Your idea about a sasanqua might be good were you to resign yourself to pruning it as a small tree. Those not of the weeping variety can get quite large, the weepers tend to get wider than would be useful on a sidewalk verge.

We planted some next to the road and they are subject to every blast of inclement weather; there is no cover whatsoever. They develop a bronzed look in winter but do not scald. On the whole, they are very pretty and I would recommend them to anyone...in fact, I have hundreds of volunteers should anyone want some.

Daisy gardenia seems quite winterhardy and develops a squat, rounded shape about four feet tall.

I've seen some Carissa hollies that are 6' but it takes awhile to get there. Grey Owl junipers might get that tall, one of my favorite shrubs.
I'm not sure what you mean by sticky... but you want dense?
Dense deciduous only? Or dense evergreen?
If that is the case, I have a hedge of knockouts approaching 7' and I do little to them and they are not super dense but are magnificent.

Thank-you.
What I need is impenetrable physically and visually. Here the City we can only have front fences that are 4' tall and have 50% visibility.
This does not address the rapid increase in violent property crimes effecting many neighborhoods.
Not that I have been a victim, but I am looking to lessen the opportunity of becoming a victim. We can plant what we like inside our fences at this time...I'm really looking for unfriendly evergreen species.

I would look into knockouts because they have some whopper thorns, as I'm sure you know already. But while I have seen some very round knockouts, mine have formed a rather narrow hedge under 3.5'deep with minimal pruning and absolutely no watering other than rain. They are approaching 7' in height.
I can still see through the hedge but could not penetrate with my arm. They get full sun all day.

I have originals, pink, and blush in other areas of the yard and the originals are the only ones that are blackspot free and vigorous. I lost a blush this year probably to drought.
The hedge which is about 70" long has some original knockouts that are own rooted and some grated. The grafted ones have bigger canes and have grown faster. I've had the hedge for about 5 years and bought every ko in the fall at half price.
Just a thought.

I have knock outs. They are not large or dense enough, unfortunately. I don't want anyone to see what is behind them at all!!
The camellias would work as a visual deterrent. I would grow them right to the ground, if I'd have enough room, I would plant roses in front of them (I've already got many roses in this spot, you can just see through them too much!!).

Can camellias handle full sun all day here? I've always thought of them as a morning-sun plant. They'd make a beautiful screen if they can take the sun.

If you want flowers, another option might be a Callistemon Woodlander's Red. I've seen a hedge of this in a coastal town in SC and it was beautiful and dense. I ordered one from Lazy S's which is small but happy so far. The height is listed as up to 5', but Lazy S's description says the arching branches reach up to 10'.

Abelias are also quite dense (with scratchy branches) and flower well in full sun. Canyon Creek reaches 5-6' i think.

Eleaganus (really big thorns!), privet, loropetalum would all be good options for a dense hedge, which could be sheared (the first two just to reduce their invasiveness), if you are considering a traditional hedge.
(A garden I drive by has a sheared box-shaped loropetalum hedge at the street with a super cottage garden behind and purple trim on the house -- looks great!)

Here is a link that might be useful: callistemon

I have had about 30 different camellias at various times -I've lost some to drought- and Kanjiro and Chansonette are the most vigorous far beyond the others. They are in full sun.

camellias are so slow to grow that they could be useful to you as a barrier that would not require much immediate maintenance for height and width restrictions yet provide evergreen visual screening. if you like hot pink, 'shishi gashira' would be a good subject. my old shrub is much wider than tall and has reached almost 6' high after 20-something years (no pruning). the individual flowers are not that beautiful in form to me but the floral display of the shrub in full bloom is eye-catching.
'chansonette' has very pretty flowers, is about the same color, grows low and spreads laterally in an almost weeping fashion.
'shishi gashira' in autumn:{{gwi:833735}} 'chansonette':{{gwi:833737}}

Edible Eleaganus are definately a choice for the hedge. If it were something edible it would be icing on the cake, but I'll take pretty. Jeff, you make a very good point about the camellias and time it takes to grow to size.
Abelias are a strong possibility. They grow so fast, and I love their honey scent. I had one in the back which was moved, but because the city took so long to get the permits going it died. I think it was just the species of glossy abelia and grew about 8' tall.

I have never really had a lot of shrubs - or at least full grown shrubs. Actually we have quite a few shrubs but most of them were started from cuttings, so it's taken them a VERY VERY long time to get going.

Thanks for your help. Everything is a consideration (except for privet. My fear is overusing lorapetalum. I love it a lot, and have used a lot of it so far :) I'm a sucker for anything with purple leaves!!

My chansonette has been in the ground for 4 years and it is approaching 4.5'. I think that is fast growth from a gallon pot from Lowes. I have whacked it back considerably each year for the past 3 years just to bush it out.
I regret, lol, almost every shrub I have planted for fast growth as they grew bigger than I ever expected and I am always pruning or with perennials, dividing and moving around.

GGG - I think I have mentioned this before, but how about mahonia? It is seriously deadly when it comes to sharp leaf tips. I planted some along a wall so that our kids won't be tempted to use the wall as a jumping off entertainment place. It works! I have been stuck so good that I bled and bled. Hurts! If someone tried to go through a closely planted bunch of mahonia, they would regret it. You could plant them in two rows, alternating placement, so they would form a dense barrier.
The flowers smell lovely in late winter, and the berries are - I think - edible! Many species of birds love the berries too, so that is fun, if you like to watch birds.
I got a bunch of mahonia from a friend - dug up some pretty mature ones, and they all survived.
I also think they have a very interesting sculptural quality, depending on how you let them grow -- whether you do or don't choose to prune them.
From what I can tell, they grow very well down here -- so that might be a good choice.
Good luck!

GGG- tea olives can handle full sun- I have three that do, and I love them. But they will grow to be 20-25' tall. I've never seen them shrubbed, but I suppose you could do it. If you're not dead set on evergreens, you might consider fothergilla and/or itea. Both have beautiful fall color. I also like Mahonia and have several- you will to, because the birds will spread their seeds and you will get plenty of volunteers.
jg

For those that don't know, the Mahonia that you see "volunteering" is Mahonia bealei - a non-native plant that is currently a Category 3 invasive plant on the Georgia list. It is related to barberry.

While not the worst invasive, it's not something that I would recommend using to anyone.

I'm with you, Esh, I currently have three of them planted around a set of windows but would like to replace them someday. Just have not found the right unfriendly sized plant that could take their place yet in my garden of unfriendliness filled with prickly pear and yucca so far!!

There's a reason that "thorn" is part of the name "Hawthorn". I naturally have Crataegus uniflora - a smaller, dense, deciduous shrub:

{{gwi:332363}}

Esh, can it take clay?
I had one native hawthorne. It lived for 3 years. Two years in a row it got borers. Two years in a row it seemed to get what looked like fire blight. Year three it was removed.

I'm wondering if this can stand clay? I can't mind much about it, but what I've found says it would prefer sand.

Mayland: yes, you can grow camellias in the sun, however japonicas will be subject to sunburn/winterburn if they do not have sufficient moisture and shade for their roots to keep them cool. Their blooms (particularly the white or red formal doubles or peony forms) will also be subject to ruin by the rain or sun in open situations.

Camellia sasanqua does much better in such exposures as it is both more sun and drought tolerant. Their flowers are generally not as badly harmed by open situations insofar as most have simpler flowers. They also grow much faster than the japonicas as a general rule.

I would highly recommend sasanquas for full day sun (given sufficient moisture), but for small areas like sidewalk verges weepers will have to be hacked, thus losing most blooms and its' natural shape, or more vertical types pruned as small trees.