Japanese holly will grow somewhat faster than boxwood does but I'd not describe any cultivar as "fast growing"! To avoid much of a need for pruning, I'd go with one of the more mounded, compact cultivars like 'Compacta', 'Green Luster', 'Hoogendorn' or 'Hetzii'.

Helleri is a great shrub but gets larger than one might imagine, especially with its spread.

@gardengal48 (PNW Z8/9) Thanks for the info! Curious as to your thoughts on something like "Schwoebel Upright" for that space? I really need to keep it no more than 3ft wide to fit the space, but want 4-5ft tall (and have room to go taller if deisred later).

My helleri shrubs are dwarfed, they have not gotten larger than 3 feet, and I have had them for several years. I researched this dwarf shrub as I wanted 3 shrubs that would remain 3 feet in width!!

Helleri can spread to 5 feet or more. I have seen some massive specimens, which have probably never seen pruners, but I assure you it will not stay limited to a 3' spread without pruning!

@chigal1, I am not familiar with that cultivar but what information I did find indicates it will also exceed a 3' width.....but not by too much. It also seems to be a bit fussier about growing conditions than other J. holly cultivars but I can't confirm that.

Thanks for the feedback!

Deer will be a problem. Would one of the small junipers, like 'Tortuga' work?

@laceyvail 6A, WV Not opposed to a Juniper, but Tortuga is shorter than what I would like. I want to hide the trellis.

Most sources list Japanese holly is being deer resistant. They have about as much appeal to deer as boxwoods do.

Check out Ilex glabra GemBox or StrongBox.

There are several other narrow clones of Ilex crenata. Take a look at 'Sky Pencil' and 'Jersey Pinnacle'. They are probably not much different than ' Schwoebel Upright' - with which I am not familiar.