Some catalogs list North Pole as trademarked but don't say anything about patent, while they do list other varieties as patented. Does that mean you can propagate but not use the name?

Yes trademark means that, but it still could be patented.
A guy here does patent searches a lot, maybe he will chime in?

You can do a Plant Patent Search on Google Patents, but I only get "hits" 50% of the time.

That's not true. It is true you cannot call it pink lady, but you could call it anything your heart desires. Pink Mrs. would be fine! Many places do this, and it makes it extremely confusing. Gardens Alive trademarked the name Sweet Repeat. So far a black raspberry and a red are described this way depending on what affilate they use to sell. At Henry Fields Sweet Repeat is the Niwot black raspberry. At Gurneys it's Nantahala. Henry Fields only sold Niwot last year, it it not selling it anymore. Nourse sells it now under Niwot. I bought mine from Henry Fields as Sweet Repeat. Gurneys is still selling Nantahala as Sweet Repeat.

Using the search terms "apple AND tree AND named AND columnar AND malus" I get some columnar apple trees, but not some that I'm pretty sure have patents. Or maybe they are PPAF instead.

The variety "Maypole" was filed in 1986, so I know it's possible that some columnar apple trees are off patent. Somewhere in their lineage, I think they all trace back to MacIntosh mutant Wijcik variety (U.S. Plant Pat. No. 4,382)

Weatherman, thanks I haven't tried those terms yet. Will try.
Bradybb thanks, I hope that means North Pole is off patent.

So complicated!

For example, the pluerry, a plum-cherry-peach-apricot hybrid, is trademarked as "Sweet Treat" Pluerry but it is patented as ""Sweet pixie 2" (patent 23796).

PP##### All plant patents are preceded by PP and are followed by 5 digits. Where shown with 4 digits you need to add a zero after the PP when searching by patent number.

http://patft.uspto.gov/

http://www.freepatentsonline.com/

Sellers are supposed to post the patent number if active with the description since they are charging you a royalty fee to honor the patent. I have seen some sellers omit this info

Plant patents are good for 20 years from the filing date. You cannot legally graft or propagate a patent protected plant until the patent expires without a royalty agreement. This is why expired cultivars may take about 4 years post patent before you start to see them widely available. I haven't looked in a year but around PP09000 is the 20 yr expiration point.

I doubt Northpole or any columnar tree is patented (though Scarlet Sentinel was applied for). I believe they are not genetic but represent a style of graft/cut that produces the form (spurs along "trunk")---but I could be wrong. If I am right it can be grafted but will not graft the way you think in the manner of producing columnar fruit trees without training. But I have yet to discover their secret. Love to find out I am wrong about this???? You do need to prune them differently; keeping up removing any outgrowing branches and not topping it.

The only reason I want to use it is I have one in my yard already and would like another. I like to play with grafting and they are too expensive to buy another one just for novelty.

They really arent that great an apple, but they make a handsome specimen tree as they age, especially with judicious pruning of the longer spurs.

Wijcik was discovered in 1961 by an orchardist of that name. The patent was filed in 1978 by Starks.

The original Wijcik was around so long before being patented, there might have been opportunity for development of multiple new strains before the original was marketed, and even after that. None of them seem to show up on a Best Flavor list. They are just a novelty.

One progeny was Golden Sentinel. That was being trialed in 1996 in Canada - where Wijcik originated- but I think NorthPole is older. I am pretty sure my North Pole tree is at least 15 years old, and I doubt it was one of the early ones.

I would be curious to see what happens with crossing these with an ornamental, disease resistant crab, like Prairie Fire. Select the columnar, red leaved seedlings... Probably small sour fruit with red flesh. But it would look cool.

I am not surprised they are not taste winners...first gen oddballs rarely are. I have 2 each of Golden Sentinel, Scarlett Sentinel and Northpole all on M7 which seems to do well here as far as growth. I bought them with the idea of shading the western side of a tool shed I have. I decided after they were here they would be too close to a trellised grapevine and so planted them on the eastern side of the shed. Year 3 and they are about 8 feet tall now. Not sure if there will ever be enough chill hours to fruit. Would have gotten a bit more on the west side. They flower but I pinch off the flowers after the bees are done. The Golden Sentinel produced a surprise 3 apple cluster at the top (that I missed) this year. They were OK. Next year I will let them all fruit if they will.

From what I have found, many descendants with the McIntosh Wijcik Co mutation have been patented or will be. That I think goes with the territory for a mutation that occurred just 50 years ago. Any apple being developed in a modern research program is going to be patented and controlled. That goes for new columnar crosses and especially true since columnar trees could reduce growing costs in a high density orchard. There is high commercial potential for a great columnar apple. Unfortunately, a blockbuster variety would be a tightly controlled, commercial release that would not be available for us to plant.

There were several patented by Kenneth R. Tobutt from the 1980s or early 1990s. I found literature on columnar apples from eastern europe and japan. A number of recent patents are from the Czech Republic (Institute of Experimental Botany AS CR v.v.i,). I found a paper from Latvia that examined 26 columnar varieties on 6 different rootstocks (http://sodininkyste-darzininkyste.lsdi.lt/straipsniai/25-3/25(3)-7.pdf).

Given the amount of time it takes to develop new varieties, it will be a while until there are many great columnar apples. Most are still too close to the McIntosh. Normal apple trees have a head start of several hundred years.