ChrisK, This is from a nursery's description of the NSH, they sound perfect for your requirements. Ideal selection for hedges and privacy screens Grows up to 3 ft. per year! Thrives on neglect YouÂll appreciate how these holly trees stay deep green all year, unlike other hedge trees that can brown out during either the summer heat or mild droughts. Plant 5-6 ft. apart for a living wall that gives you complete privacy -- no holes or gaps. You control how they grow  whether naturally into a dense, pyramidal shape that matures at 15-25 ft., or pruned into a tall box hedge. They grow up to 3 ft. per year without pruning. When they reach the height you want, just clip off the leader. This will slow them down and make them thicken. These holly trees make perfect accents at the corners of your home, in the flower garden or entryway. The dark green foliage makes a great contrast to surrounding trees and shrubs. During the winter months you will enjoy the red berries against the deep green foliage. Clip some branches to decorate your home for the holidays. Bird watchers delight as these berries attract all kinds of wildlife!

What roses are they? I ask because I have seen this combo looking rather good but it was very large shrub roses (Alba semi-plena) planted with equally large English holly( Ilex aquilfolium, possibly Silver Queen) and very deep green Japanese holly, Ilex crenata.....as part of a huge boundary hedge.....it was an extraordinary sight at all times in the year but had nothing of the formality of some rose/evergreen combinations. Planting wise, they enjoy similar conditions so I see no problems regarding maintenance requirements (apart from the prickly ones). As a rule though, unless your roses are the same colour, adding variagation to the mix can be a bit eye-achy.....so a plain holly might be more serene and harmonious in a mixed rose bed.....but obvs, ymmv.

I have one Nellie Steven. About 18 months ago, I had one large Maple tree removed from the front (due to disease and crowding), well, I noticed that the Nellie Stevens was completely lopsided as half of it was in shade of the Maple. The part in the sun, was growing fast. I have other Hollies (Japanese, Blues, China series...so, I noticed the difference. Now, I expect it will recover some decent shape as it is in full sun. So, this variety can handle full, southern exposure and a good deal of heat. Meantime, my Blue Princess/Prince holly that are in shade are fast, those in the sun have either never taken off or seem stunted. Location, location, location as they say! I suspect the clay soil is less of a factor, my soil is also fairly clay. Makes a great tree if provided its space. Birds also love the berries (had a flock of wild turkeys crazy about them a couple of weekends ago).

Nellie Stevens is a hybrid between English and Chinese holly, so if you get a male Chinese holly you will be assured of heavy fruiting. Dirr lists two male cultivars, Gable #76, which is short and pyramidal, and Tall Stallion. I've heard that Chinese hollies don't need males too, but then why are there so many Nellie Stevens around that don't fruit much? Too young, pruned at the wrong time? I've always wondered. There is a gorgeous Nellie Stevens at the front of Pender Nursery in Garner that fruits heavily, but there's hollies all over the place there, as it is a big wholesale nursery. One of the guys told me that the one there was 15 years old at the time and it takes a while for Nellies to look like that one.