They will be fine with the single digit temps. Cold as he// for us but they will show no damage. Used to have a nice specimen of a much more prickly culitvar. Don't worry, they will survive.

Sam, these particular hollies bear observation after severe cold. Their hardiness depends on lots of factors. Wind exposure, root system establishment, pruning and fertilizing timing, and even irrigation practices will all affect this plant's ability to go through a tough winter.

We had a freak storm several years ago and my 10 foot cornutas (with three foot of snow pack...odd too), frozen back to 1-2 foot stubs (if not to the ground).
We recorded -27F at my house in NE Oklahoma...where normal extreme lows over the past ten years had been 5-10F each year.

Could be 'Needlepoint'. Dwarf Burford has leaves with more texture and seem to be more recurved along margins. Of course Needlepoint is a more upright grower.

You'd have to compare to regular Burford and maybe also with I. cornuta 'Fine Line'.

I have been finding the wild offspring of these shrubs in my woods over the past few years. Believe me those "horns" HURT if you bump into them. Thankfully they're slow growing so easy to keep controlled.