I love the sansanqua camellias. They've come a long way since the earlier cultivars and I've really enjoyed the ones I have. I have both a beautiful pink (I love pink flowers) and white, my all time favorite bloom color. And they bloom when there's nothing else in bloom.

Gardenias - they will smell fantastic. If you get the August Beauty variety, they will bloom off and on all summer. They would be everggreen in your zone.

How about Mexican Heather, Annie? I think they make a great low border.

Box does great in Houston, in FULL sun. And it is hot as heck here too (it also rains a lot...) I know that when I see a new hedge planted it always seems that one goes belly up in the first year. But if you replace the duds (but get the rest established) you should have a beautiful hedge in a few years. The ones in front of my house are at least 30 years old. Unfortunately I don't know the exact type...will try to find out.

Sasanqua camelias will grow far taller than 30-40" tall, but they are lovely. If you try to keep it pruned to look neat through the summer you will remove most of the flower buds. If you decide on a taller hedge and go that route I can highly reccommend a variety called 'Jean May', it is a double pink (flowers look very much like a rose) and starts blooming around mid Oct.
Gardenias will also grow much larger than 40" and attract white flies like crazy.
Arp Rosemary will also grow quite tall but can be pruned effectively, as witnessed by the little ones they shape like Christmas trees seen in all the big box stores.
As for the others, I haven't grown them, so I can't help there.

Serrisa would be a good choice. Everyone thinks of it as a bonsai plant, but it thrives in this climate in bright sun. The tiny leaf structure sounds right for what you are describing and it takes heavy pruning/shaping very well. Easy to keep narrow and upright. Blooms several times a year.

August Beauty Gardenias get more like 6'. You might try some of the smaller varieties of gardenias.

Indian Hawthorne might be a good choice for a low evergreen hedge that doesn't need to be sheared too much.

I love Camellias but most of them are going to get much higher than 40".

Some of the small leaved Azalea varieties might be a good choice. Of course, that would be only if you have acid soil. I don't remember if Houston has East Texas acid soil or Central/West Texas Alkaline soil....

Arp Rosemary might be a good low screen for that area as a previous poster mentioned.

The best plant is going to depend on how much sun you get and how wet/dry the area is.

Thanks for all the guidance. I'll check them all out but am leaning towards rosemary right now as I know it thrives in the location and grows pretty quickly here too. Then again, if I can find a good boxwood I may have to give that a try.

I'll have to look up the camellia "Jean May' for another use in my yard as it sounds right up my alley.

Thanks again.

I like Rosemary and of course ~Serrisa~ as above post suggested. Another very good one that takes well to heavy pruning is
Myrtle communis 'Compacta'. It has fragrant leaves, flowers and fruit. I am not sure if it would thrive
in your climate zone.

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