and planted it, leaving the original out with exposed roots. Came back from a weekend at the NJ Shore, and buds had sprouted. I replanted, and it did great.