How about barberry. I have them in shade.

http://www.bhg.com/gardening/plant-dictionary/shrub/barberry/

That is a possibility. I don't think the thorns stick out from the leaves, however, so couldn't one brush past one?

Barberries are quite uncomfortable, as someone who grew up with a hedge of them. Whatever you plant, plan on putting up metal fence posts with a wire fence for a couple of years, otherwise your visitors may end up breaking branches and damaging the plants beyond repair. It usually takes a bit to change behavior.

mahonia...and the ubiquitous but cheerful pyracantha

I admit to being fond of berberis but now never mention it because it invariably causes shudders of horror - nooooo invasive. Along with spindle (euonymous alata) and Callery pear, this demonic trio seems to get all Americans united in loathing.

Chris G is in the Pacific NW where barberry doesn't seem to be an issue as far as invasiveness. There are some nice gold or red varieties that would combine the function he wants with ornament. Their only drawback for this type of function is that you may need to periodically rake out blown leaves and trash since the thorns do sometimes grab things.

Not me!! I love barberries, grow a number of different varieties and their invasiveness is restricted both by species and location. Obviously, invasiveness is not a concern in my area (PNW also). But they are not a happy plant in the shade. btw, the holly one sees here is usually English holly, Ilex aquifolium and it IS invasive (thanks to the birds) which is why it appears to grow 'naturally' in this area :-)

The obvious choice to me is mahonia and one of the taller growing, winter flowering cultivars of Mahonia x media, like 'Charity' or 'Winter Sun'. shade tolerant, evergreen, large prickly leaves and sweetly smelling winter flowers that attract hummingbirds. Besides the pyracantha, I'd also consider ghost bramble, Rubus thibetanus, but both only happy in at best partial shade.

Having once had the pleasure of seeing and smelling an early spring Mahonia in a remote Utah canyon, I would just love being able to grow one.

Gardengal, I actually have 3 Charity Mahonias in front of the well house, in full
afternoon sun. I think they need more light than the area would
provide. They are interesting to look at.

NHBabs, I looked for red and gold varieties and came up with the Sunjoy Gold Pillar and Golden Ruby Barberries. The former grow up narrow and the latter is said to make a round shape. Two Gold pillars behind a Golden Ruby would fill the space nicely.

Um, terribly sorry to lower the tone here but 2 round balls and a tall (red!) pillar shape is bringing something distinctly...phallic...to mind (obviously, having been brought up in the sewer).

Chris G., if I can grow them in shade they should be fine in some shade because you are warmer than my area. I have a really pyramid one that is orange in the spring and yellow late summer. A really pretty one that is red and it blooms small yellow flowers in late Spring. I like them I do not remember the names I picked them up at my local nursery and they are at least a plant the deer do not eat. I have so much trouble trying to garden with all the critters.

There may be some shade-tolerant roses you could use. Examples include Ballerina or Trumpeter.

Speaking of critters, your treaspassers could be deer.

Camps it's the other way round: 2 pillars and one round. I read it as you did and then went back to reread . . . I've seen some photos of unfortunate plant choices. ;>)

Deb, I think I'm going with the Barberry.

Cozycabin, I have surveillance camera images.

NHBabs, I have the image in my head of 1950's beauties in those futuristic (for men at least) long conical bras. However,I will not comment on the mound.

color can be significantly effected by lack of direct sun ... if you are looking at any of the colorful barberries ... but as with any shade issue ... you just have to try it.. and see what happens ...

e.g. a yellow plant in full shade MAY tend toward green ...

ken

Thanks for the warning, ken

"e.g. a yellow plant in full shade MAY tend toward green ..."

And the reds and oranges will be much more green in color as well. Japanese barberries are really full sun plants. But if you don't mind the lack of color intensity, it should work well for your purposes.

I've seen reports of a few studies that found higher populations of deer ticks in areas with Japanese barberry. Good to keep in mind.