i see several norway spruce around here. in fact, i have one that was a b&b christmas tree in the mid-90's and it is looking good (about 12'-15'tall now). they probably grow larger than your desired height of 20', though.
here is a photo of a cryptomeria japonica (labeled 'black dragon' by mistake, i believe) in louisiana that is quite old. i have the 'black dragon' cultivar of this species but it is still in its container. i have heard they grow to about 20' and c. japonica do well in the south.
you might do a search for "dwarf conifers" for listings that fit your height. some will be true dwarfs or miniatures but others will be slow growers to about that height or smaller.
hopefully, someone with more experience growing these will offer suggestions.
i love the looks of conifers in the winter landscape, esp. the ones that grow well in northern climates. most of the those that i want to grow are not suited to our climate. :-(

Here is a link that might be useful: cryptomeria photo

May I comment on your reason for using an artificial tree? Xmas trees come from established farms, where they are grown just like any other agricultural crop. They are planted, sprayed, fertilized, shaped, inspected, and then harvested for public consumption. The use of these trees for our enjoyment is no different than puchasing a dozen ears of corn, or even a loaf of bread!

Tree farms are often owned and operated by families who's livlihood depends upon good agricultural practices. Perhaps you are missing the final step: after trees have been harvested, they are replanted again for the next cycle. No tree farmers cuts all of his trees each year, but a relatively small percentage, all of which will replaced in short order.

Truly, the only wasted Xmas tree is one that was not selected to adorn someone's living room.

Now! I wish I could come up with a conifer that would happily stay under 20 feet. But you could think in terms of a broad leaf evergreen that would look wonderful all decked out in holiday lights! In the South, magnolias fill this bill readily, as do some of the tree hollies.

Hi, Susan. You might want to make a list of local good nurseries and call them to get their suggestions. Then look at the trees more than one suggests to pick what you want. I totally agree the needles are a pain.
I'll probably hear about this from someone BUT what you want to do is your business. Oh, by the way, don't eat the tree, it is NOT like buying bread or corn. Heh heh I just couldn't let that one pass me by.
Hope you all are doing well and find the tree you want.
Lynn

Actually, you COULD have let it pass you by. Too bad! lol

I totally agree that there's not much you can do about the needle issue! Unfortunately, unless one visits a 'cut your own' business, farmed trees are harvested sooooo early, and there's no telling how they are stored until shipment to the seller. And we've all seen how the typical seller displays them. It's a wonder that they have any needles left on them at all! Those who live in colder climates are luckier in regards to this, though. As long as the trees are stored outside, they'll do better than those basking in the warmth.

Say, Susan. One holly, in particular keeps coming to my mind for your purpose. The Foster Holly, a lovely pyramidal tree holly, sets a nice crop of berries without the need of a nearby male pollinator. Half the decorating would be done for you! You can purchase them with branches all of the way to the ground or limb them up to display a single trunk, if you like. Though a healthy, vigorous specimen could get over the 20 feet you specify, it would do so over a long period of time, and they grow slowly once mature.

If you can't find a conifer that suits you, you might want to take a look at this holly.

Here is a link that might be useful: {{gwi:369748}}

Thanks for all your suggestions. I like the holly but will look around. I'll let you know what I finally get. Susan.