"newly planted" might be the key phrase here. Established plants - 1 or 2 full seasons - have a more established root system and will usually come back. I would wait and see if you get some new growth near the base of the plant before you give up. But this was unusually cold for here, and that will happen from time to time. Covering helps. Lantanas and pentas are not really considered "tender" plants here. After a few times losing plants, you will be more selective in future - I know I am, but still, if there's something I love, I will plant and cover when indicated.

Leave them for now and then trim back the dead parts med March. You’d be amazed at what grows back

My coreopsis (also known as tickweed) that were only planted a month ago suffered no damage and will bloom again in the late spring thru the summer.

Thanks .. the only part I disagree with is but this was unusually cold for here because we have been here 5 years and every year has had at least 1 "deep freeze" including the first week we moved in here in early January 2017. I was ready to demand a refund! :D

Cut an inch from ground after last frost and they will grow back!

Time To Get Rid of These plants?
 

Avoid the temptation to cut off dead growth on plants until about mid March when last frost warnings are over for our area. The dead growth actually protects the live parts of the plant from future frosts yet to come. Many pentas will actually com back after removing dead growth in mid March. Vinca is a colorful flower that will almost always come back after frosts, lantana comes back and hibiscus. Knockout roses will bloom all year even through frost and roses can be pruned mid Feb.

Agree...
:):)

WAIT! Don't cut them til March!
 

I am learning about our plants in this area (we are mostly all from elsewhere!) and asked a local landscaper if I should cut back the "dead" parts of my plants. The answer was "NO!". Wait til end of April or into March--whatever you cut now will be vulnerable to the next frost and it will probably kill it. What we think right now is "dead" may in fact not be totally gone!
:a040:

Not as cold as 3 years go when it got down to 26 in my area three nights in row. All my tropicals survived and came back bigger. But I covered them up and the was well establish and woodie. Young plants don’t have much of chance when it gets below freezing for several hours or days IMO.

Snap dragons also good.

Truly simple advice from an old neighbor from a different era and a different climate zone.
It isn't dead until it is dead. It may well come back in the spring. There is NO REASON to dig it out now. Dead material, you can always remove it later. Procrastination and sage advice often can be the same. Both save a lot of useless WORK..
SPRING FEVER can be dangerous for your plants.

Marginally hearty plants. You can IF you choose to baby them, PERHAPS, force them to survive. Will YOU always want to. remember to, be able to, baby them. ARE THEY WORTH THE TROUBLE????????

Beware of trips to the garden centers and big box stores. Even MONSTER plants look pretty grown under IDEAL conditions. READ before you buy. Plants from neighbors?
Also beware. Why do they have plants to give away? Often it is because they are taking over their yard.